IMMUNOLOGY

UNIT-1

2 MARKS:-

1) What is immunology?

It deals with the study of processes by which the body defends itself from the invasion

and attack of foreign organisms.

2) What is mean by Attenuation?

The process of weakening or reducing the virulence of pathogenic organisms without

losing the capacity to induce immunity.

3) Define immunity?

Immunity is defined as the resistance to infection. This is carried out by the process of

recognition and disposal of non-self or foreign material that enters the body.

4) What is mean by adoptive immunity?

This is a type of passive immunity produced by injecting immunologically competent

lymphocytes and not by injecting antibodies. This method is adopted in the treatment of

tuberculosis and leprosy.

5) Define Rh factor?

Landsteiner and wiener (1940) discovered the existence of a special type of antigen in

the RBC of Rhesus monkey. Since this factor was first discovered in Rhesus monkey, it

was named Rhesus factor or Rh factor.

5 MARKS:-

1) Differentiate between innate and adaptive immunity?

Innate Immunity:

All living organisms are naturally gifted with the resistance to certain infections

from birth and this natural defense mechanism is known as innate immunity or

native immunity or natural immunity.

Adaptive Immunity:

The resistance developed by man during his life is known as acquired immunity

or adaptive immunity.

2) Write about phagocytosis role in immunity?

Phagocytosis is a process of “cell eating”.

The phagocytosis cells discovered by Metchnikoff (1838) are two types, namely

microphages and macrophages.

These are the professional phagocytes but on occasions, other cells also perform

the function of phagocytosis.

Process of phagocytosis:

The process of phagocytosis includes the following stages: Chemotaxis,

Attachment, Ingestion, Intracellular, Killing and Digestion.

3) Write about passive immunity?

The immunity that non-immune individual acquires by receiving antibodies or

sensitized white blood cells from another immune individual is known as passive

immunity.

a) Natural passive immunity:

The immunity transferred from the mother to the child passively is known as

natural passive immunity.

b) Artificial passive immunity:

Transfer of immunity from an immunized donor to a non immune recipient by

transferring antibodies or immunized lymphocytes is known as artificial passive

immunity.

4) Differentiate between active acquired immunity from passive acquired

immunity?

Active acquired immunity:

Active immunity is the resistance developed by an individual in response to an

antigenic stimulus. Active immunity involves the synthesis of specific antibodies

(humoral immunity) or production of immunologically active cells (cell mediated

immunity).

a) Natural active immunity:

Immunity is developed by the host in response to antigen that enters by natural

infections.

b) Artificial active immunity:

Immunity is attained by the host in response to the antigen got by vaccination.

Passive immunity:

The immunity that non-immune individual acquires by receiving antibodies or

sensitized white blood cells from another immune individual is known as passive

immunity.

a) Natural passive immunity:

The immunity transferred from the mother to the child passively is known as

natural passive immunity.

b) Artificial passive immunity:

Transfer of immunity from an immunized donor to a non immune recipient by

transferring antibodies or immunized lymphocytes is known as artificial passive

immunity.

5) Describe an account on Rh blood grouping?

Landsteiner and wiener (1940) discovered the existence of a special type of

antigen in the RBC of Rhesus monkey. Since this factor was first discovered in

Rhesus monkey, it was named Rhesus factor or Rh factor.

The Rh factor is also present in the RBC of some human beings and it is absent

from others.

Based on the presence or absence of Rh factor, the human beings are classified

into two groups.

They are Rh positive (Rh+) and Rh negative (Rh-). The Rh+ person has Rh antigen

on the RBC; the Rh- person has no Rh antigen.

Genetics of Rh factor:

There are several varieties of Rh antigen and of antibody. The commonest Rh

antigen is called antigen D and its antibody is called anti-D.

There are two views regarding the inheritance of Rh blood group. They are as follows.

1) Weiner’s theory.

2) Fisher’s theory.

Prevention of hemolytic disease.

Treatment.

10 MARKS:-

1) Give a brief account of the history of immunology?

Though this branch is quite young, history shows its origin even about 2,500

years back. The following are the classical and outstanding works of a few

eminent scientists and their contributions to the field of immunology, starting

from the Greek Thucydides of the time before Christ, up to the late 20th century

immunologists.

1. Thucydides (430 B.C)- pointed out the people who were once attack by the plague

could not get the fear of the second attack of the disease.

2. Variolation (12th century) - inoculation, small pox was known as variola.

3. Edward Jenner (1749-1823)-developed a scientific and far safer method to small pox

immunization.

4. Louis Pasteur (1822-1895) - father of immunology, produced vaccine for rabies.

5. Robert Koch (1843-1910) – identified the causative agent of tuberculosis.

2) Write an essay on the various phenomena of innate immunity?

All living organisms are naturally gifted with the resistance to certain infections

from birth and this natural defense mechanism is known as innate immunity or

native immunity or natural immunity.

The mechanism is effective against a wide range of infectious agents and it

operates through many factors such as,

a) Physical and mechanical factors.

b) Biochemical factors.

c) Cellular factors.

d) Genetic factors.

e) Other factors.

3) What is blood transfusion? Describe the immunological aspects of blood

transfusion.

The transfer of blood from one person to another is called blood transfusion.

The person receiving blood is called recipient.

The person donating blood is called donor.

In blood transfusion the ABO grouping should be tested.

Distribution of ABO blood group.

H antigen

Bombay blood group

Secretors and non-secretors.

4) Give an account of the vaccines used in the prevention of various human

diseases?

Vaccine is an antigenic preparation of microorganisms such as bacteria, viruses

or rickettsiae, administered for prevention treatment of infectious diseases.

The vaccines are classified into the following types:

1) Homologous vaccines.

2) Heterologous vaccines.

3) Cellular vaccines.

4) Sub-cellular vaccines.

5) Attenuated vaccines.

6) Inactivated vaccines.

7) Toxoid vaccines.

8) Sub-unit vaccines.

9) Recombinant vaccines.

10) Mixed or combined vaccines.

11) Autogenous vaccines.

12) Freeze dried vaccines.

13) Antiviral vaccines.

14) Antibacterial vaccines.

15) Anti-rickettsial vaccines.

5) Describe the ABO blood grouping?

The typing of blood, for ABO group, involves agglutination reaction.

For typing blood, a drop of the blood sample is mixed with a drop of

antiserum A and another drop of the blood sample is mixed with a drop of

antiserum B on a glass slide.

If the blood sample is clumped with antiserum A, the sample belongs to

group A; if the sample is clumped with antiserum B, the sample belongs to B,

if the sample is clumped with both antiserum A and antiserum B, the blood

sample belongs to group AB. If there is no agglutination, the blood sample

belongs to group O.

IMMUNOLOGY

UNIT-2

2 MARKS:-

1) Comment on lymphoid organ?

The organs concerned with immune reaction are called lymphoid organs. They contain

lymphoid cells (lymphocytes).

The lymphoid organs and the lymphoid cells constitute the lymphoid system.

The lymphoid organs are two types:-

a) The primary lymphoid organs (central).

b) The secondary lymphoid organs (peripheral).

2) What are the primary lymphoid organs?

1) The thymus.

2) The bursa of fabricuis in birds.

3) Bone maarow in mammals are the primary lymphoid organs.

3) What are the secondary lymphoid organs?

The secondary lymphoid organs include:

1) Lymph nodes.

2) Spleen.

3) MALT.

a) Peyer’s patches.

b) Tonsils.

4) Describe MALT?

MALT is the Mucosa Associated Lymphoid Tissue.

The mucosal layer of the alimentary canal, respiratory and urinogenital tracts is

provided with dispersed groups of lymphoid tissues known as MALT.

5) Define lymphocytes? What are the three types?

Lymphocytes are mononucleate, non granular leukocytes of lymphoid tissue,

participating in immunity.

They are lymphocytes are of three types. They are

1) B lymphocytes.

2) T lymphocytes.

3) Null cells.

6) Antigen presenting cells?

The cells which process and transfer the antigen to lymphocytes are called antigen

presenting cells.

7) What is haemopoiesis?

The stem cells develop into blood cells through a process called haemopoiesis.

As the stem cells develop into blood celss, they are also called haemocytoblasts or

haemopoietic sten cells.

5 MARKS:-

1) Explain bone marrow as a primary lymphoid organ?

Bone marrow is a primary lymphoid organ.

It is soft tissue within the cavities of bones.

Marrow is divisible into two regions, namely

a) Vascular and adipose region.

b) Haemopoietic region.

The stem cells develop into blood cells through a process called haemopoiesis.

As the stem cells develop into blood celss, they are also called haemocytoblasts

or haemopoietic sten cells.

Fuction of bone marrow.

2) Explain the immunological functions of spleen?

Spleen is a secondary lymphoid organ.

It is a solid, encapsulated organ located in the upper part of the abdominal cavity

behind the stomach and close to the diaphragm

Function of spleen:

1) The graveyard for worn out blood cells.

2) A reserve tank in the formation of RBC’s at time of necessity.

3) The major immunological function of spleen is that it acts as a filter for trapping

foreign particles that pass through the circulating blood. It brings about humoral and

cell mediated immunity.

3) Differentiate the primary and secondary lymphoid organs?

Primary lymphoid organ:

Primary lymphoid organs are the major site of lymphopoiesis. Here , the

lymphoid stem cells proliferate, differentiate and mature into

immunocomponent cells in the absence of antigenic stimulation.

a) The thymus.

b) The bursa of fabricuis in birds.

c) Bone maarow in mammals are the primary lymphoid organs.

Secondary lymphoid organ:

The secondary lymphoid organs are concerned with immune reactions. In the

secondary lymphoid organs the lymphocytes are made functional.

Here the cells are exposed to antigens and they produce antibodies or sensitized

cells. The secondary lymphoid organs are small and poorly developed at birth an

they grow progressively with age.

The secondary lymphoid organs include:

a) Lymph nodes.

b) Spleen.

c) MALT.

a) Peyer’s patches.

b) Tonsils.

4) Differentiate between T and B lymphocytes?

T-Lymphocytes: The mononuclear, no granular leukocyte that matures in thymus and

then brings about cell mediated immunity is called T lymphocytes.

1) Erythrocyte receptors.

2) T cell antigen receptors (TCR).

3) The Ia protein receptors.

4) Inter leukin receptors.

a) T helper cells (TH cells).

b) T suppressor cells (TS cells).

c) T cytotoxic cells (TC cells) or T killer cells (TK cells).

d) T delayed type hypersensitivity cells (TD cells).

B-Lymphocytes: The lymphocyte that matures in bursa of fabricius or bone marrow

and that brings about humoral immunity is called B lymphocyte.

The B lymphocyte has the following surface markers:

1) Ia protein.

2) Fc receptors.

3) CR1 and CR3 receptors.

4) Surface immunoglobulins.

5) Write about lymphocytic traffic?

The lymphocytes that enter the blood from the primary lymphoid organs

circulate through the secondary lymphoid organs namely lymph nodes, spleen.

Etc. and circulate back to the blood via.

The lymphatic system to be recirculated in the very same pathway. This

continuous process of circulation and recirculation of lymphocytes is referred as

lymphocytic traffic.

6) What is cell mediated immune response?

The resistance against infection produced by the sensitized lymphocytes is called

cell- mediated immunity.

Here antibodies are not produced. But specific lymphocytes are triggered against

microbes and the microbes are disposed.

In cell-mediated immunity the participation of T-Lymphocytes and macrophages

is predominant.

Cell-mediated immunity gives adequate protection against viruses, fungi,

protozoa and certain bacteria. It does not give protection against cocci.

The lymphokines recruit and draw macrophage to the site of infection and the

microbe is destroyed by the macrophages.

7) Write about the humoral immunity?

Immunity mediated by antibodies produced in the humors or body fluids such as

plasma or lymph is known as humoral immunity.

In this, specific antibodies are produced in response to specific antigen stimulus.

Ultimately the antigen (microorganisms) may be clumped, their toxicity may be

neutralized and their phagocytosis may be facilitated.

Active humoral immunity sets in only after a period known as latent period or lag

period during which the immunologic machinery is getting ready to produce

antibodies.

10 MARKS:-

1) Discuss the organization of the immune system?

The organs concerned with immune reaction are called lymphoid organs. They

contain lymphoid cells (lymphocytes).

The lymphoid organs and the lymphoid cells constitute the lymphoid system.

The lymphoid organs are two types:-

a. The primary lymphoid organs (central).

b. The secondary lymphoid organs (peripheral).

Primary lymphoid organ:

Primary lymphoid organs are the major site of lymphopoiesis. Here , the

lymphoid stem cells proliferate, differentiate and mature into

immunocomponent cells in the absence of antigenic stimulation.

a) The thymus.

b) The bursa of fabricuis in birds.

c) Bone maarow in mammals are the primary lymphoid organs.

Secondary lymphoid organ:

The secondary lymphoid organs are concerned with immune reactions. In the

secondary lymphoid organs the lymphocytes are made functional. Here the cells

are exposed to antigens and they produce antibodies or sensitized cells. The

secondary lymphoid organs are small and poorly developed at birth an they grow

progressively with age.

The secondary lymphoid organs include:

a) Lymph nodes.

b) Spleen.

c) MALT.

Peyer’s patches.

Tonsils.

2) Give detailed account on lymphocytes?

Lymphocytes are mononucleate, non granular leukocytes of lymphoid tissue,

participating in immunity.

They are lymphocytes are of three types. They are

1) B lymphocytes.

2) T lymphocytes.

3) Null cells.

T-Lymphocytes: The mononuclear, nongranular leucocyte that matres in thymus and

then brings about cell mediated immunity is called T lymphocytes.

1) Erythrocyte receptors.

2) T cell antigen receptors (TCR).

3) The Ia protein receptors.

4) Inter leukin recetors.

T helper cells (TH cells).

T suppressor cells (TS cells).

T cytotoxic cells (TC cells) or T killer cells (TK cells).

T delyed type hypersensitivity cells (TD cells).

B-Lymphocytes: The lymphocytes that matures in bursa of fabricius or bone marrow and

that brings about humoral immunity is called B Lymphocyte.

The B lymphocyte has the following surfacemarkers:

i. Ia protein.

ii. Fc receptors.

iii. CR1 and CR3 receptors.

iv. Surface immunoglobulins.

Null cells:-null cells are lymphocytes with cytotoxic properties. They are

neither B cells nor T cell.

They are intermediate between T and B cells.

They form the third population cells (TPC). They

form less than 3%.

There are two types of null cells, namely

1) Natural killer cells.

2) Killer cells.

Antigen presenting cells:-

The cells which process and transfer the antigen to lymphocytes are called antigen

presenting cells.

Lymphocytic traffic:-

The lymphocytes that enter the blood from the primary lymphoid organs circulate

through the secondary lymphoid organs namely lymph nodes, spleen. Etc. and circulate

back to the blood via. The lymphatic system to be recirculated in the very same

pathway. This continuous process of circulation and recirculation of lymphocytes is

referred as lymphocytic traffic.

4) Write about T lymphocytes?

T-Lymphocytes: The mononuclear, nongranular leucocyte that matres in thymus and

then brings about cell mediated immunity is called T lymphocytes.

Erythrocyte receptors.

T cell antigen receptors (TCR).

The Ia protein receptors.

Inter leukin recetors.

o T helper cells (TH cells).

o T suppressor cells (TS cells).

o T cytotoxic cells (TC cells) or T killer cells (TK cells).

o T delyed type hypersensitivity cells (TD cells).

5) Write about B cells activation and its function?

B-Lymphocytes: The lymphocyte that matures in bursa of fabricius or bone marrow

and that brings about humoral immunity is called B lymphocyte.

The B lymphocyte has the following surfacemarkers:

1) Ia protein.

2) Fc receptors.

3) CR1 and CR3 receptors.

4) Surface immunoglobulins.

6) Give detailed account on antigen presentation?

The cells which process and transfer the antigen to lymphocytes are called

antigen presenting cells.

Three groups of antigen presenting cells are available in the immune system.

They are

a) Macrophages.

b) Dendritic cells.

c) Langherhans cells.

Macrophages are large mononuclear cells.they live in the tissues.

They are strongly phagocytic. They contain class I and II MHC molecules and

receptors of Fc and complement.

Dendritic cells are present in the spleen and lymph nodes. They have long

processes.

They contain Fc receptors and class II MHC molecules.

IMMUNOLOGY

UNIT-3

2 MARKS:-

1) What is mean by antigen?

A substance that can produce a specific immune response when it is introduced into the

tissues of an animal and that can react specifically with antibodies or sensitized cells is

known as an antigen.

2) What is mean by immunogenicity?

The ability of a material to induce an immune response is referred to as immunogenicity

and such materials are known as immunogens.

3) Comment on epitopes and paratopes?

The part of the antigens with which the antibody reacts is known as the epitops or

antigenic determinants.

The portion of the antibody molecule that binds to the epitope is called the paratope.

4) What is mean by haptens?

Haptens is called an incomplete antigens. Haptens can combine with an antibody but

cannot initiate an immune response, not immunogenic by itself unless it is bound to a

carrier before introduction into the body.

5) Comment on vaccines?

Vaccine is an antigenic preparation of microorganisms such as bacteria, viruses or

rickettsiae administrating for prevention treatment of infectious disease.

6) What is mean by immunoglobulins?

Immunoglobulins are immunologically active serum proteins formed to an antigen and

react specifically with that antigen.

5 MARKS:-

1) Describe the basic structure of immunoglobulins?

Immunoglobulins are immunologically active serum proteins formed to an

antigen and react specifically with that antigen.

They are briefly represented as Ig. They are commonly called antibodies (Ab).

Immunoglobulins are immunological missles produced by the body. They are

found in the serum, body fluids and tissues.

Rodney Porter (1962) proposed the basic structure of immunoglobulin.

Immunoglobulin is a glycoprotein.

It is a Y- shaped or T- shaped molecule.

It is made up of 4 polypeptide chains.

Of these, two chains are short they are called light chains (L- chains) and they are

identical.

The other two chains are longer; they are called heavy chains (H- chains) and

they are identical.

2) Describe the function of immunoglobulins?

The main function of the immunoglobulins is protection of the body against the

invading microorganisms. The protective role is carried in the following ways:

1. Agglutination of antigens.

2. Precipitation if antigens.

3. Neutralization of antigens.

4. Lysis of the antigens.

5. Opsonisation.

6. Tissue fixation.

7. Phagocytosis.

8. Chemotaxis.

9. Activation of mast cells and basophils.

3) Explain the function of IgA?

IgA is an antibody. IgA is found in serum. IgA is a glycoprotein. It is Y- shaped. It is

of two types, namely serum IgA and secretory IgA, secretory IgA is seen in the

external seromucous secretions of the repiratory, gastro intestinal and

urinogenital tracts.

IgA is the second in abundance among the immunoglobulins next to IgA.

Two cubclasses of IgA exist namely IgA1 and IgA2.

1) Serum IgA.

2) Secretory IgA.

4) Explain the structure of IgG with the neat diagram?

IgG is immunoglobulinG. It is an antibody. It is a glycoprotein. It is Y-shaped.

It is a relatively stable, four polypeptide chained molecule formed of 2 light

chains and 2 heavy chains.

The light chain consists of a single constant domain and a single variable domain.

The heavy chain consists of 4 domain namely a single variable domain and 3

constant domain.

IgG is of greatest amount in internal body fluids and is produced particularly

during the secondary immune reponse.

IgG has half life of 25 days.

5) Explain the structure of IgM?

IgM is an antibody. It is the largest of the immunoglobulins. It is often referred

as the macroglobulin because of its high molecular weight. It is Y-shaped.

They are polymers of usually 5 molecules each with 4 polypeptide chains.

The polymerization of these molecules occurs in the presence of joining chain as

in the case of secretory IgA. The J chain is holding the 5subunits together at Fc

region and stabilizes the Fc sulfhydryl groups.

There is no subclass for IgM.

The sedimentation coefficient of this pentamer is 19S.

Phylogenetically IgM is the most primitive immunoglobulin present in all

vertebrates from lampreys inwards.

10 MARK:-

1) Give a brief account of the essential factors for antigenicity?

1. SIZE:- The molecular size of an antigen has a direct relation to antigenicity.

2. CHEMICAL NATURE:- Most of the naturally occurring antigens are proteins and

polysaccharides and these antigens are found to be comparatively more antigenic

than lipids and nucleic acid.

3. SOLUBILITY:- The nonantigenicity of synthetic polymers is also attributed to their

insolubility in body fluids and any substance which is not converted to soluble forms

by tissues enzymes are also not antigenic.

4. FOREIGNNESS:- To be antigenic, the macromolecule must come from a foreign

source. Antigens from related species are less antigenic than that of unrelated

species and antigens from members of the same species are less antigenic than that

of other species.

2) What are vaccines? Describe the different types of vaccines?

Vaccine is an antigenic preparation of microorganisms such as bacteria, viruses

or rickettsiae, administered for prevention treatment of infectious diseases.

The vaccines are classified into the following types:

16) Homologous vaccines.

17) Heterologous vaccines.

18) Cellular vaccines.

19) Sub-cellular vaccines.

20) Attenuated vaccines.

21) Inactivated vaccines.

22) Toxoid vaccines.

23) Sub-unit vaccines.

24) Recombinant vaccines.

25) Mixed or combined vaccines.

26) Autogenous vaccines.

27) Freeze dried vaccines.

28) Antiviral vaccines.

29) Antibacterial vaccines.

30) Anti-rickettsial vaccines.

3) Write an essay on the classification and distribution of immunoglobulins?

Immunoglobulins are immunologically active serum proteins formed to an

antigen and react specifically with that antigen.

They are briefly represented as Ig. They are commonly called antibodies (Ab).

Immunoglobulins are immunological missles produced by the body. They are

found in the serum, body fluids and tissues.

Rodney Porter (1962) proposed the basic structure of immunoglobulin.

Immunoglobulin is a glycoprotein.

It is a Y- shaped or T- shaped molecule.

It is made up of 4 polypeptide chains.

Of these, two chains are short they are called light chains (L- chains) and they are

identical.

The other two chains are longer; they are called heavy chains (H- chains) and

they are identical.

There are two types of light chains, namely Kappa (k) and lambda () based on the

structure and amino acid sequence.

The heavy chains are of 5 types. Theyare the following;

1. Gamma

2. Alpha.

3. Mu.

4. Delta.

5. Epsilon.

IgG:- IgG is immunoglobulinG. It is an antibody. It is a glycoprotein. It is Y-shaped.

It is a relatively stable, four polypeptide chained molecule formed of 2 light

chains and 2 heavy chains.

The light chain consists of a single constant domain and a single variable domain.

The heavy chain consists of 4 domain namely a single variable domain and 3

constant domain.

IgG is of greatest amount in internal body fluids and is produced particularly

during the secondary immune reponse.

IgG has half life of 25 days.

IgA:- IgA is an antibody. IgA is found in serum. IgA is a glycoprotein. It is Y- shaped. It is

of two types, namely serum IgA and secretory IgA, secretory IgA is seen in the

external seromucous secretions of the repiratory, gastro intestinal and

urinogenital tracts.

IgA is the second in abundance among the immunoglobulins next to IgA.

Two cubclasses of IgA exist namely IgA1 and IgA2.

i. Serum IgA.

ii. Secretory IgA.

Ig M:-

IgM is an antibody. It is the largest of the immunoglobulins. It is often referred

as the macroglobulin because of its high molecular weight. It is Y-shaped.

They are polymers of usually 5 molecules each with 4 polypeptide chains.

The polymerization of these molecules occurs in the presence of joining chain as

in the case of secretory IgA. The J chain is holding the 5subunits together at Fc

region and stabilizes the Fc sulfhydryl groups.

There is no subclass for IgM.

The sedimentation coefficient of this pentamer is 19S.

Phylogenetically IgM is the most primitive immunoglobulin present in all

vertebrates from lampreys inwards.

IMMUNOLOGY

UNIT-4

2 MARKS:-

1) Comment on antigen-antibody reaction?

The interaction between antigen and antibody is called antigen- antibody reaction.

2) What is mean by immune complex?

When antigen and antibody are brought together, the antibodies bind with antigen to

form a complex molecule called immune complex or antigen-antibody complex.

3) Define agglutination?

Agglutination is an antigen-antibody reaction where the antibody of serum causes the

cellular antigens to adhere to one another to form clumps.

It is the clumping of a particular antigen and its antibody.

4) What is mean by opsonization?

Opsonization is the process by which a particulate antigen becomes more susceptible to

phagocytosis by combination with an opsonin.

5) Define immunofluorescence?

When antibodies are mixed with fluorescent dyes such as fluoresce in or

rhodamine, they emit radiation. This phenomenon of emitting radiation by

antibodies labeled with fluorescent dyes is called immunofluorescence.

5 MARKS:-

1) Give an account on antigen – antibody reaction?

The interaction between antigen and antibody is called antigen- antibody

reaction.

a) Immune complex.

b) Specificity of Ag-Ab reaction.

c) Binding site of antigen and antibody.

d) Binding forces of antigen and antibody.

e) Avidity.

f) Bonus effect.

g) Cross reaction.

2) Describe the classical pathway of complement system?

Classical pathway is a simple step-wise reaction brought about by the activation

of complement system.

The classical pathway is activated by antigens-antibody complex, gram negative

bacteria and animal viruses.

The complement components involved in the classical pathway are 11*

components, namely C1q, C1r, and C1s. the component C1 ha 3 subunits.

The 11 components of the classical pathway react in the following sequence;

C1q, C1r, C1s, C4, C2, C3, C5, C6, C7, C8, C9.

The activating agent such as antigen-antibody complex interacts with the first

components of the complement C1.

3) Give an account on ELISA?

ELISA is an immunological technique used for the quantitative determination of

the concentration of certain antigens and antibodies.

The ELISA technique was first introduced in 1970 by Engval and Perlmann.

The antibodies are absorbed to a solid support, a polystyrene micro titer plate.

A chromomeric substance for the enzymes is added and colored product

generated is measured.

ELISA is used to detect a variety of antibodies and antigens such as plant and

animal hormones, toxins, and viruses. It is a successful technique for detecting

AIDS.

4) Give an account on immunofluoresence?

When antibodies are mixed with fluorescent dyes such as fluoresce in or

rhodamine, they emit radiation. This phenomenon of emitting radiation by

antibodies labeled with fluorescent dyes is called immunofluorescence.

Application of immunofluoresence.

Methods of immunofluoresence.

1. Direct method.

2. Indirect method.

3. Sandwich method.

5) Give a detail account on radioimmunoassay?

Radioimmunoassay is an immunological technique using radioactive substances

for the quantitative measurement and identification of antigens, antibodies,

hormones, drugs etc.

This technique uses the competition between radiolabel led and unlabelled

substances in an antigen-antibody reaction to determine the concentration of

the unlabelled substances.

10 MARKS:-

1) Give an account of the alternative pathway of complement system?

The activation of complement C3 without the prior participation of C1, C4, and

C2 is called alternative pathway.

The alternative pathway was discovered by Pillemer in 1954.

Alternative pathway is a step wise reaction of the complement system to bring

about the destruction of microbes in the body.

The alternative pathway is activated by aggregated antibodies IgA or IgG

lypopolysaccharide, bacterial endotoxin and yeast.

The alternative pathway is independent of the Fc fragment of antibodies.

About 6 complement components are involved in the alternative pathway. They

are C3, B, D, P, H and I.

The alternative pathway does not involve components C1, C4, C2.

In this pathway C3 is the starting component and it is activated without the

activation of C1, C4, and C2.

2) What is precipitin reaction? Mention its application?

Precipitation is an immunological reaction between a soluble antigen and

antibody resulting in the formation of an insoluble precipitate. The reaction is

also called precipitin reaction. The precipitin reaction is the basic principle used

in the following technique:

1. VDRL test for syphilis.

2. Simple double immunodiffusion.

3. Single radial immunodiffusion.

4. Immunoelectrophoresis.

5. Countercurrent immunoelectrophoresis.

6. Rocket immunoelectrophoresis.

3) Give detailed account on ELISA?

ELISA is an immunological technique used for the quantitative determination of

the concentration of certain antigens and antibodies.

The ELISA technique was first introduced in 1970 by Engval and Perlmann.

The antibodies are absorbed to a solid support, a polystyrene micro titer plate.

A chromogenic substance for the enzymes is added and colored product

generated is measured.

ELISA is used to detect a variety of antibodies and antigens such as plant and

animal hormones, toxins, and viruses. It is a successful technique for detecting

AIDS.

4) What is agglutination? Explain the different techniques?

Agglutination is an antigen-antibody reaction where the antibody of serum

causes the cellular antigens to adhere to one another to form clumps.

It is the clumping of a particular antigen and its antibody.

The particulate antigens include RBC, platelets, lymphocytes, bacteria, viruses,

etc.

The principle of agglutination is used in the following fields:

1. ABO blood typing.

2. Rh blood typing.

3. Widal test.

4. Well-felix reaction.

5. Coomb’s test.

6. Brucella agglutination.

IMMUNOLOGY

UNIT-5

2MARKS:-

1) Define Hypersensitivity

Hypersensitivity is defined as the violent reaction of the immune system leading to

severe symptoms and even death in a sensitized animal when it is re-exposed to the

same antigen for the second time. It is also called allergy.

2) What are the Factors causing hypersensitivity?

Hypersensitivity is caused by numerous factors, these factors causing allergy are called

allergens. They may two factors;

a) Extrinsic factor(introduced into the body from outside)

b) Intrinsic factor(factors which remain within the body). They are the following:

1) Drugs.

2) Airborne particles.

3) Food stuffs.

4) Infectious organisms.

5) Blood transfusion.

3) What are the Types of hypersensitivity?

Hypersensitivity is classified in two ways. They are;

1) Based on the time taken for the reaction.

a) Immediate hypersensitivity.

b) Delayed hypersensitivity.

2) Based on the different mechanisms of pathogenesis.

a) Type I- Anaphylatic hypersensitivity.

b) Type II- Antibody-dependent cytotoxic hypersensitivity.

c) Type III- Immune complex-mediated hypersensitivity.

d) Type IV-Cell-mediated hypersensitivity.

e) Type V- Stimulatory hypersensitivity.

4) What is mean by Erythroblastosis foetalis?

Erythroblastosis foetalis is a haemolytic disease caused by the reaction of Rh antigen

and Rh antibody.

It occurs in the Rh+ baby developing in an Rh- mother.

The Rh antibody involved in their reaction belongs of IgG type. It ia an isoimmune

reaction.

5) What is Mantoux reaction?

Tuberculin or mantoux reaction is type IV hypersensitivity. It is due to the interaction of

sensitized T-cells and tuberculin bacterium. The tuberculin reaction is characterized by

local erythema and induration.

6) Define MHC.

Major histocompatibility complex refers to a cluster of genes responsible for immune

response, transplantation antigens and proteins of the complement system.

The histocompatibility antigens are classified into four types.

a) Class 1 molecule.

b) Class 2 molecule.

c) Class 3 molecule.

d) Class 4 molecule.

5 MARKS:-

1) Write notes on:-

a) Atopic allergy:

The atopic allergy is hereditary and can be seen in only the hereditarily predisposed

individuals for hypersensitivity.

b) Cutaneous anaphylaxis:

It is classified into active and passive cutaneous anaphylaxis.

c) Arthus reaction:

Arthus reaction is a local immune complex reaction produced on the skin by the

intradermal injection of non-toxic forgein substances like horse serum, egg albumin

etc. into rabbits or guinea pigs.

d) Serum sickness:

Serum sickness is an immune complex disease caused by the enormous amount of

forgein serum, such as antidiptheria antiserum, antitetanus antiserum.

2) What is precipitation? Describe the immunological technique designed on

the principle of precipitation.

Precipitation is an immunological reaction between a soluble antigen and antibody

resulting in the formation of an insoluble precipitate. The reaction is called precipitin

reaction. The precipitin reaction is the principle used in the following technique;

1. VDRL test for syphilis.

2. Simple double immunodiffusion.

3. Single radial immunodiffusion.

4. Immunoelectrophoresis.

5. Countercurrent immunoelectrophoresis.

6. Rocket immunoelectrophoresis.

3) What is radioimmunoassay? Describe the procedure and its application.

Radioimmunoassay is an immunological technique using radioactive substances for the

quantitative measurement and identification of antigens, antibodies, hormones, drugs,

etc.

4) What is agglutination? Describe the typing of ABO and Rh blood grouping.

Agglutitation is an antigen antibody reaction where the antibody causes the cellular

insoluble antigens to adhere to one another to form clumps.

1) ABO blood typing.

2) Rh blood typing.

3) Widal test.

4) Well-felix reaction.

5) Coomb’s test.

6) Brucella agglutination.

5) Describe the structure of MHC.

Major histocompatibility complex refers to a cluster of genes responsible for immune

response, transplantation antigens and proteins of the complement system.

The histocompatibility antigens are classified into four types.

e) Class 1 molecule.

f) Class 2 molecule.

g) Class 3 molecule.

h) Class 4 molecule.

Major histocompatibility complex of man is called HLA(human leucocyte antigen). It

is a cluster of structural genes responsible for the production of antigens located on

the nucleated cells and components of complements.

10 MARKS:

1) What is hypersensitivity? Classify it with an example.

Hypersensitivity is defined as the violent reaction of the immune system leading

to severe symptoms and even death in a sensitized animal when it is re-exposed

to the same antigen for the second time. It is also called allergy.Hypersensitivity

is caused by numerous factors, these factors causing allergy are called allergens.

They may two factors;

Extrinsic factor (introduced into the body from outside)

Intrinsic factor (factors which remain within the body)They are the following:

Drugs.

Airborne particles.

Food stuffs.

Infectious organisms.

Blood transfusion.

Hypersensitivity is classified in two ways. They are;

1. Based on the time taken for the reaction.

Immediate hypersensitivity.

Delayed hypersensitivity.

2. Based on the different mechanisms of pathogenesis.

Type I- Anaphylatic hypersensitivity.

Type II- Antibody-dependent cytotoxic hypersensitivity.

Type III- Immune complex-mediated hypersensitivity.

Type IV-Cell-mediated hypersensitivity.

Type V- Stimulatory hypersensitivity.

2) Give an account of immune complex mediated hypersensitivity.

Type III: immune complex mediated hypersensitivity: the hypersensitivity

produced by the antigen-antibody complex is called immune complex mediated

hypersensitivity.

Mechanism of immune complex mediated hypersensitivity.

1) Arthus reaction.

2) Serum sickness.

3) Write notes on:

a) Type II hypersensitivity: type Ii hypersensitivity is due to the interaction

of antibodies and cell associated antigens.

Types of cytotoxic hypersensitivity

1) Isoimmune reaction.

2) Autoimmune reaction.

Isoimmune reaction:

a) Transfusion reactions.

b) Erythroblastosis foetalis.

c) Transplant rejection reaction.

Autoimmune reaction:

a) Autoimmune haemolytic anaemia.

b) Autoimmune thrombocytopaenic purpura.

c) Autoimmune thyroiditis.

d) Autoimmune glomerulonephrities.

Mechanism of cytotoxic reaction.

1) Phagocytosis.

2) Lysis.

3) Killing.

b) Type III hypersensitivity: Type III: immune complex mediated hypersensitivity: the hypersensitivity produced by

the antigen-antibody complex is called immune complex mediated hypersensitivity.

Mechanism of immune complex mediated hypersensitivity.

a. Arthus reaction.

b. Serum sickness.

Mechanism of immune complex mediated hypersensitivity.

4) Give an account of delayed type hypersensitivity reaction.

When the immune reaction manifest slowly from 24 hours to 72 hours, the hypersensitivity is

called delayed type.

Type IV hypersensitivity is caused by the interaction betweenantigens and sensitized T cells.

This reaction leads to inflammatory reaction and causes tissue damage.Mechanism of type IV

hypersensitivity

1) Tuberculin reaction.

2) Contact dermatitis.

5) What is transplantation? Describe the types of transplantation.

Transplantation refers to the implantation of a tissue from one individual to another.

The implanted tissue is called graft or transplant.

The animal from which the graft is taken is called donor and the animal in which the graft

is placed is called recipient or host.

In transplantation cells or tissue or organs are transplanted. The structure used for

transplantation includes individual cells, tissue, skin, kidney, heart, eye, etc.

Transplantation immunology refers to the study of the response of the immune system

when a graft is implanted on an animal.

The graft is classified into four types. They are the following:

1. Autograft

2. Syngraft

3. Allograft

4. xenograft