Types of Immunity

Case Study

Jagraj Brar

Basics

Antigen- foreign substance in the body Antibody- fight antigens:

IgA IgD IgE IgG IgM

Alpha Delta Epsilon Gamma Mu

10 Antigen binding sites.

4 antigen binding sites

2 antigen binding sites

Introduction

Immunity is the ability of the body to resist becoming infected upon exposure to any antigen.

Some various types include:-Passive immunity (Artificially & Naturally)

-Herd immunity

-Active immunity (Artificially & Naturally):Innate Acquired-Cellular immunity -Cellular immunity -Humoral immunity -Humoral immunity

Passive Immunity

Naturally Acquired- Occurs during

pregnancy,

- Certain antibodies are passed from the maternal into the fetal bloodstream

- IgG can cross the placenta

Artificially Acquired-A short-term immunization

-The injection of antibodies, that are not produced by the recipient's cells.

Herd Immunity

Protection of any one individual from a disease following the principal, that everyone around him/her is immune

Hence no direct exposure to the disease.

Virologists have found that when a certain percentage of a population is vaccinated, the spread of the disease is effectively stopped. This critical percentage, called the herd immunity threshold.[1]

[1] Jamison DT, Breman JG, Measham AR (editors) (2006). "Chapter 4: Vaccine-preventable Diseases". Priorities in Health: Disease Control Priorities Companion Volume. World Bank Publications.

Active Immunity

Naturally Acquired- Expose to live pathogen

- Development of disease

- Immunity develops due to primary immune response

2 Types:

Innate & Acquired

Artificially Acquire

-Vaccine containing antigen

-Simulates the primary immune response

-No development of disease

Active ImmunityInnate

Naturally occurring Non-Specific Immediate response Can kill many microrganisms at a time Present at birth 2 types:-Humoral-Cell Mediated

Humoral immunity(Innate)

1)Complement system

2)Interferons (prevent spread of virus)

3)Natural killer cells

MAC

Opsonization by C3b targets foreign

particles for phagocytosis

Membrane attack

complex

Interferon

Virally infected cell Non-viral infected cell

Blue= Interferon Coat

Cell Mediated (Innate)

1)Neutrophils

2)Monocytes

3)Macrophages

Active ImmunityAcquired

Specific antibodies are raised against the previous microrganism.

Can only kill microrganism one at a time. 2 Types:

Humoral – B Lymphocytes

Cell Mediated- T Lymphocytes

Humoral immunity(Acquired)

B-Lymphocytes Origin Function Types

Origin of B-Lymphocytes

The abbreviation "B", in B cell, originally stood for bursa of Fabricius in birds

Now stands for bone because in mammals, immature B cells are formed in the bone marrow

Functions of B-Lymphocytes

B-cells have IgM Antibody B-cell receptor will bind to one particular

antigen B-cell comes across antigen causes the B-

cell to receive a signal from T-helper cell to form:

Plasma B Cells OR Memory B Cells

Plasma B- Cells

Large B-cells Activated (already exposed to antigen) and

secreting large amounts of antibodies. Make microbes easy targets for phagocytes and

activation of complement system “Antibody Factories” Short lived cells which undergo apoptosis after

antigen is eliminated.

Memory B-Cells

Activated B-cells

Specific to the antigen encountered during the primary immune response

Cells are able to live for a long time and can quickly respond during a second exposure to the same antigen,

Hence the name Memory cells

c

major histocompatibility complex (MHC).

Cell Mediated Immunity(Acquired) T-Lymphocytes T=“Thymus” When come in contact with antigen, they release

cytokines which help convert t-cells into: 3 Types: Tc – Cytotoxic T Cells Th- Helper T Cells Ts- Suppressor T Cells

Clinical correlations

Autoimmune Diseases. T-cell disorders B-cell disorders Immunodeficiency (AIDS) SCID- Severe combined

immunodeficiency

Autoimmune diseases: Arise from an overactive immune response.

Body begins to attack substances and tissues that are normally present in the body

Can be restricted to certain organs or tissues or it can be in many places of the body.

Treatment is immunosupression- which is a medication which decreases the immune response.

Examples include: Lupus, Goodpastures etc.

Disorders of T cells: DiGeorge’s syndrome ABSENT, FEW OR ABNORMAL T-CELLS

Large deletion of chromosome 22.

Congenital thymic dysplasia

absence or hypoplasia of thymus, parathyroid glands

Symptoms include: heart defects, effects on facial appearance, and lack of or underdeveloped thymus and parathyroid glands.

DiGeorge’s syndromeHypertelorism MicrognathiaShort philtrumFish mouthAntimongoloid slantLow-set earsCleft palateHypocalcaemia

Treatment: Bone Marrow Transplant

Disorders of B cells: X-Linked Infantile Hypogammaglobulinemia Most severe B-cell immunodeficiency Defective BTK Gene: Tyrosine Kinase Symptoms: Decreased/Absent b-cells Decreased/Absent immunoglobulins Increased susceptibility to bacterial

infections Treatment: Bone Marrow Transplant.

SCID- Severe combined immunodeficiency

Disorders of lymphoid stem cells Defects in both humoral and cellular

mediated immunity T-cells & B-cells 1: 100,000 births Lack of lymphoid cells: thymus, peripheral

lymphoid organs Death due to infections at 1 yr of age

David Vetter: the BUBBLE BOY

References 1)"Active and Passive Immunity." Active and Passive Immunity. 2007. The

Columbia Electronic Encyclopedia, 6th ed. Copyright ©. 6 June 2009 <http://www.infoplease.com/ce6/sci/A0858765.html>.

2)"The Complement System." The Complement System. 22 Sept. 2007. 6 June 2009 <http://www.howstuffworks.com/framed.htm?parent=immune-system.htm&url=http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/Complement.html>.

3)Guyton, C., and John E. Hall. The Textbook of Medical Physiology. Vol. 11. Elsevier Inc.

4)Hull, Dr. "Immunity, types of." Night, Night! Dr. Hull's Common Sense Sleep Solutions. 06 June 2009 <http://www.drhull.com/EncyMaster/I/immunity.html>.

5) [1] Jamison DT, Breman JG, Measham AR (editors) (2006). "Chapter 4: Vaccine-preventable Diseases". Priorities in Health: Disease Control Priorities Companion Volume. World Bank Publications.

6) Dr. Prasad. Immune system classifications. Pre-Med 2- Physiology. 2008.