The Immune System
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The Immune System I. Specific Immunity A. Humoral Mediated: (B-Cell immunity; Free Ig’s) Antibodies react to bacteria by: 1. Binding directly with bacterial toxins to neutralize them 2. Coat bacteria to enhance the phagocytosis be non-specifics components (monocytes, etc.,). Immunoglobulin subclass: IgG, IgA, IgM, IgD, & IgE
description
The Immune System. I. Specific Immunity A. Humoral Mediated: (B-Cell immunity; Free Ig’s) Antibodies react to bacteria by: 1. Binding directly with bacterial toxins to neutralize them 2. Coat bacteria to enhance the phagocytosis be non-specifics components (monocytes, etc.,). - PowerPoint PPT Presentation
Transcript of The Immune System
The Immune SystemI. Specific Immunity
A. Humoral Mediated:(B-Cell immunity; Free Ig’s)Antibodies react to bacteria by:1. Binding directly with bacterial toxins to neutralize them
2. Coat bacteria to enhance the phagocytosis be non-specifics components (monocytes, etc.,).
Immunoglobulin subclass: IgG, IgA, IgM, IgD, & IgE
The Immune SystemI. Specific Immunity
B. Cell Mediated:( T-cell immunity; membrane receptors)Viruses, parasites, fungi, etc., are reacted by:1. Helper - T2. Cytotoxic - Tcells3. Macrophages4. Tranfer factor
5. Cytokines (lymphokines/interleukins)II. Non-specific Immunity
Table 15.2 Phagocytic Cells and Their LocationsPhagocyte:NeutrophisMonocytesTissue macrophages (histiocytes)
Kupffer cellsAlveclar macrophagesMicrogia
Location:Blood & all tissuesBlood & tissuesAll tissues ( including spleen, lymph nodes, bone marrow)LiverLungsCentral nervous system
Development of the Immune System
Hematopoietic stem cells
Yolk sac/Bone
Lymphoid stem cells
T-lymphocytes
Thymus
Sensitized lymphocytes Cellular Immunity
Bone
B-lymphocytes
Plasma cells Humoral Immunity
EtrythrocytesGranulocytes
MonocytesMegokaryocytes
Immunology ReviewAntigen
macrophage
Immunoglobulins(immediate hypersensitivity)
Plasma Cells
Transfer factorDelayed hypersensitivity
Advanced lymphcytes
Immune System
T-cellsCellularthymus
B-cellsHumoralBone(Gut associated lymphoid tissue)
Table 15.5 Immunology ReviewImmunoglobulins
IgC most abundant Ig of internal body fluids, particularly extravascular. Where they combat micro-organisms and their toxins
IgA major Ig insero-mucus secretions where it defends external body surfaces
IgM very effective agglutinator; produced early in immune response - effective first line of defense vs. bacteraemia
IgD present on lymphocytes surface of newbornIgE raised in parasitic infections. Responsible for
symptions of atopic allergy
Table 15.5 Immunology ReviewImmunoglobulins
Antibody model proposed by R.E. Porter withtwo heavy and two light polypeptide chains held by interchain disulphide bonds
X
X
SS
SS
light
light
heavy
heavy
Antigenbindingsites
SS
Birth
Mother -3 0 6 12 18
Infant
IgM
IgG
IgA, IgD, IgE
% A
dult
Lev
el
0
50
100
Age in monthsDevelopment of serum immunoglobulin levelsin the human.
The Complement SystemMechanism of Action
1. IgG & IgM-antigen complexes bind with C-1 to activate the enzyme system.
2. Activated C-1 converts C-4 into C-4a & C-4b.3. C-4b binds to the antigen’s membrane (is
fixed) and causes theconversion of C-2 into C-2a & C-2b.
4. C-2a attaches to C-4b and causes the cleaving of C-3 into C-3a & C-3b. The C-3b attaches to the complex while C-3a is secreted.
The Complement SystemMechanism of Action
5. Activated C-5 through C-9 become fixed to the antigen & create large pores in the membranes of the antigens allowing H20 influx. The cells (bacterial) swell and burst.
6. C-3a & C-5a produce chemotaxic substances which:A) attract phagocytes
B) cause opsonization-stimulates phagocytes C) cause release of histamine from mast cells
The Complement System(continued)
Summary1. Recognition: (C-1)2. Activation: (C4, C2 + C3)3. Attack: (C5 -C9)
Development of the T-cell SystemLymphocyte precursors originate in the yolk sac and migrate into
the fetus. The lymphoid stem cells then migrate to the thymus under the influence of an “attraction factor.” The cells then become “programmed” and become immunocompetent.
PUTATIVE PROCESS:1. Thymic hormones thyopoietin I & II transform the stem cells
into T-cells in the thymic cortex2. Thymic hormone thymosin promotes the maturation of T-cells
in the thymic medulla & other lymphoid tissue.3. Some of the T-cells enter the blood and travel to other
lymphoid tissues and establish colonies (germinal centers) where they divide by clonal growth.
T-cell receptor
Helper T-cellKiller T-cell
Foreign antigenCD4coreceptor
Antigen presenting
cell
Target cell
Class-2 MHCmolecule
Class-1 MHCmolecule
CD8coreceptor
Figure 15.18 Coreceptors on helper and killer T cells .A foreign antigen is presented to T lymphocytes in association with MHC Molecules. The CD4, on helper T cells and CD8 corecepters on killer T cells, permit each type of T cell to interact only with a specificclass of MHC molecule
HIV life cycle: Viral Infection
CD4
Viral RNAReverse transcriptase Reverse
Transcription
AttachmentPenetration
Integration
Proviral DNA
Cellular DNA
Cell Nucleus
Free Virus
HIV life cycle:phase of viral expression
Viral proteins
Transcription
Budding
Packagingtranslation
Proviral DNA
Viral RNA
Free Virus
Cell Nucleus
Genomic RNAsplicing
Acquired Immune Deficiency Syndrome (AIDS)
Caused by Human Immunodeficiency Virus (HIV)Classes: 1. Oncornaviruses (cause tumors, but not AIDS) a. HTLV-1
b. HTLV-22. Cytopathic Virus (Lenti-viruses) cause AIDS
a. HIV-1 worldwideb. HIV-2 less pathogenic (geographically restricted)
Acquired Immune Deficiency Syndrome (AIDS)
(continued)Modes of transmissions:1. Sexual contact with an HIV-infected
person2. Transfusion of HIV contaminated blood3. In utero from infected mother to baby4. Injected drug use5. Mucocutaneous exposure (one case from
kissing)
Acquired Immune Deficiency Syndrome (AIDS)
(continued)Risk of HIV Transmission:A person is at risk of HIV infection anytime
s/he comes into contact with the following fluids of an infected individual:
BloodSemenVaginal fluidBreast milk
Table 1 Body Fluids to which Universal Precautions Apply In Relationship to
“Bloodborne” Pathogens
BloodSerum/plasmaSemenVaginal secretionsCerebrospinal fluidVitreous fluidHuman Breast Milk
Synovial fluidPleural fluidPericardial fluidPeritoneal fluidAmniotic fluidWound exudates
Table 2 Body Fluids to which Universal Precautions Apply If Containing Visible Blood In Relationship to “Bloodborne” Pathogens
SalivaFeces Vomitus Urine Nasal secretions Sputum Sweat Tears
Table 3 Handling of Medical Devices /Equipment for Reuse
Use of Device:Contact with skin
Contact with mucous membrane
Penetrate skin
Method of Reprocessing:Decontaminate only use intermediate or low-level germicide or simple wash with soap and waterDecontaminate, then preferably sterilize at a minimum do high level disinfection by soaking 10 - 20 minutes in an EPA approved chemical agentDecontaminate and sterilize by cold sterilization (12) or preferably by heat steam or gas following the recommendations of the sterilizer
Florida HIV Statistics as of 1/1/95U.S.A. 1 in 250 est. to be HIV+ FLA. 1 in 100 est. to be HIV +Dade 1 in 40 est. to be HIV+Orlando 1 in 20 est. to be HIV+HIV leading cause of death among women aged 15 - 25 in USA1 women infected every 1 -2 minutes Worldwide1 women dies due HIV every 2 minutes
AIDS/HIV Statistics as of 1/1/9518,000 children have lost their mothers to HIV# of teens contracting HIV doubles every 14 months6,500,000 teenagers contract a STD in USA each year30,000 HIV infected teens in USA 1/1/94
FLA is: #1 Heterosexual trasnsmission #2 Injectable drug transmission #2 Teenage & pediatric cases #3 Total AIDS cases
AIDS/HIV Statistics as of 1/1/95AIDS leading Counties CitiesDade 13,654 MiamiBroward 6,909 Ft. LauderdalePalm Beach 3,775 West Palm BeachHillsborough 2,585 TampaDuval 2,225 JacksonvilleOrange 2,249 OrlandoTotal cases 43,242 Fla 401,749 USA
RNA or Thymic hormone
Lymphokine
Lymphokine
Lymphokine
Characteristics of LymphokinesB-cell: Ig helper effect
B-cell: No Ig Suppressor effect
T-cell: Blastogenesis
Activiated marcophageMacrophage migration inhibition Chemotoxis
Other cells: Viral resistance Cytotoxic inactivation
Macrophage:
