DEFENSE: IMMUNITY

 

8/3/87, RVSD 8/17/94, 14 Aug 00, 7 March 02, 12 Aug 02, 13 Aug 03, 16 Aug04, 17 Aug 05, 8 May 06, 15 Aug07

Fr: TFC, 2nd Ed, 437., Alcamo, pp547-581, TFC’s 7th: 454-472, 476-495, 8th: 458-481, Black’s 6th: 470-577, Bauman 2nd: 462-483

 

IMMUNE SYSTEM        Adaptive Immunity    either natural or by immunization

                                           Passive Immunity       natural through placenta and milk, or by gamma globulin injections

ANTIGENS: determinant sites = epitopes = haptens (grasp) (p 463)

 

LYMPHATIC SYSTEM (p 464)      System to cleanse organs with lymph, filter lymph, house immune cells

                                                             (P 466) lymph node structure

 

TWO COMPONENTS OF IMMUNE SYSTEM: Humoral and Cell-mediated

 

HUMORAL SYSTEM    B cells (first seen in bursa of Fabricius) found in all lymphoid tissues, 10% of circulating lymphocytes. B cells secrete antibodies, soluble, found in bodily fluids (humors)

                                          Serum carries antibodies in gamma globulin fraction

               electrophoresis separates into

                            POSITIVE (+):       gamma,    beta,              alpha,    album.   most NEGATIVE (-) 

 

ANTIBODY STRUCTURE (p 467) Illustrate IgG: neutralization, opsinozation, agglutination, precipitation (468)

 

ANTIBODIES: table: p 469

IgG:

80-85%

dimer

can cross placenta 

Ag binding, light, heavy chains, constant, variable regions,

compliment activating region

IgM

5-10%

pentamer

first to appear, highly effective agglultinators, microorganisms

ABO blood group antibodies

IgA

15 %

 

carries secretory component, allows

 secretion into saliva, tears, mucus, breast milk

IgD

0.2%

 

cannot cross placenta, surface of B, cells, do not fix complement

IgE

0.002%

 

bound to mast cells, triggers release of histamine, anaphylactic rxns, etc

 

CELL-MEDIATED IMMUNITY: cells (thymus derived), 75% of circulating lymphocytes                                         

              Immunity which is not transferred with blood

              Effective against tumors, cells with foreign Ag on surface

T Cells: Tc: cytotoxic (killer cells)                                                                                                                               471

                            Td: delayed hypersensitivity, release lymphokines:

                                                             macrophage chemotactic factor

                                                             lymphotoxin

                            Th: helper cells

                            Ts: suppressor cells

 

Recognition of self:          (p 473) Apoptosis: Clonal selection hypothesis: Burnet in 1950s:

              Immune cells generated by random recombination:     portions of DNA deleted, spliced together

              Each cell makes only a single antibody, unique to that cell, coats itself with it

              Encounter with an antigen which reacts with that cell leads to destruction of cell, creating tolerance

              Titer

MAJOR HISTOCOMOPATIBILITY COMPLEX: (p 474) glycoproteins identify self.

 

MECHANISM OF IMMUNE RESPONSE:

              Clonal selection, memory and plasma cells                                                                                            477, 493

                            anamnestic (upward memory response)

ACQUIRED IMMUNITY: natural through exposure, artificial, vaccines

 

HYPERSENSITIVITY: Four types, I, II, III, IV.                                                                                                       508

I             Anaphylaxis: within minutes, either systemic or localized

                            IgE Ab are cytotrophic

 

delayed hypersensitivity (IV)              12-24 hours later, tuberculin, PI, hapten binds to cells, T cells and macrophages move in, trigger inflammation