adaptive immunity

b cell receptors

b cell receptors

recognize varrious macromolecules

t cell receptors

recognize only peptide fragments of protein antigens

MHC I

antigen presentaion to CD8 t cell

MHC II

antigen presentation to CD4 t cell

fab region

variable region of anibody that interacts with antigen and unique to each antibody

Fc region

intrracts with cell surface receptors and proteins of complement system, common to all antibodies

FC portion of heavy chain

defines class of antibody

epitope

antigenic determinant on an antigen that interacts with different B cell antigen receptors, promote expansion of immune responses

epitope on antigen

what drives diversity in antibody response from the antigen portion

VDJ recombination

what drives diversity in antibody response from the antibody portion

VDJ recombination

random rearrangements of VDJ gene segments resulting in AA sequences in antigen-binding regions of IGs and TCRs which allows for the recognition of antigens from nearly all pathogens

IgM

first antibody class secreted, mainly in blood, pentameric or monomeric, activation of complement and agglutinating pathogens

IgG

monomeric, highest concentration in blood, diffuse into extravascularr sites/ cross placenta, complement activation, nerutralization, opsonizaation, and ADCC

IgD

monomeric, least abundant, on B-cells

IgE

binds to mast cell receptors (histamine release), parasidic response and allergic reactions

IgA

dimeric, passive immunity (breast milk), in mucous secretions, neutralization and agglutinating pathogens

IgG, IgD, IgE

monomeric antibody isotypes

IgA

dimeric isotypes of antibodies

IgM

multimeric isotypes of antibody

IgM

which antibody can have as much as 10 binding sites

IgM and IgG

which antibodies can activate complement

avidity

accumulated strength of multiple affinities

neutralization of pathogeens and toxins, phagocytosis and ADCC, and activation of complement cascade

major function of antibodies

NK cell CD16 Fc receptor recognize cell-bound antibodies and triggers degranulation and apoptosis of target cell

what is anitbody dependent cellular cytotozicity

classical pathway

which pathway of complement is activated by formation of antigen antibody complex

TCR binds small peptides presented on MHC and activate secretion of specific cytokines from APC that drives the differentiation of t cells

How are T-cells activated

helper, regulatory, cytotoxic

three types of T cells

helper T cell

activate cytotoxic t cells and b cells

regulatory t cells

help body distinguish between self and non self, helps prevent autoimmune diseases

cytotoxic t cells

involved in direct killing of pathogens

T cells and MHC do not recognize eachother and produce immune response

barrier to tissue transplantation

graft versus host diseease

string raction to foreign MHC on recipient tissues when a transplant contains donor T cells

superantigen

binding of pathogenic proteins to MHC II outside of peptide binding site

IFNy released, large scale macrophage activation, and cytokine storm

result of superantigen binding MHC II