Chapter 3- Antigen Capture and Presentation to Lymphocytes Flashcards
what are the antigen presenting cells and what is each of their response
- dendritic cell: naive T cell activation, clonal expansion and differentiation into effector T cells
- Macrophage: effector T cell activation: activation of macrophages (cell mediated immunity)
- B cell: effector T cell activation: B cell activation and antibody production (humoral immunity)
what is the function of cytotoxic T cells and what MHC class do they recognize
killing of infected cells, recognize CD8+ cells
what is the role of dendritic cells in antigen capture and presentation in lymph node and blood
- lymph node collects antigen from tissue
- blood borne antigens are captured by antigen presenting cells in the spleen
what are costimulators important for
antigen presentation to dendritic cells to activate naive T cells
CD8T cells can only respond to antigen presented by _____
MHC Class I molecules
CD4T cells can only respond to antigen presented by _____
MHC Class II molecules
describe the structure of the Class I MHC molecule- polymorphic regions, peptide length and what binds co-receptor
- polymorphic regions: alpha1 and alpha2
- peptide binding cleft for peptides 8-9 amino acids long
- alpha3 binds CD8T cell co- receptor
describe the structure of the class II MHC molecule- polymorphic regions, peptide length and what binds co-receptor
- polymorphic regions: alpha1 and beta1
- peptide binding cleft for peptides 10-30 amino acids long
- alpha2 and beta2 binds CD4 T cell co receptor
what genes are the most polymorphic genes in the genome
Class I and II MHC
the total number of HLA alleles in the human population is about _____ class I alleles and ____ class II alleles
10,000; 3,000
codominant expression of alleles inherited from ___
parents
what are polymorphic genes
many different alleles are present in the population
what is the significance of polymorphic genes
different individuals are able to present and respond to different microbial peptides
what is codominant expression
both parental alleles of each MHC gene are expressed
what is the significance of codominant expression
increases number of different MHC molecules that can present peptides to T cells
what are the MHC expressing cell types
-Class II: dendritic cells, macrophages, B cells
- Class I: all nucleated cells
what is the significant of the Class II MHC expressing cell types
CD4+ helper T lymphocytes interact with dendritic cells, macrophages, and B lymphocytes
what is the significance of the Class I MHC expressing cell types
- CD8+ CTLs can kill any type of virus infected cell
what do CD8+ Cytotoxic T cells recognize
endogenous antigen presented by MHC class I molecules on an infected cell
what do CD4+ Helper T cells recognize
exogenous antigen presented by MHC Class II molecules on a professional APC
what is the Class I MHC pathway of processing cytosolic antigens
-production of proteins in the cytosol
- proteolytic degradation of proteins
- transport of peptides form cytosol to ER
- assembly of peptide class I complexes in ER
- surface expression of peptide class I complexes
what is the class II MHC pathway of processing internalized vesicular antigens
-uptake of extracellular proteins into vesicular compartments of APC
- processing of internalized proteins in endosomal/lysosomal vesicles
- association of processed peptides with class II MHC molecules in vesicles
- expression of peptide MHC complexes on cell surface
what are O antigens
polysaccharides
what can antibodies recognize
lipids, nucleic acids, and other types of molecules
