Flashcards in Antigens and Antigen Presentation Deck (23):
What is an antigen?
Substance that reacts with the products of a specific immune response (molecule recognized by T or B cells)
What is an immunogen?
Substance that induces a specific immune response
What is an antibody?
A specific protein produced in response to an immunogen and reacts with an antigen
What is an epitope?
Site of an Ag that is bound by lymphocyte receptors or antibody
Also known as antigenic determinant
What is a Bc epitope?
Specific portion of a macromolecular Ag to which an Ab binds
What is a Tc epitope?
The peptide portion that is recognized by a TCR when it is displayed bound to an MHC molecule
Can directly stimulate B cells to produce Ab without T cell help
Cannot directly stimulate Ab production without the help of T cells
How do follicular dendritic cells present antigens?
Display Ags to B-CELLS to initiate humoral immunity
What is the role of dendritic cells in antigen capture and display?
1. DC captures antigen and enters lymphatic vessels
2. Transported to lymph node or spleen
3. Protein antigens displayed for recognition by T-CELLS
How do B cell epitopes differ from T cell epitopes?
Antigen is polypeptide, polysaccharide, or nucleic acid
Linear or conformational
Recognized/bound by BCR
Extracellular or on cell surface
Antigen is a protein
Bound by TCR only after being processed/display by MHC
Intra- or extracellular
How do T-dependent antigens interact with B-cells?
They are processed by APCs, presented via MHC, and bound by TCR
What chromosome contains the HLA genes?
What is MHC?
Complex of genes encoding cell surface protein molecules that are required for antigen presentation to T cells
Which HLA types are preferred for transplantation?
HLA-DR > HLA-B > HLA-A
HLA types encoded by MHC Class II Locus
DR, DQ, DP
HLA types encoded by MHC Class I Locus
B, C, A
What is encoded in MHC Class III Locus?
Which cells contain MHC I?
All nucleated cells
Which cells contain MHC II?
What forms the peptide binding groove in MHC I and II?
I: alpha chain only
II: alpha and B2M chain
How many peptides can MHC molecules display at one time?
One peptide per MHC