Activation of Adaptive Immunity Flashcards
2 types of pro-APCs that use class II MHC?
Dendritic cells, macrophages, b cells
What do DCs present to?
naive T cells
What do macrophages present to?
activated (effector) T cells
What do B cells present to?
activated (effector) T cells
Non-professional APCs are what kinds of cells?
all other nucleated cells; use MHC I
How many MHC genes does each individual have?
6
HLA genes are highly polymorphic and have what kind of expression?
codominant
MHC molecules have what 3 domains?
peptide-binding, constant domain, and transmembrane domain
What superfamily do MHC molecules belong to?
immunoglobulin
Peptides that are presented within MHC I are approximately how many AAs long?
8-11
What are the 3 major MHC I genes?
HLA-A, B, and C
What kind of interaction do protein Ags have with MHC class I?
non-covalent
What is the main purpose for MHC class I?
to present endogenously processed peptides for CD8 T CELLS
Each MHC class I HLA binds to what other molecule?
beta-2 microglobulin
“Endogenous” can also include what?
proteins encoded by viruses and intracellular pathogens
what proteins help to transport proteins into the ER for transfer to MHC I?
TAP1/2
Class II MHC present antigens to which cells?
CD4 helper T cells
Peptides presented on Class II MHC are how many amino acids long?
13-25
The processed peptide interacts with what two domains of the MHC Class II?
alpha 1 and beta 1
Extracellular antigens are taken up by professional APCs through what 3 processes?
phagocytosis, receptor-mediated endocytosis, pinocytosis
What two chains make up MHC II?
alpha and beta
Where is MHC II loaded with antigens?
endosomes
Where does the invariant chain sit?
in the grove of MHC II while in ER; prevents from binding to own proteins
How is the invariant chain removed?
protein CLIP removed by HLA-DM
CD8 binds to what domain of MHC class I?
Alpha 3
CD4 binds to what domain of MHC class II?
Beta 2
What process is defined as “Ags taken up from outside can be presented by class I MHC”?
cross-presentation
What cells have a specialized capacity to process exogenous antigens into the MHC I pathway?
Professional APCs
What does cross-presentation help to provide the immune system with?
generating immunity to intracellular pathogens like viruses
How do APCs solve the dilemma of an ingested virus-infected cell?
In order for viral proteins to be presented APCs “leak” exogenous Ags into cytoplasm where they are processed and cross-presented within MHC I
What are the 2 surface Igs for BCR?
IgM and IgD
What are the two main Igs associated with BCR?
Igalpha and Ig-beta
BCRs can recognize which kind of Ags?
lipids, crabs, proteins, DNA
What is the ID marker for all T cells?
CD3
Most TCRs are composed of which 2 chains?
alpha and beta
gamma/delta T cells are a major T cell population in what tissue?
epithelial
gamma/delta T cells are directly activated by?
PAMPs
gamma/delta T cells are believed to have a prominent role in?
recognition of lipid antigens
Professional APCs are special cells can express?
high level of both MHC and co-stimulatory molecules
An activated B cell is transformed into?
plasma cell that secrete Abs
Where are plasma cells found?
lymphoid organs
