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28 Cards in this Set
- Front
- Back
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Which cells recognize extracellular components? Intracellular?
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Extra = B cells
Intra = T cells recall: B cells can recognize less specific glycoprotein or polysaccharide antigens, which T cells (high maintenance) can only recognize peptides that are presented to them by MHC. |
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* What are the effector function of B cells?
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1. Neutralization of microbe
2. Opsonization & Phagocytosis 3. Complement Activation |
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* What are the effector function of Helper T cells?
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all via cytokines
1. Activation of Macrophages 2. Inflammation 3. Proliferation and Differentiation of B and T lymphocytes |
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* What are the effector function of Cytolytic T cells?
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Direct killing of infected cells
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what are epitopes?
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antigenic determinants --> actual molecular structure that is recognized by an Ab or antigen-specific membrane receptor on lymphocytes
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Do B or T cell have ARM (antigen receptor molecules) on their surface for 3D conformations of Ags?
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B (any # of molecules)
T cells recognize peptides presented in MHC |
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Which type of lymphocyte recognizes linear peptides?
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T cells (produced by processing of antigen and bound to MHC)
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Do B or T cells recognizes soluble antigens?
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B cells
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What are the three type of APCs? which is the most potent activator of naive T cells?
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1. DC (most potent activator)
2. Macrophages 3. B cells |
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How are MHC genes expressed?
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Codominantly (both parental chromosomes is expressed)
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What cells to MHC-I present to? MHC-II?
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MHC-1 --> CD8
MHC-2 --> CD4 * present to naive T cells |
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Could different individuals have the same MHC genes and molecules?
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No. (only identical twins)
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What types of molecules can MHCs bind?
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ONLY PEPTIDES
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How does the binding groove differ for MHC-1 and MHC-2?
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MHC-1 is "closed" at both ends
MHC-2 is "open" at both ends |
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Which domain in the MHC-I bind the T cell co-receptor CD8?
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alpha-3
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Which domain in the MHC-II bind the T cell co-receptor CD4?
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beta-2
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Is there recombination mechanisms in MHC molecules that contribute to their diversity?
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No. all polymorphism is determined in the germline
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Do MHC-I or MHC-II bind larger peptides?
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MHC-II binds larger (10-30)
MHC-I binds peptides of 8-11 units |
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What is HLA?
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Human Leukocyte Antigen
loci of MHC genes |
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Are MHC-II dimers composed of proteins derived from both maternal/paternal chromosomes?
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Remember: MHC alleles are co-dominant
MHC-II dimers can be derived from one or both chromosomes |
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Which Inflammatory cytokines activate DCs?
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TNF-a and IL-1
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Can a DC present antigen to more than one T cell in the secondary lymphoid tissues?
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Yes.
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Endogenous antigen, which MHC? Exogenous antigen?
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Endogenous = MHC1
Exogenous = MHC2 |
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How do peptides get across ER in the MHC-1 presentation pathway? What occurs there?
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TAP 1 & 2 (transporter of antigen proteins)
synthesis and assembly of a-chain and b-2M (of MHC-1) |
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What is the role of HLA-DM in the processing of MHC-2 presentation?
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removes CLIP protein in exchange for antigenic peptide
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What three cells express MHC2?
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APCs: DCs, macrophages, B cells
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What is meant by the necessary co-stimulation of T cells? what are the co-stimulator molecules that interact between MHCs and T cells?
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in addition to binding the MHC-peptide, T cells require binding of a "second signal"
on the MHC --> B7=CD28 <-- on the T cell |
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What are the co-stimulators (or 2nd receptors) of T and B cells?
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T cells: B7=CD28
B cells: CR2 |
