Term
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Definition
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Term
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Definition
| Major Histocompatibility Complex AKA Human Leukocyte Antigen |
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Term
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Definition
| MHC I: three alpha segments, + B2 microglobulin. MHC II: two alpha segments, two beta segments. |
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Term
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Definition
| MHC I: on almost all cells. MHC II: on immune cells only |
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Term
| MHC I and II number of types |
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Definition
| MHC I: 6 types, MHC II: 8 types |
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Term
| MHC I: types A, B, C function |
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Definition
| Present antigen to cytotoxic CD8 T cells |
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Term
| MHC I: types E, G function |
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Definition
| Ligand for natural killer cells |
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Definition
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Term
| MHC II: types DP, DQ, DR function |
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Definition
| Present antigen to helper CD4 T cells |
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Term
| MHC II: types DM, DO function |
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Definition
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Term
| Antigens presented by MHC I |
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Definition
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Term
| Antigens presented by MHC II |
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Definition
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Term
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Definition
| Intracellular Ag is processed by proteosome; goes to ER where it binds to MHC I. Bound MHC1 is exported to surface of cell |
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Term
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Definition
| In MHC I presentation, stabilizes Class 1 heavy chain until B2 microglobulin binds |
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Term
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Definition
| In MHC I Presentation, this forms after Calnexin is released. Contains Tapasin, TAP, ERp57, PDI; |
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Term
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Definition
| Delivers peptide, forms mature MHC I molecule |
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Term
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Definition
| Extracellular Ag is internalized and a phagolysosome converts it to smaller peptides. A vesicle containing unbound MHC II fuses with the phagolysosome, allowing the peptide to bind MHC II, and the vesicle continues until it fuses with surface |
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Term
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Definition
| Prevents peptide binding while MHC 2 is in the ER, before it goes into the vesicle |
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Term
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Definition
| Invariant chain is cleaved once MHC2 is in a vesicle, but CLIP fragment still blocks peptide access |
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Term
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Definition
| Required to remove CLIP fragment and allow peptide binding in MHC2 recognition |
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Term
| Binding grooves in MHC I and II, implications on what peptides may bind |
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Definition
| MHC I: length of binding groove favors binding of a 9-mer. MHC II: shorter binding groove allows for more flexibility with binding peptide length |
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Term
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Definition
| T cells enter lymph nodes through high endothelial venules, and proceed to "shake hands" with all peptide+MHC combinations present |
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Term
| Factors that guide T cells to make interactions with peptide+MHC |
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Definition
| Selectin, chemoattractant, and an Ig family member |
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Term
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Definition
| Interaction that takes place between the proper MHC, peptide, and T-cell receptor |
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Term
| Factors that assist the immunological synapse (5) |
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Definition
| CD28 on T cell interacts with B7 on dendritic cell; CD4 or CD8 required to confirm specificity, integrins/ICAMs stablize |
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Term
| Supramolecular Activation Complex |
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Definition
| collection of factors contributing to immunological synapse |
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Term
| Transcription factors activated by signaling cascade induced by immunological synapse |
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Definition
| NFKB, NFAT, AP-1. NFKB and NFAT induce production of autocrine/paracrine IL-2, and all of the above contribute to cell proliferation and differentiation |
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Term
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Definition
| Drugs that target IL-2 for immune suppression in organ transplants. Cyclosporin A inhibits IL-2 transcription; Rapamycin inhibits IL-2R signaling |
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Term
| Transplant rejection stages (3) |
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Definition
| Hyperacute (anti-blood group Ag, local inflammation), Acute (CD8 T cells), Chronic (CD4 T cells, B cells) |
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Term
| Direct/indirect allorecognition |
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Definition
| T cells have varying affinity for MHC/peptide. Direct - days to weeks before response. Indirect - weeks-years |
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Term
| Autograft, allograft, xenograft |
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Definition
| Same person, same species, different species |
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Term
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Definition
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Term
| MHC-linked autoimmune diseases, examples (5) |
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Definition
| Systemic lupus, Type 1 diabetes, myasthenia gravis, rheumatoid arthritis, celiac disease |
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Term
| Viruses/bacteria that modulate MHC, examples (2) |
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Definition
| Cytomegalovirus produces MHC1 homolog; mycobacterium inhibit MHC2 presentation |
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Term
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Definition
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Term
| Overview: Two types of T cell lineages based on TCR type |
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Definition
| T cells expressing alpha:beta receptors, T cells expressing gamma:delta receptors |
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Term
| Alpha:beta receptor-expressing cells go through positive and negative selection |
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Definition
| + selection = must be able to recognize self MHC; - selection = it can't be too strong. Allows for recognition of foreign antigen presented by self-MHC |
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Term
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Definition
| Bone marrow --> thymus for development --> secondary lymph tissues |
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Term
| T-cell receptor rearrangement: Progenitor expresses |
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Definition
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Term
| T-cell receptor rearrangement: Factor that commits progenitor for T cell lineage |
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Definition
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Term
| T-cell receptor rearrangement: Changes that occur when progenitor commits |
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Definition
| Loses CD34, begins expressing CD2, CD5, CD127 (<-- IL-7 receptor) |
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Term
| T-cell receptor rearrangement: Possible fates of Beta, gamma, delta rearrangement |
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Definition
| If B chain rearranges first: Double positive pre-TCR. If gamma/delta receptor is made before B chain: Gamma delta cell produced |
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Term
| T-cell receptor rearrangement: B chain rearrangement, Pre-TCR details |
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Definition
| B chain has V, D, J regions similar to Ig heavy chain. D-J first, followed by V-DJ. After rearrangement, pTalpha is a surrogate alpha chain that stops further B chain rearrangement. |
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Term
| T-cell receptor rearrangement: How many chances to get B chain rearrangment right? |
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Definition
| Four - two separate sets of D, J, and C segments on each allele. 80% success rate |
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Term
| T-cell receptor rearrangement: Possible fates of Alpha, gamma, delta rearrangement |
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Definition
| If A chain rearranges first: ++ A:B cell. If gamma/delta receptor made first: Gamma/delta cell produced |
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Term
| T-cell receptor rearrangement: Alpha chain rearrangement |
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Definition
| A chain has V, J regions similar to Ig light chain. This will not start unless B chain is already expressed. Successful rearrangement does NOT stop the second A chain allele from rearranging, this would lead to 2 different TCRs expressed on the same cell |
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Term
| T-cell receptor rearrangement: Stages where Notch is expressed |
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Definition
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Term
| T-cell receptor rearrangement: Stages where RAG1/2 is expressed |
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Definition
| During B,g,d and A,g,d rearrangements only |
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Term
| T-cell receptor rearrangement: Stages where TdT is expressed |
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Definition
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Term
| Positive selection: overview |
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Definition
| TCR must be able to recognize self-MHC |
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Term
| Positive selection: where it occurs, which cells present MHC |
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Definition
| Thymic cortex; cortical epithelial cells present MHC |
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Term
| Positive selection: if MHC I is recognized? If MHC II? |
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Definition
| MHC I --> retains CD8 and gets rid of CD4. MHC II --> retains CD4 |
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Term
| Positive selection: time course before a cell dies? |
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Definition
| TCR has 3-4 days to recognize an MHC. If it fails, it has 3-4 days to do more alpha chain rearrangment to try recognizing an MHC. If this still fails, cell dies. A-chain rearrangement stops after + selection is complete |
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Term
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Definition
| Deficiency in MHC I --> CD8 T cells do not get produced. Deficiency in MHC II --> CD4 T cells do not get produced. |
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Term
| Negative selection: overview |
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Definition
| Cell must not recognize self-MHC:self-peptide complexes too strongly, or else it is too auto-reactive and is eliminated |
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Term
| Negative selection: which cells present MHC:peptide? |
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Definition
| Dendritic cells or macrophages in thymus |
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Term
| Negative selection: Autoimmune Regulator (AIRE) |
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Definition
| Transcribes lots of tissue-specific genes, so that TCRs have practice ignoring self-signals from many different tissue types before they can pass negative selection |
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Term
| CD4 Regulatory T cells express factors (2) |
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Definition
| CD25 = the IL-2 receptor alpha chain; FoxP3 = critical regulatory factor |
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Term
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Definition
| Mutation of FoxP3, which is on X chromosome (Happens in boys) |
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Term
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Definition
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Term
| Types of effector T cells (3) |
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Definition
| Th (helper), Tc (cytotoxic), Treg (regulatory) |
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Term
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Definition
| Cell-mediated; helps macrophage kill pathogens |
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Term
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Definition
| Humoral mediated; helps B cell make antibodies |
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Term
| TH1 helper T cells are activated by which cytokine? |
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Definition
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Term
| TH1 helper T cells produce which cytokines? (5) |
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Definition
| TNF-a, INF-g, IL-2, CXCL2, IL-3 |
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Term
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Definition
| Changes vascular endothlium, allowing macrophages to adhere to blood vessel walls and leave |
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Term
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Definition
| Activates macrophage; can induce phagolysosome fusion that is inhibited by Mycobacterium tuberculosis; can induce killing of other pathogens within the phagosomes |
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Term
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Definition
| Enhances T cell proliferation |
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Term
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Definition
| Macrophage chemoattractant |
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Term
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Definition
| assist macrophage differentiation in bone marrow |
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Term
| TH2 helper T cells are activated by which cytokines? (3) |
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Definition
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Term
| TH2 helper T cells produce which cytokines? (4) |
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Definition
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Term
| Naturak Killer Cells are activated by which cytokines (3) |
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Definition
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Term
| Positive feedback between natural killer cells and macrophages |
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Definition
| NK cells release IFNg --> stimulates macrophages --> macrophages produce IL-12 --> activates NK cells |
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