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med immunology 9
biology of the T lymphocite
| Question | Answer |
|---|---|
| Each TCR has 2 chains called ______ and ______. | alpha, beta |
| 2 chains of TCR are linked by ___________. | disulfide bond. |
| alpha and beta chains of TCR are transmembrane(integral)____________. | glycoproteins |
| Each chain of TCR has a ______region and a ______ region, similar to Ig molecule | variable, constant |
| Each variable region of TCR has 3 ____________. | hypervariable regions |
| What is the other name for hypervariable regions of TCR? | complementarity determining regions (CDR) |
| What are specific names of 3 complementarity determining regions of TCR? | CDR1, CDR2, CDR3 |
| Which CDR of TCR CDRs is the most hypervariable? | CDR3 |
| Why TCR structure is similar to BCR in many ways? | Because both evolved from a common ancestral Ig gene superfamily |
| Which receptor, BCR or TCR, has flexible hinges that allow it to conform to different shapes and sizes of antigen? | BCR |
| Which receptor, BCR or TCR,is rigid and not flexible? | TCR |
| Which receptor, BCR or TCR, can bind complex soluble antigen and hydrophobic protein antigen? | BCR |
| Which receptor, BCR or TCR, only binds small simple peptides expressed on the MHC of cells? | TCR |
| Which receptor, BCR or TCR, exists as either attached to the cell or secreted as antibody? | BCR |
| Which receptor, BCR or TCR, mainly attached to the cell surface and is not secreted? | TCR |
| Which receptor, BCR or TCR, undergo somatic hypermutation or isotype switching in response to different antigen types? | BCR |
| Which receptor, BCR or TCR, do not change when responding to antigen? | TCR |
| What substances make it easier and lower the threshold for the T cell to bind antigen? | Coreceptors |
| List 2 examples of coreceptors | CD4, CD8 |
| What is the normal ratio of CD4+T-cell to CD8+T-cell in lymphatic circulation? | 2:1 |
| Why HIV patient's CD4+T-cell to CD8+T-cell ratio is reduced? | Because HIV attack CD4+(helper T-cells) for CD4's affinitiy to bind with HIV. |
| Why HIV has the potential to disable both second and third lines of defense? | Because macrophages and dendritic cells also express CD4 at low levels and may be affected and destroyed by HIV. |
| What is called that secondary signals which is needed for naive T-cell to be fully activated? | costimulatory interaction signals (secondary signal) |
| List 2 of examples of costimulator. | CD28, B7 |
| Where CD28 is expressed? | on mature T-cell |
| Where B7 is located? | APC |
| After the interaction of CD28 and B7 occurs, T cells becomes _________, and it leads _________ which is necessary for the production of other subtypes of T cells involved in CMI(cell mediated immunity). | fully activated, cytokine interleukin 2 |
| How many distinct sets of genes for TCR and what are they? | 4, alpha, beta, gamma, delta |
| What regions do TCRs have? | variable and constant |
| How many genes are for V alpha TCR? | 70 |
| How many genes are for V beta TCR? | 50 |
| which genes are more and fewer for V TCR genes? | more alpha and beta, fewer gamma and delta (5-10) |
| Potentially how many different TCRs can be produced? | 10 trilliton (10^15) |
| Why in reality the population of TCRs found in each individual is much smaller than potential number? | Because thymic selection eliminates self reactive T cells in thymus during T cell differentiation. |
| THe process of thymic selection which eliminates ___________ in _______ during ___________. | self reactive T cells, thymus, T cell differentiation |
| Thymic selection selects TCRs that are _______. | suitable |
| Suitable properties of TCRs are: it must be able to effectively bind _________, and it must not attack ___________ that could lead to __________. | MHC class I or II, self antigens, autoimmunity |
| in the process of thymic selection, T cells that have ________ to the MHC of thymus epithelial cells are favored and selected, and T cells with ________ or ________ are deleted by apoptosis. | intermediate affinity, poor affinity, excessive affinity |
| What does double negative T cell mean? | naive/undifferentiated T cell. |
| What does double positive T cell mean? | T cell that has the potential to becoming either CD4+ or CD8+ |
| What does single positive T cell mean? | Mature and differentiated CD4+ or CD8+ T cell |
| Negative selection is the phenomenon that a gene called _____________ eliminates the production of _________. | autoimmune regulator (AIRE), self reacting T cells. |
| What is called a process which a gene which eliminates the production of self reacting T cells? | Negative selection |
| What disease is caused by a genetic mutaion in the AIRE gene? | DiGerge syndrome which thymus is underdeveloped or inactive, or polyendocrinoppathy-candidiasis ectodermal dystrophy which destroys multiple glands |
| What is AIRE? | a gene which produces a protein that controls and eliminates the production of self reacting T cells. |
| Which receptor, BCR or TCR,a bivalent and it has 2 Ag binding site. | BCR |
| Which receptor, BCR or TCR, monovalent with 1 Ag binding site. | TCR |
Created by:
hiroko lucky2
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