IMM250H1 Lecture : Notes taken during lecture

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redtermite204

19 Dec 2011

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How t cell receptor generated thorugh somatic recombination, vdj recombination and how tcr diversity generated. How t cell develop in bone marrow, then in thymus. How they go thorugh step wise development defined by changes in cell surface expression, cd4, cd8, cd44, cd28. During development, tcr rearranged and how t cells that express fnctional tcr at surface go through steps poisitve and negative selections. What happens to t cells that went through selection escape thymus 2-4% of t cells escape thymus. At periphery, scan hmc peptide complexes at surface of antigen presenting cells if encounter, foreign antigen for whcih enough affinity build up response, proliferate, differentiate. Naive t cells circulate through blood vessels, enter lymphoid tissues by specialized. Gree t cells going through structure of ln, encouter lot of different apcs. Green cells scan peptides at surface of dcs - do not receive sufficient signalling to get activated, eventuallly exit the structure, go back into circultion.

Related Questions

1. Discuss how T-cell receptors differ from immunoglobulins in the way that they recognize antigen. Use the following terms in your answer: peptides, antigen-presenting cells, MHC molecules, and antigen-binding sites.

2. The surrogate light chain operating during pre-B-cell development is made up of VpreB:Î». Its expression with Î¼ on the pre-B-cell surface is an important checkpoint in B-cell maturation. Name the Tcell analog of VpreB:Î»5 and discuss how it is functionally similar

indicate whether you think the statements are true or false, and explain your reasoning. In each of your answers, provide 1-2 specific examples that support your position. (Each of your four answers is worth five points):

A) Memory cells require fewer distinct signals to be activated than naiÌve cells require.

B) Both B cells and T cells undergo âclonal selectionâ after they are activated by antigen.

C) A B cell is only able to present antigen to a T cell that includes the epitope to which the

B cellâs receptor bound.

D) T cells can recognize peptide antigens in the context of MHC I and MHC II regardless of

whether they are Thelper or Tcytotoxic cells.

E) B cells and T cells can both still make productive antigen receptors via V(D)J

recombination even if no P-nucleotides are introduced during the process.

F) Allelic exclusion takes place when a naiÌve T or B cell encounters its specific non-self antigen for the first time and determines whether or not to become activated.

G) B cells have more chances to make a productively rearranged antigen receptor than T cells do.

H) A majority of immature T cells developing in the thymus will survive both positive and negative selection.

I) The reason why T cells are the only type of white blood cell that requires maturation in a specialized organ outside the bone marrow is because they are the only ones that must have antigen processed and presented to them before they can be activated.

violetbear615

Short Answer part 1.

1. What is Notch1, including where it is expressed, and how does the interaction between Notch1 and its ligand mediate T cell development?

2. In what way the thymic conditions is advantageous for the purposes of negative selection?

3. The surrogate light chain operating during pre-B cell development is made up of VpreB:lambda5. Its expression with mu on the pre-B cell surface is an important checkpoint in B cell maturation. Name the T cell analog of VpreB:lambda5 and discuss how it is functionally similar.

4. Mature B cells undergo somatic hypermutation after activation, which, after affinity maturation, results in the production of antibody with a higher affinity for antigen than in the primary antibody response. Suggest some reasons why T cells have not evolved the same capacity.

5. As we age, our thymus shrinks, or atrophies, by a process called involution, yet T cell immunity is still functional in old age. How do T cell numbers in the periphery remain constant in the absence of continual replenishment from the thymus and how does this differ from the maintenance of the B cell repertoire?

IMM250H1 Lecture : Notes taken during lecture

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