MICR 3230 Chapter Notes -Antigen, V(D)J Recombination, Memory T Cell

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greenfly526

22 Nov 2011

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T cell maturation, activation & differentiation (chapter 10) summary progenitor t cells from bone marrow enter thymus and rearrange tcr genes thymocytes rearrange tcr genes to become t cells small percentage rearrange to become t cells. Dn (double negative) cells lack cd4 and cd8 (early thymocytes) During development, double negative thymocytes develop (expression of either. Positive selection: eliminates t cells unable to recognize self mhc mhc. Negative selection: eliminate thymocytes bearing high affinity receptors for self. Mhc molecules (alone or self mhc plus self antigen) self tolerance. T cell activation initiated by interaction of tcr-cd3 complex with a peptide- Activation requires accessory molecules including co-receptors cd4/cd8. Intracellular signal transduction pathways activated by tcr engagement. T cells expressing cd4 recognize mhc-ii and function as th cells. T cells expressing cd8 recognize mhc-i and function as tc cells. Co-stimulatory signal induced by interaction between b7 on apc and cd28 on. Signal 2 th co-stimulatory signal provided by apc.

Related Questions

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

Which of the following statements is TRUE?

The germline organization of Ig and TCR genes is different in a liver cell as in a mature B or T lymphocyte.

Positive selection is a checkpoint during lymphocyte maturation that ensures the survival of functionally useful lymphocytes.

In the Ig heavy chain gene locus there is found a cluster of V genes and a cluster of J genes.

Only the TCR-alpha gene locus contains D gene segments.

Developing T cells that have a high affinity for self-proteins survive the negative selection checkpoint.

ochrewoodchuck973

1.How do some pathogens prevent complement activation or avoid the effects of activated complement?

A. some pathogens hijack the host's regulatory membrane proteins that inactivate C3b, preventing the triggering of the alternative activation pathway AND some pathogens produce C5a peptidase that causes destruction of phagoctyes recruited to the area of infection

B. some pathogens produce C5a peptidase that causes destruction of phagoctyes recruited to the area of infection

C. some pathogens produce C5a peptidase that destroys complement C5a, a chemoattractant that recruits phagocytes to the area of infection

D. Some pathogen hijack the host's regultory membrane proteins that inactivate C3b, preventing the triggering of the alternative activation pathway AND some pathogens produce C5a peptidase that destroys complement C5a, a chemoattractant that recruits phagocytes to the area of infection.

2. One of the most important jobs of dendritic cells is

A. production of complement proteins

B. activation of T cells by breakdown of whole antigens and presentation of antigenic epitopes on MHC molecules

C. stimulation of cytokine production by neutrophils

D. activation of B cells by combining epitopes and presentation of whole antigens on MHC molecules

E. production of IgD

3. Normal Microbiota

A. play no role in affecting pathogen growth

B. are the organisms that typically reside on and in your body

C. enhance infection by pathogens

D. are the organisms that typically reside on and in your body AND protect aganist infection by pathogens

E. protect against infection by pathogens.

4. why is the process of gene rearrangement used in creating antibodies and T-cell receptors (TCRs) so important?

A. the given choices are all reasons that generearrangement is critical in adaptive immunity

B. This is how our systems produce memory of previous exposures, a key trait in adaptive immune responses

C. without it, we would need a single gene for every antibody and TCR required to mount all the possible responses needed during our lives

D. interactions with antigens stimulate cells to initate these processes, building the best and strongest response possible to that antigen

E. this is the same DNA altering process that leads to cancer. Understanding it leads to better treatments for cancer.

MICR 3230 Chapter Notes -Antigen, V(D)J Recombination, Memory T Cell

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