Immunology question

[Bodom]

Given that emitine blocks viral protein synthesis, which population of T cells would be more affected by it and why: CD8-positive T cells or CD4-positive T cells? Influenza hemagglutinin is used in vaccines. Which is more likely to respond to it -- CD4- or CD8-positive cells? Why? -Thanks

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[VanBrown]

weird and difficult questions.. neither will relate to the mcat.

however.. if I had to guess I would say that CD8 cells would be more effected because they need a lot of perforin and granzyme to achieve CTL attack. Also, viral infections ellicit CD8 responses more heavily than CD4.

also, HA is used in vaccines which are meant to elicit CD4 responses and Ab maturation and memory cell development. So, without knowing anything really about the mechanism, the answer should be CD4+. As to why? Well anything in circulation will act as an antigen which will (should be) recognized by naive B-cells and be taken up by macrophages etc in lymphoid tissues and presented to Cd4+ cells. HA may be used because it displays a pathogen associated molecular pattern that can elicit a T-independent response.. I don't know I haven't seen the moecular structure of HA.


If those types of questions do come up on the MCAT you need to focus on the information given and what you know about how that information will elicit an immune response. Viral proteins = viral infection = humoral (CD8+) response. Immunization = want to make Abs and memory cells = B-cells needed = CD4+ cells involved.

 

[neil100]

weird and difficult questions.. neither will relate to the mcat.

however.. if I had to guess I would say that CD8 cells would be more effected because they need a lot of perforin and granzyme to achieve CTL attack. Also, viral infections ellicit CD8 responses more heavily than CD4.

also, HA is used in vaccines which are meant to elicit CD4 responses and Ab maturation and memory cell development. So, without knowing anything really about the mechanism, the answer should be CD4+. As to why? Well anything in circulation will act as an antigen which will (should be) recognized by naive B-cells and be taken up by macrophages etc in lymphoid tissues and presented to Cd4+ cells. HA may be used because it displays a pathogen associated molecular pattern that can elicit a T-independent response.. I don't know I haven't seen the moecular structure of HA.


If those types of questions do come up on the MCAT you need to focus on the information given and what you know about how that information will elicit an immune response. Viral proteins = viral infection = humoral (CD8+) response. Immunization = want to make Abs and memory cells = B-cells needed = CD4+ cells involved.

I agree.
CD8+ for virus killing by the mechanism explained above. CD4+ don't do any killing.

CD4+ is meant to be reved'up in vaccines for starting up either humoral process or cytotoxic process for an ag. and then create memory cells of course.


But this is way other the top for the MCAT like Van Brown said!