DrVirgo
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A 56 year old homo man is hospitalized for PCP. His CD 4 count is 30.
Western blot is positive for antibodies to gp41 and gp120, but negative for antibodies to p24, p17, and p7p9. Why do antibodies to envelope antigens ocntinue to be produced until the death of the patient, while antibodies to internal structural proteins disappear?
A. Envelope glycoproteins of the virus are heavily glycosylated
B. IgM antibodies can be made in the absence of T cell help
C. Once the population of susceptible cells falls to a certain level, viral structural proteins are no longer produced
D. The virus is parasitic in the chromosomes and hidden from the immune response
E. The virus overproduces envelope antigens.
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| DrVirgo
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Any guesses?
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| DrVirgo
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Answer B. 
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| study_ing
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hmm interesting..that was a good one
so the intracellular ags definitely require T cells, hence no Abs to them
envelope proteins wud be still able to stimulate B cells directly but isotype switching wud not occur
duz that sound right?
good one ..thx again
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| DrVirgo
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This is what happens:
In full blown AIDS, the patient can't make IgG, A, and E because decrease amount of T-Cells.
So NO IgG against the structural proteins... the patient will be negative by ELISA (which tests for IgG against p24 capsid protein)
As for IgM, its production IS POSSIBLE W/O T-Cell help, and continues being produced against glycoproteins gp120 and gp41 (which are constantly being altered by random mutations, genetic drift, etc...
Paradoxically there will be an INCREASE in Ig levels because B Cells will make TOO MUCH IgM in absence of T-Cells!
---Hard question!
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