Use the Following Information When Answering the Corresponding Questions)

Use the following information when answering the corresponding questions) .
It has been shown that there are two distinct variants of the HIV virus Bleul et al. 1997. The HIV coreceptors CXCR4 and CCR differentially regulated on human T- lymphocytes. Proceedings of the National Academy of Science 94:1925- 30) . One virus preferentially infects macrophages and is called M- tropic. The other preferentially infects T cells and is called T- tropic. The M- tropic viruses use CCR5 and CD4 as coreceptors, and the T- tropic viruses use CXCR4 and CD4 as coreceptors. The
M- tropic viruses are found early in HIV infections; the T- tropic viruses are found late in infections, when AIDS symptoms are prevalent. T- tropic viruses are associated with a drastic decrease in T cells. Macrophages go to the site of wounds, where they are used to fight infections. T cells circulate in the body and fight infections at many sites.
-Which receptors for HIV would you expect to find on macrophages and T cells?

A) CXCR4 and CD4 on macrophages; CCR5 and CD4 on T cells
B) CD4 and CXCR4 on macrophages; CXCR4 and CD4 on T cells
C) CCR5 and CD4 on macrophages; CXCR4 and CD4 on T cells
D) CCR5 and CXCR4 on macrophages; CD4 and CXCR4 on T cells