Which marker is found on helper T cells and is a target for HIV?

Which marker is found on helper T cells and is a target for HIV?

• A. CD4
• B. CD8
• C. CD3
• D. CD19

Answer: (A)

HIV gains entry by binding to a receptor on the surface of helper T cells. This receptor is CD4, a glycoprotein highly expressed on CD4+ T cells. When HIV’s gp120 binds CD4, it then uses a co-receptor (CCR5 or CXCR4) to fuse with the cell and enter. That makes CD4 the marker found on helper T cells and the one targeted by HIV. Other markers map to different cell types: CD8 is on cytotoxic T cells, CD3 is part of the T cell receptor complex present on many mature T cells, and CD19 is a marker for B cells.

HIV gains entry by binding to a receptor on the surface of helper T cells. This receptor is CD4, a glycoprotein highly expressed on CD4+ T cells. When HIV’s gp120 binds CD4, it then uses a co-receptor (CCR5 or CXCR4) to fuse with the cell and enter. That makes CD4 the marker found on helper T cells and the one targeted by HIV.

Other markers map to different cell types: CD8 is on cytotoxic T cells, CD3 is part of the T cell receptor complex present on many mature T cells, and CD19 is a marker for B cells.