Immunology: HIV and Immune Disorders

CXCR4 is a chemokine receptor, which HIV utilizes as a coreceptor for entry into naive CD4+ T-cells and mature dendritic cells. Another chemokine receptor, CCR5 is used particularly for entry of HIV into immature dendritic cells, macrophages and activated effector or memory CD4+ T-cells.

The HIV envelope protein gp120 binds to CD4. This targets the virus to this T-cell subset.

gp120 is an envelope protein,  which binds to CD4 on the T-cell. Antibodies to the V3 loop of gp120 arise during the disease and are particularly effective as neutralising agents in vitro, although less so in vivo. Generally, neutralising antibodies are more effective against HIV-2 than against HIV-1.

CD8 numbers are largely unaffected. It is the ratio of CD4:CD8 that falls dramatically.

Sodium cromoglycate is a mast cell stabiliser,  which makes the cell resistant to triggering. It is thus able to block type I hypersensitivity.