part of the gp120 envelope protein of HIV-1. The V3 loop is believed to triggers as strong antibody response and is the basis of several candidate anti-HIV vaccines; however, the region is extremely variable among HIV strains. (syn. v3 region)

Section of the gp120 protein on the surface of HIV. Appears to be important in stimulating neutralizing antibodies.

A part of the HIV gp120 surface protein that appears to be important in stimulating neutralizing antibodies.

The third variable loop or V3 loop is a part or region of the Human Immunodeficiency Virus. The V3 loop of the viron's envelope glycoprotein, gp120, allows it to infect human immune cells by binding to a cytokine receptor on the target human immune cell, such as a CCR5 cell or CXCR4 cell, depending on the strain of HIV.