Human immunodeficiency virus type 1 MN envelope glycoprotein gp120 V3 loop (HIV-1 MN gp120 V3 loop) (HIV-1 MN gp120 V3 loop)

The Human immunodeficiency virus type 1 (HIV-1) MN envelope glycoprotein gp120 V3 loop is a specific domain of the viral envelope protein from the MN strain, a lab-adapted HIV-1 isolate. This loop, typically consisting of 35 amino acids, is a critical component of the viral entry machinery, serving as the primary site for binding to host cell co-receptors such as CCR5 or CXCR4 (Zolla-Pazner, 2004). Historically designated as the principal neutralizing determinant (PND), the V3 loop is highly immunogenic and was the primary target for early vaccine candidates like AIDSVAX B/B and AIDSVAX B/E (Goudsmit et al., 1988; Flynn et al., 2005). Vaccine-elicited antibodies against the MN V3 loop aim to neutralize the virus by sterically blocking its ability to engage co-receptors, thereby preventing membrane fusion and infection. However, the V3 loop is characterized by significant sequence variability and conformational masking in primary HIV-1 isolates, which often allows the virus to escape neutralization by antibodies elicited against a single strain like MN (Haynes et al., 2012). Despite these challenges, the V3 loop remains a focal point in HIV research for developing antibodies that can target conserved structural elements within the loop to achieve broader protection.

Other names

HIV-1 MN V3 loopPrincipal neutralizing determinant (PND) of HIV-1 MNgp120 third variable loop (MN strain)MN-V3

Neutralization of viral entry by sterically hindering the interaction between the gp120 V3 loop and host cell co-receptors (CCR5 or CXCR4) (Zolla-Pazner, 2004).