Chasing the Infecting HIV-1

In the absence of an effective prophylactic vaccine and successful viral eradication strategies, the burden of human immunodeficiency virus type 1 (HIV-1) infection and disease continues to grow worldwide. The events characterizing primary HIV-1 infection and the early stages of the infection have been the focus of extensive research addressing the modalities of HIV-1 transmission. A thorough understanding of the early viral and host interactions leading to the establishment of productive infection will provide the necessary evidence base for developing successful prophylactic and therapeutic tools, including drug regimens, vaccines, and microbicides, and for guiding clinical management and the optimal time for the initiation of antiretroviral therapy. From a global perspective, among the various possible modes of acquisition, the majority of new HIV-1 infections occur through sexual transmission across mucosal barriers. Early after infection, HIV-1 strains appear to be genetically homogenous but rapidly diversify into a swarm of related but genetically divergent variants that compose the viral quasispecies. The highest degree of diversification is observed in the envelope glycoprotein 120 (gp120), the target of strong immune responses, including T-cell‐mediated and neutralizing antibodies [ 1 , 2 ]. There is substantial evidence to indicate that the diverse quasispecies