HIV/AIDS: Allied responses

The main function of neutralizing antibodies is to block viral entry into host cells. But, for maximal protection against HIV, such antibodies must call upon other elements of the immune system to help with the job.

More than two decades into the AIDS pandemic, and despite intense research on the human immunodeficiency virus (HIV), we still do not have a vaccine to prevent HIV infection. One possibility is to trigger the components of adaptive (specific) immunity¹ — T cells and B-cell-derived antibodies. These immune mediators can function near mucosal surfaces, which are in contact with the external environment and are therefore sites of viral entry and replication. For complete protection against infection, however, a vaccine probably needs to elicit neutralizing antibodies to block viral entry into host cells. How do neutralizing antibodies against the two HIV species — HIV-2 and the more virulent HIV-1 — function? On page 101 of this issue, Hessell and colleagues² report on the mechanism through which one of the best-known neutralizing antibodies to HIV-1 functions in vivo.