A vaccine is clearly needed to stem the spread of HIV. Within the past 18 months, 3 large efficacy trials of candidate HIV vaccines have been suspended or canceled due to efficacy and safety concerns. Basic immunology and immunogen design are therefore driving the development of the next generation of HIV vaccines. This presentation will highlight advances made in the last 12 months in defining potentially protective immune responses to HIV, and determining how to stimulate them through vaccination.  Information will derive from 4 approaches:  studies of individuals whose sera neutralize a broad range of HIV isolates to inform which areas of the envelope glycoprotein are targeted by these broadly-neutralizing antibodies; structural biology of neutralizing antibody interactions with different envelope antigens to inform how to better design immunogens to stimulate broadly neutralizing antibodies; studies of long-term non-progressors to determine what cellular immune responses or other factors may control viral replication; and studies of vaccine tests in non-human primates, which provide insight into how different immune responses may have different influences upon HIV or SIV infection. Throughout the presentation, information will be provided on where and when the latest information will be presented at CROI.