Funding: This work was supported by the European Commission sixth Frame Work Programme as part of the European Vaccines and Microbicides Enterprise (EUROPRISE), the European Commission seventh Frame Work Programme as part of the Combined Highly Active Anti-retroviral Microbicides
project (CHAARM)[to RAW], the Bill and Melinda Gates Foundation as part of the Collaboration for AIDS Vaccine Discovery (CAVD
grant 38637 [to RAW] and
grant 1032144 [to
MSS]-RRB-, and the UK Medical Research Council [RAW and AF].