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Background More insight is needed regarding risk factors for prevalent and incident HIV-1 infection among male farm workers in Sub-Saharan Africa to control the HIV-1 epidemic. Methods Male farm workers were recruited from a sugar estate in Zambia to participate in a prospective cohort study. Questionnaire data were collected via interview, and testing was conducted for HIV-1, herpes simplex virus type 2 (HSV-2), and syphilis infection at baseline and follow-up between May 2006 and September 2007. Results Among 1062 workers enrolled, HIV-1 prevalence at baseline was 20.7%. Testing HSV-2 seropositive (adjusted odds ratio (AOR) 5.4, 95% CI 3.6 to 8.1), self-reported genital ulcers in the past year (AOR 2.8, 95% CI 1.9 to 4.2), and being widowed (AOR 3.7, 95% CI 2.0 to 6.9) were significantly associated with prevalent HIV-1 infection. The HIV-1 incidence among 731 initially negative participants with at least one follow-up visit was 4.1 per 1000 person-months (95% CI 2.6 to 5.7); seroconversion was independently associated with prevalent HSV-2 infection (adjusted hazard ratio (AHR) 2.4, 95% CI 1.0 to 5.8) and incident HSV-2 infection (AHR 18.0, 95% CI 4.2 to 76.3). HIV-1 prevalence and incidence rates were similar among migrant and non-migrant workers. Conclusions HIV-1 prevalence and incidence were high, and HSV-2 infection was a risk factor for HIV-1 acquisition. There is an urgent need to expand HIV-1 prevention programmes tailored to farm workers and their communities. [ABSTRACT FROM AUTHOR]

Abstract: Functional human immunodeficiency virus type 1 (HIV-1) env genes have been widely used for vaccine design, neutralization assays, and pathogenesis studies. However, obtaining bona fide functional env clones is a time consuming and labor intensive process. A new high throughput method has been developed to characterize HIV-1 env genes. Multiple rev/env gene cassettes were obtained from each of seven HIV-1 strains using single genome amplification (SGA) PCR. The cytomegalovirus (CMV) promoter was amplified separately by PCR. A promoter PCR (pPCR) method was developed to link both PCR products using an overlapping PCR method. Pseudovirions were generated by cotransfection of pPCR products and pSG3Δenv backbone into 293T cells. After infecting TZM-bl cells, 75 out of 87 (86%) of the rev/env gene cassettes were functional. Pseudoviruses generated with pPCR products or corresponding plasmid DNA showed similar sensitivity to six HIV-1 positive sera and three monoclonal antibodies, suggesting neutralization properties are not altered in pPCR pseudovirions. Furthermore, sufficient amounts of pseudovirions can be obtained for a large number of neutralization assays. The new pPCR method eliminates cloning, transformation, and plasmid DNA preparation steps in the generation of HIV-1 pseudovirions. This allows for quick analysis of multiple env genes from HIV-1 infected individuals. [Copyright &y& Elsevier]

Abstract: Neutralizing antibodies (Nabs) are thought to play an important role in prevention and control of HIV-1 infection and should be targeted by an AIDS vaccine. It is critical to understand how HIV-1 induces Nabs by analyzing viral sequences in both tested viruses and sera. Neutralization susceptibility to antibodies in autologous and heterologous plasma was determined for multiple Envs (3–6) from each of 15 subtype-C-infected individuals. Heterologous neutralization was divided into two distinct groups: plasma with strong, cross-reactive neutralization (n =9) and plasma with weak neutralization (n =6). Plasma with cross-reactive heterologous Nabs also more potently neutralized contemporaneous autologous viruses. Analysis of Env sequences in plasma from both groups revealed a three-amino-acid substitution pattern in the V4 region that was associated with greater neutralization potency and breadth. Identification of such potential neutralization signatures may have important implications for the development of HIV-1 vaccines capable of inducing Nabs to subtype C HIV-1. [Copyright &y& Elsevier]