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There are approximately 33.4 million adults living with HIV worldwide of which an estimated 15.7 million are women. Although there has been enormous progress in the therapy of HIV/AIDS, treatment is not curative. Prevention is therefore of paramount importance, but vaccine-based and microbicidal approaches are still in their infancy. Since women acquire the virus largely through sexual intercourse, we developed liposomal systems potentially suitable for intra-vaginal use to prevent HIV-1 infection. We formulated liposomes from a range of naturally-occurring and synthetic lipids with varying physicochemical properties, and tested their ability to inhibit infection of transformed cells that express receptors specific to the virus. We identified formulations with the most favorable balance between decreasing HIV infection and causing cytotoxicity (i.e. therapeutic index). The therapeutic index improved with increasing cardiolipin content, and degree of unsaturation. Tissue reaction to these formulations was benign after intra-vaginal instillation in an in vivo female mouse model. These results support the potential use of cardiolipin-based liposomes enriched with synthetic lipids as microbicides for the prevention of HIV infection in women. © 2011 Elsevier Ltd.

Previous studies have shown that a major block to HIV-1 replication in common marmosets operates at the level of viral entry and that this block can be overcome by adaptation of the virus in tissue-cultured cells. However, our current studies indicate that HIV-1 encounters additional postentry blocks in common marmoset peripheral blood mononuclear cells. Here, we show that the common marmoset APOBEC3G (A3G) and BST2 proteins block HIV-1 in cell cultures. Using a directed-evolution method that takes advantage of the natural ability of HIV-1 to mutate during replication, we have been able to overcome these blocks in tissue-cultured cells. In the adapted viruses, specific changes were observed in gag, vif, env, and nef. The contribution of these changes to virus replication in the presence of the A3G and BST2 restriction factors was studied. We found that certain amino acid changes in Vif and Env that arise during adaptation to marmoset A3G and BST2 allow the virus to replicate in the presence of these restriction factors. The changes in Vif reduce expression levels and encapsidation of marmoset APOBEC3G, while the changes in Env increase viral fitness and discretely favor cell-to-cell transmission of the virus, allowing viral escape from these restriction factors

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(DLPS) 5571095.0054.009, http://name.umdl.umich.edu/5571095.0054.009, http://quod.lib.umich.edu/t/text/accesspolicy.html, Where applicable, subject to copyright. Other restrictions on distribution may apply. Please go to http://www.umdl.umich.edu/ for more information.

The FLB-10 provirus represents a full-length molecular clone derived from SIVmac 251 simian immunodeficiency virus. The molecularly cloned virus is replication-competent in vitro and is cytopathic for CEMX174 lymphocytes and primary macaque peripheral blood lymphocytes. Complete nucleotide sequence reveals that the FLB-10 clone contains mutations compromising expression of the vpr, nef and env genes. Therefore, vpr an nef gene products are not necessary for the in vitro replication or cytopathic effect of SIVmac. Virus stocks were inoculated into several cynomolgus monkeys and one juvenile rhesus macaque. While none of the cynomolgus monkeys have developed an infection over one year post-inoculation, the injected macaque became infected and developed a fatal immunodeficiency syndrome. These results will stimulate further studies with larger numbers of animals to address whether vpr or nef reversions occur to allow in vivo SIV replication.

We have developed a novel technique for rapidly studying microheterogeneity in a population of primate immunodeficiency viruses. Proviruses are rapidly cloned by using an integration - competent cytoplasmic extract from infected cells and integration - sensitive undersize cloning vectors based on bacteriophage lambda. The details of this cloning system are presented. This method yields many clones of integrated proviral DNA, each of which represents an independent clone of provirus contained in the original infected cell population. The utility of this vector to characterize in vitro integration products of a primate immunodeficiency virus (HIV-1) are illustrated as an example.

Molecular characterization of the SIV mac 251 clone that exhibits in vitro replication competence, but poor in vivo replication ability was initiated by complete nucleotide sequence determination. Defects in the vpr, nef and env genes were noted and will be the focus of future efforts to restore in vivo replication competence of this cloned virus. (js)

Infectious Simian Immunodeficiency Virus (mac) proviruses have been cloned and are being characterized for pathogenic potential in vivo. Mutations in the genes encoding regulatory functions will be made to define the role of novel lentivirus genes in in vitro and in vivo replication and pathogenesis. Keywords: Virology; Molecular biology; Biochemistry; Human immunodeficiency virus; HTLV-IV; STLV-III; SIMIAN AIDS, Deoxyribonucleic acids, Plasmics, Reverse transcriptase, Cytopathology. (aw)