Janice Clements

Research in the Retrovirus Laboratory focuses on the molecular virology and pathogenesis of lentivirus infections. In particular, the simian immunodeficiency virus (SIV) is used to examine the molecular basis for the pathogenesis of HIV CNS disease. Research projects include studies of viral molecular genetics and host cell genes and proteins involved in the pathogenesis of disease. Further studies of lentivirus infections of macrophages and specific viral pathogenesis in the central nervous system and the lung are of interest. These studies have led us to identify the viral genes that are important in neurovirulence of SIV and the development of CNS disease. The SIV Envelope gene and the NEF gene both play important roles in infection of the CNS. The mechanisms of the action of these proteins in the CNS are complex and are under investigation.   Her group was the first to identify the role of CD4-independent virus entry in the pathogenesis of neurological disease. They have shown that neurovirulent SIV can infect cells in a CD4-independent, CCR5-dependent manner in primary CNS endothelial cells and cell lines that express only CCR5. Furthermore, studies have shown that the Nef protein from the neurovirulent virus interacts with different cellular kinases than the Nef protein from other strains of SIV. Their studies have demonstrated that replication of neurovirulent virus in vivo by quantitation of viral RNA copies in the brain and viral load in cerebral spinal fluid is directly correlated with the development of CNS lesions during SIV infection. Finally, they have shown that virus replication in the CNS is independently regulated from the peripheral blood. Because virus replication in the brain is mainly in macrophages while in the peripheral blood it occurs in lymphocytes, control of viral replication by innate immune responses in the brain is significant. Current research is examining the role of these innate immune responses on restricting viral RNA transcription and gene expression.