Selectively reduced tat mRNA heralds the decline in productive human immunodeficiency virus type 1 infection in monocyte-derived macrophages.

The transcription and splicing of human immunodeficiency virus type 1 (HIV-1) mRNA in primary blood monocyte-derived macrophages (MDM) and CD4(+) peripheral blood lymphocytes (PBL) were compared to determine whether any differences might account for the slower noncytopathic infection of cells of the macrophage lineage. The expression of regulatory mRNAs during acute infection of MDM was delayed by about 12 h compared to that of PBL. In each cell type, an increase in spliced viral mRNAs slightly preceded virus production from the culture. Following the peak of productive infection, there was a proportional decrease in the expression of all regulatory mRNAs detected in PBL. In MDM, a dramatic additional decrease specifically in the tat mRNA species heralded a reduction in virus production. This decline in tat mRNA was reflected by a concomitant decrease in Tat activity in the cells and occurred with the same kinetics irrespective of the age of the cells when infected. Addition of exogenous Tat protein elicited a burst of virus production from persistently infected MDM, suggesting that the decrease in virus production from the cultures is a consequence of the reduction in tat mRNA levels. Our results show that modulation of HIV-1 mRNAs in macrophages during long-term infection, which is dependent on the period of infection rather than cell differentiation or maturation, results in a selective reduction of Tat protein levels at the commencement of a persistent, less productive phase of infection. Determination of the mechanism of this mRNA modulation may lead to novel targets for control of replication in these important viral reservoirs.

Association between immune recovery uveitis and a diverse intraocular cytomegalovirus-specific cytotoxic T cell response.

Cytomegalovirus (CMV) causes serious infection in individuals with deficient T cell immunity. In acquired immunodeficiency syndrome, the retina is a major site of progressive infection, despite the availability of therapy that targets CMV. The administration of highly active antiretroviral therapy to suppress human immunodeficiency virus frequently results in resolution of CMV retinitis, but this may be complicated by ocular inflammation termed "immune recovery uveitis" (IRU). To provide insight into the pathogenesis of IRU, the phenotype and specificity of intraocular T cells in a single patient were analyzed. The T cell infiltrate consisted of a diverse population of CD8(+) CMV-specific T cells, but only a minority of these T cells recognized the CMV phosphoprotein 65 and immediate early protein 1, which have been considered major targets of the host response. These results imply that reconstitution of CMV-specific T cells plays a role in IRU and suggest that the specificity of T cells engaged in the control of CMV at local sites of reactivation may be broad.