Differential effects of interleukin-13 on cytomegalovirus and human immunodeficiency virus infection in human alveolar macrophages.

Alveolar macrophages, which form a principal line of defense against a variety of pulmonary pathogens, may themselves be infected by viruses like human immunodeficiency virus-1 (HIV-1), which impair their defensive functions. Interleukin-13 (IL-13), a multifunctional cytokine, has been considered for therapeutic use based on its potent inhibition of HIV-1 in these cells. We have further examined the effects of IL-13 on alveolar macrophages under conditions that reflect those seen in acquired immune deficiency syndrome, where this cell type is often infected by the opportunistic pathogen human cytomegalovirus (HCMV). Alveolar macrophages exposed to both HCMV and HIV-1 consistently exhibited higher levels of HIV-1 replication than cells exposed to HIV-1 alone. HIV-1 production was strongly suppressed in alveolar macrophages treated with IL-13 regardless of whether or not the cultures were coinfected with HCMV. However, IL-13 treatment markedly enhanced the expression of HCMV in otherwise latently infected macrophages in a dose dependent manner. These unexpected differential effects of IL-13 on host-virus interactions are important considerations in guiding its potential therapeutic applications.

Loss of T cell receptor Vbeta repertoires in HIV type 1-infected SCID-hu mice.

Late-stage HIV-1 disease in humans has been associated with perturbations of the T cell receptor (TCR) Vbeta repertoire. It is not known if the observed loss of certain Vbeta families is attributable directly to HIV-1 infection or whether this is a consequence of multiple opportunistic infections. Putative HIV-1-associated superantigens have been postulated to be the cause of the perturbed TCR Vbeta repertoire and the subsequent CD4+ T cell depletion in HIV-1-infected humans. In this study, we examined the human TCR Vbeta repertoire in SCID-hu mice, housed in a pathogen-free environment and infected with a molecularly cloned virus strain, to ascertain directly the effect of HIV-1 on the human TCR Vbeta repertoire in the absence of other infectious agents. We demonstrate that mock-infected human thymus/liver (Thy/Liv) implants in SCID-hu mice have complete TCR Vbeta repertoires, reflective of a normal human thymus. However, HIV-1-infected implants in SCID-hu mice had depleted TCR Vbeta repertoires, corresponding with thymocyte depletion. These results indicate that HIV-1-specific mechanisms are the cause of the TCR Vbeta repertoire depletion in infected implants. However, these thymocyte depletions were not restricted to specific TCR Vbeta subsets. These results are not consistent with the hypothesis that HIV-1 acts as a superantigen in vivo. The disruption of the TCR Vbeta repertoire in the human Thy/Liv implants of the SCID-hu mice suggests that HIV-1 infection may be influencing T cell development in the thymus, contributing to both the overall CD4+ T cell depletion in AIDS and limited TCR repertoire diversity.

Efficient transduction of human neurons with an adeno-associated virus vector.

An adeno-associated virus vector containing a lacZ gene driven by a CMV immediate-early promoter (AAV beta-gal) was evaluated with respect to its transduction efficiency and integration ability in nondividing human NT neurons. A dose-dependent pattern in transduction efficiency of the AAV beta-gal was demonstrated immunocytochemically, with up to 100% of the neurons expressing the gene product. No neurotoxic effects of the vector were detected. Quantitative PCR analyses of high molecular weight cellular DNA from the transduced neurons indicated that the copy number of the AAV beta-gal genome increased gradually in a time dependent manner, suggesting a slow but progressive rate of vector integration over a period of approximately 1 week following transduction. Equal or greater transduction efficiency of the AAV beta-gal into NT neurons than into a standard target cell line indicated that the NT neurons were readily susceptible to AAV-mediated gene transfer. This study demonstrates that AAV-based vectors can efficiently transduce and stably express a foreign gene in post-mitotic human neurons.

The T-cell receptor V beta repertoire in naive and human immunodeficiency virus-1 (HIV-1) infected chimpanzees.

Using a panel of human T-cell receptor (TCR) variable region beta chain (V beta) polymerase chain reaction (PCR) primers, we performed cross-sectional and longitudinal analyses of the TCR V beta repertoire in naive and HIV-1 infected chimpanzees. We demonstrate that our TCR PCR primer panel will support amplification of chimpanzee cDNA from most of the TCR V beta families. However, no differences in TCR V beta expression were found between the naive and HIV-1 infected chimpanzees, unlike the TCR V beta repertoire perturbation found in HIV-1 infected human subjects. This finding suggests that a complete TCR repertoire in HIV-1 infected chimpanzees is associated with the maintenance CD4+ T-cell numbers and lack of progression to AIDS.

Random depletion of T cells that bear specific T cell receptor V beta sequences in AIDS patients.

A cross-sectional PCR analysis of the TCR V beta repertoires in HIV-1 seronegative controls and HIV-1 infected individuals with either clinically or immunologically defined AIDS [1] was performed to examine the proposed superantigen model for HIV-1 pathogenesis. In contrast to previous reports, we find neither uniform specific losses nor uniform clonal expansions of particular TCR V beta gene families in subjects with AIDS. Instead our study, which was designed specifically to qualitatively determine the presence or absence of TCR V beta families in both subject populations, indicates an overall diminution in the expression of TCR V beta gene families in HIV-1 infected individuals with AIDS compared with controls. This is commensurate with the decrease in CD4 T cells in the AIDS population. Our data are therefore not directly suggestive of a common superantigen model of HIV-1 induced T cell clonal depletion or anergy, but instead emphasize a broad decrease in signals throughout the TCR V beta repertoire in AIDS versus control groups. This random depletion in the TCR V beta repertoire is most likely caused by aspects of HIV-1 pathogenesis other than virus-encoded superantigens.