The breakdown of the cytokine network subsequent to human immunodeficiency virus infection

Abstract

The acquired immunodeflciency syndrome (AIDS) is a clinically multifaceted disease induced by infection with the human immunodeficiency virus (HIV). HIV infection results in a complex pattern of immunologic alterations that leads to the development of AIDS in the majority of HIV seropositive (HIV+) individuals. The reduction in CD4 T lymphocyte counts is the hallmark of HIV infection; nevertheless, long before the reduction in CD4 counts reaches critical levels, a series of profound and complex defects that impair the function of CD4 T lymphocytes can be detected. Thus, HIV infection is characterized by quantitative and qualitative defects affecting CD4 T lymphocytes. It was suggested recently that programmed cell death (PCD) is an important mechanism leading to CD4 depletion in HIV infection, and that susceptibility of peripheral lymphocytes to PCD is differentially regulated by diverse cytokines. Thus, type 1 cytokines would protect CD4 lymphocytes against PCD, whereas type 2 cytokines would not protect against, and could augment, PCD. We suggest that the qualitative alterations of the immune response provoke the CD4 depletion characteristic of HIV disease via type 2 cytokinemediated augmentation of PCD, and are therefore ultimately responsible for the progression of HIV infection. Finally, we summarize recent data showing that three correlates of disease progression: emergence of HIV strains with syncitium-inducing ability (SI), type 1-to-type 2 cytokine shift, and CD4 depletion, are significantly associated, suggesting a complex interconnected virologic-immunologic pathogenesis of HIV infection.

In VivoSelection of CD4+T Cells Transduced with a Gamma-Retroviral Vector Expressing a Single-Chain Intrabody Targeting HIV-1 Tat

“…Selection of transduced cells has been predicted to be stronger when the inhibitor prevents viral infection rather than just interferes with viral production (von Laer et al, 2006). This would be correct if death of CD4 + T lymphocytes in HIV infection was primarily due to direct infection; however, some reports suggest that toxicity to uninfected bystander CD4 + T cells may also play an important role in the depletion of CD4 + T cells (Clerici et al, 2003). Only a few anti-HIV gene therapy clinical trials (Woffendin et al, 1996;Morgan et al, 2005;Podsakoff et al, 2005) have shown a selective advantage of the therapeutic vector in vivo, whereas no clear evidence for a preferential survival of cells expressing anti-HIV genes was observed in a number of other trials (Donahue et al, 1998;Kang et al, 2002;Amado et al, 2004;Levine et al, 2006;van Lunzen et al, 2007;Mitsuyasu et al, 2009;DiGiusto et al, 2010).…”