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Adenoviral Transduction of Naive CD4 T Cells to Study Treg Differentiation
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Signals transduced through the CD4 molecule interfere with TCR/CD3-mediated ras activation leading to T cell

S M Tamma1, N Chirmule, T W McCloskey

  • 1Department of Pediatrics, North Shore University Hospital-New York University School of Medicine, Manhasset, New York 11030, USA.

Clinical Immunology and Immunopathology
|November 5, 1997
PubMed

Insights

HIV-1 envelope glycoproteins gp160 inhibit T cell signaling by blocking key intracellular events. This leads to T cell anergy and apoptosis, contributing to immune dysfunction in HIV-1 infection.

Area of Science:

  • Immunology
  • Molecular Biology
  • Virology

Background:

  • HIV-1 envelope glycoproteins, like gp120 and gp160, interact with CD4 molecules on T cells.
  • This interaction is known to inhibit T cell receptor-CD3 (TCR/CD3) complex-mediated IL-2 secretion.

Purpose of the Study:

  • To investigate the intracellular mechanisms underlying the inhibitory effects of HIV-1 gp160 on T cell signaling.
  • To understand how gp160 binding to CD4 impacts T cell activation and function.

Main Methods:

  • Purified CD4+ T cells from healthy donors were pretreated with HIV-1 gp160.
  • Cells were activated using anti-CD3 monoclonal antibody (mAb).
  • Intracellular signaling events (tyrosine phosphorylation, ras activation) and biological outputs (cytokine secretion, cell death) were analyzed.

Main Results:

  • Pretreatment with gp160 significantly inhibited tyrosine phosphorylation of p59(fyn) and PLC-gamma1.
  • gp160 suppressed ras activation and TNF-alpha secretion in anti-CD3 mAb-activated CD4+ T cells.
  • A subset of gp160-exposed CD4+ T cells underwent activation-induced cell death (apoptosis).

Conclusions:

  • HIV-1 gp160 binding to CD4 alters TCR/CD3-induced signal transduction pathways.
  • This alteration leads to T cell anergy and apoptosis, resulting in functional deficiency of CD4+ T cells.
  • The findings elucidate a key mechanism of immune impairment in HIV-1 infection.

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