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HIV-gp120 can block CD4-class II MHC-mediated adhesion
Y Rosenstein1, S J Burakoff, S H Herrmann
1Division of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA.
Journal of Immunology (Baltimore, Md. : 1950)
|January 15, 1990
Summary
Soluble HIV envelope glycoprotein (gp120) avidly binds to CD4 receptors, inhibiting T-cell immune function. This gp120 binding disrupts CD4+ T-lymphocyte interactions with antigen-presenting cells, contributing to HIV-associated immune dysfunction.
Area of Science:
- Immunology
- Virology
- Cell Biology
Background:
- Human Immunodeficiency Virus (HIV) infection causes immune dysfunction.
- Soluble HIV envelope glycoprotein (gp120) avidly binds to CD4 receptors on T-lymphocytes.
- This binding may inhibit CD4+ T-cell function, a key component of immune response.
Purpose of the Study:
- To assess the impact of gp120 binding on CD4+ T-cell function.
- To investigate the mechanism by which gp120 interferes with T-cell interactions.
- To understand the role of CD4-gp120 interaction in HIV pathogenesis.
Main Methods:
- Assessed CD4+ T-cell function by measuring conjugate formation with artificial target cells (ATC).
- ATCs were lipid vesicles engineered to display MHC class II proteins, the natural ligand for CD4.
- Measured conjugate formation over time and in the presence of varying concentrations of gp120.
Main Results:
- CD4+ T-cells formed conjugates with MHC class II+ ATC in a transient, time-dependent manner (peak at ~30 min).
- Soluble gp120 specifically blocked CD4+ T-cell conjugate formation with class II+ ATC.
- This inhibition by gp120 was concentration-dependent, demonstrating a direct interference with CD4-mediated adhesion.
Conclusions:
- T-lymphocyte adhesion mediated by CD4 is a dynamic process.
- Binding of HIV gp120 to CD4 disrupts normal T-cell adhesion and interaction with antigen-presenting cells.
- gp120-mediated inhibition of CD4 function contributes to the immune dysfunction observed in HIV infection.