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Updated: Aug 8, 2026

In Vitro Assay to Evaluate the Impact of Immunoregulatory Pathways on HIV-specific CD4 T Cell Effector Function
09:26

In Vitro Assay to Evaluate the Impact of Immunoregulatory Pathways on HIV-specific CD4 T Cell Effector Function

Published on: October 16, 2013

Human immunodeficiency virus infection is efficiently mediated by a glycolipid-anchored form of CD4

D C Diamond1, R Finberg, S Chaudhuri

  • 1Division of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02115.

Proceedings of the National Academy of Sciences of the United States of America
|July 1, 1990
PubMed

Insights

The CD4 molecule acts as a receptor for HIV. A modified CD4 protein, CD4PI, lacking a membrane anchor, effectively mediates HIV infection, showing the transmembrane region is not essential for viral entry.

Area of Science:

  • Immunology
  • Virology
  • Molecular Biology

Background:

  • The CD4 molecule plays a dual role in cellular function, acting as a receptor for both MHC class II molecules and the human immunodeficiency virus (HIV).
  • CD4 binding to MHC class II enhances T-cell activation, while HIV utilizes CD4 for cellular entry.
  • Understanding the structural requirements of CD4 for HIV binding is crucial for developing antiviral strategies.

Purpose of the Study:

  • To investigate the structural attributes of the CD4 molecule essential for HIV infection.
  • To determine if the membrane-spanning domain of CD4 is necessary for its function as an HIV receptor.

Main Methods:

  • A chimeric molecule, CD4PI, was engineered by linking CD4 to lymphocyte function-associated antigen 3 (LFA-3) via glycosyl-phosphatidylinositol (GPI) anchor, thus lacking a transmembrane domain.
  • Both CD4PI and wild-type CD4 were expressed in the human T-cell line HSB-2.
  • The efficiency of HIV infection in cells expressing CD4PI versus wild-type CD4 was compared.

Main Results:

  • The CD4PI molecule successfully mediated HIV infection in HSB-2 cells.
  • The efficiency of HIV infection mediated by CD4PI was comparable, or even greater, than that of wild-type CD4.
  • These findings indicate that the membrane-spanning region of CD4 is not required for HIV to use it as a receptor.

Conclusions:

  • A lipid-anchored CD4 protein can function effectively as a viral receptor for HIV.
  • The transmembrane domain of CD4 is dispensable for mediating HIV infection.
  • This research provides insights into the structural flexibility of viral receptors and potential targets for therapeutic intervention.

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