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Role of interaction of CD2 molecules with lymphocyte function-associated antigen 3 in T-cell recognition of nominal

S Koyasu1, T Lawton, D Novick

  • 1Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA.

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

Insights

The interaction between CD2 molecules and LFA-3 significantly enhances T-cell recognition of nominal antigens like HIV gp120. This CD2-LFA-3 binding stabilizes T-cell and antigen-presenting cell conjugates, crucial for immune responses.

Area of Science:

  • Immunology
  • Cellular Biology
  • Molecular Interactions

Background:

  • T-cell recognition of antigens is critical for adaptive immunity.
  • The interaction between CD2 molecules and lymphocyte function-associated antigen 3 (LFA-3) is known to play a role in T-cell activation.
  • Understanding these molecular interactions can provide insights into immune response modulation.

Purpose of the Study:

  • To investigate the role of CD2-LFA-3 interaction in T-cell recognition of nominal antigens.
  • To determine how CD2-LFA-3 co-stimulation affects the sensitivity of T-cell responses.
  • To elucidate the contribution of CD2-LFA-3 interaction to T-cell and antigen-presenting cell (APC) conjugate formation.

Main Methods:

  • Utilized an HLA-DR4-restricted CD4+ cytotoxic human T-cell clone specific for HIV gp120 as responder cells.
  • Employed murine fibroblasts transfected with human class II MHC and/or LFA-3 as antigen-presenting cells (APCs).
  • Assessed T-cell proliferation, conjugate formation, and the effects of soluble CD2 and antibodies against LFA-3 and CD2.

Main Results:

  • Co-expression of LFA-3 on DR4+ APCs decreased the nominal antigen requirement for T-cell recognition by over 10-fold.
  • CD2-LFA-3 interaction is necessary for antigen-independent conjugate formation, further enhanced by nominal antigen.
  • CD2-LFA-3 interaction stabilizes T-cell-APC conjugates independently of T-cell receptor-MHC interaction.

Conclusions:

  • The CD2-LFA-3 interaction significantly lowers the threshold for T-cell activation by nominal antigens.
  • This interaction plays a crucial role in stabilizing T-cell-APC conjugates, independent of antigen specificity.
  • Reorganization of CD2 molecules during conjugate formation is antigen-independent and not essential for T-cell activation.

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