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Updated: Jul 29, 2026

Generation of Human Alloantigen-specific T Cells from Peripheral Blood
09:47

Generation of Human Alloantigen-specific T Cells from Peripheral Blood

Published on: November 21, 2014

Metabolically active antigen presenting cells are required for human T cell proliferation in response to the

M A Tomai1, E H Beachey, G Majumdar

  • 1VA Medical Center, Memphis, TN 38104.

FEMS Microbiology Immunology
|February 1, 1992
PubMed

Insights

Streptococcal M protein acts as a superantigen, activating T cells. It requires accessory cells with MHC class II but not processing for T cell activation, suggesting direct complex formation.

Area of Science:

  • Immunology
  • Microbial Pathogenesis

Background:

  • Group A Streptococcus M protein is a superantigen activating T cells expressing specific V beta elements of the T cell receptor (TCR).
  • Understanding the molecular and cellular presentation requirements for M protein superantigens is crucial for elucidating T cell activation pathways.

Purpose of the Study:

  • To investigate the molecular and cellular requirements for the presentation of M protein (pep M5) to T cells.
  • To determine the role of accessory cells (AC) and antigen-presenting cells (APC) in T cell activation by pep M5.

Main Methods:

  • Utilized a 22 kDa fragment of M protein (pep M5) to study T cell activation.
  • Investigated the necessity of accessory cells expressing MHC class II molecules.
  • Examined the role of antigen processing by APCs.
  • Assessed the impact of paraformaldehyde (PF) fixation on APCs and T cell proliferation.
  • Evaluated the effect of adding recombinant interleukin-1 (rIL-1) and IL-6.

Main Results:

  • Accessory cells expressing MHC class II molecules were essential for T cell activation by pep M5.
  • Antigen processing by APCs was not required for T cell proliferation induced by pep M5.
  • PF-fixed APCs showed impaired T cell proliferation but maintained IL-2 production; this was restored by rIL-1 and IL-6.
  • PF-fixation of Raji B lymphoma cells did not impede pep M5 presentation to human T cells.

Conclusions:

  • Pep M5 directly associates with HLA class II molecules, forming a complex that induces IL-2 production.
  • Optimal T cell proliferation requires additional signals from accessory cells beyond the M protein-HLA class II complex.

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