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Different endosomal proteolysis requirements for antigen processing of two T-cell epitopes of the M5 protein from

A A Delvig1, J H Robinson

  • 1Department of Immunology, School of Microbiological, Virological, and Immunological Sciences, The Medical School, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne, Tyne and Wear, NE2 4HH, United Kingdom.

The Journal of Biological Chemistry
|March 7, 1998
PubMed

Insights

Streptococcus pyogenes M5 protein processing involves different endosomal pathways and proteases for distinct T-cell epitopes. This impacts major histocompatibility complex class II antigen presentation.

Area of Science:

  • Immunology
  • Microbiology
  • Molecular Biology

Background:

  • Streptococcus pyogenes M5 protein is crucial for T-cell responses.
  • Antigen processing is essential for major histocompatibility complex class II presentation.

Purpose of the Study:

  • To investigate the endosomal proteolysis of Streptococcus pyogenes M5 protein.
  • To understand the processing mechanisms of two T-cell epitopes (17-31 and 308-319).

Main Methods:

  • Studied proteolysis of M5 protein from viable Streptococcus pyogenes.
  • Analyzed processing of soluble recombinant M5 protein.
  • Investigated the role of endosomal acidification and various proteases (serine, cysteine, aspartic).

Main Results:

  • Epitope 17-31 processing by serine proteinases was independent of endosome acidification.
  • Epitope 308-319 processing required serine, cysteine, and aspartic proteinases, and endosome acidification.
  • Different intracellular proteases and compartments were involved in processing the two epitopes.

Conclusions:

  • Antigen processing of M5 protein epitopes occurs in distinct endosomal compartments.
  • Differential protease activities mediate the processing of T-cell epitopes on Streptococcus pyogenes M5 protein.

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