Selective functional depletion of HIV gp120 peptides complexed with MHC from antigen-presenting cells engaged with specific T lymphocytes.
Human T cell lines specific for different peptides of HIV envelope glycoprotein gp120 have been used as probes to identify the availability of functional MHC-peptide complexes on APC. MHC-peptide complexes recognized by T cells specific for peptide 24 (amino acids 225-240) are no longer available on the surface of APC after interaction with irradiated (binding nonproliferating) T cells with the same fine specificity. On the contrary, MHC-peptide complexes recognized by T cells specific for peptide 30 (amino acids 285-300) were functionally available and could stimulate T cells with such a specificity. The reciprocal experiment yielded similar results. The same data were also reproduced with another pair of gp120 peptides. These data demonstrate that upon clustering of peptide-specific T cells with presenting cells presentation of the same peptide to a second cohort of T cells with identical specificity is abolished, suggesting that a selective functional depletion of the MHC-peptide complexes engaged with specific T cells occurs at the surface of the presenting cells. The depletion does not affect other MHC molecules complexed with unrelated peptides.
Manca
F
F
Department of Immunology, University of Genoa, San Martino Hospital, Italy.
D000595:Amino Acid Sequence; D000938:Antigen-Presenting Cells / Q000276:immunology*; D002478:Cells, Cultured; D015488:HIV Antigens / Q000378:metabolism*; D015699:HIV Envelope Protein gp120 / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D066298:In Vitro Techniques; D046911:Macromolecular Substances; D008285:Major Histocompatibility Complex; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
D015488:HIV Antigens; D015699:HIV Envelope Protein gp120; D046911:Macromolecular Substances; D010455:Peptides