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T J Tsomides

Publications and source records attributed to T J Tsomides.

3 recordsLinked to original sources
PubMed1992

A naturally occurring peptide recognized by alloreactive CD8+ cytotoxic T lymphocytes in association with a class I MHC protein.

The antigenic structures that initiate T cell responses to foreign (allogeneic) cells have long attracted considerable interest. We have purified and sequenced a peptide from mouse spleen that is recognized in association with the class I MHC protein H-2Ld by 2C, an alloreactive CD8+ T cell clone. The peptide (LSP-FPFDL) greatly enhances the susceptibility of Ld+ cells to lysis by 2C, and this activity is completely blocked by a clonotypic antibody against the 2C T cell receptor. Thus, this study characterizes the naturally occurring peptide moiety of an MHC-I/peptide complex recognized by alloreactive CD8+ T cells. The peptide, which occurs in the thymus of MHC-disparate mice, can be used to study T cell development in mice expressing transgenes for the 2C T cell receptor.

Amino Acid Sequence↗
PubMed1991

An optimal viral peptide recognized by CD8+ T cells binds very tightly to the restricting class I major histocompatibility complex protein on intact cells but not to the purified class I protein.

CD8+ cytotoxic T lymphocytes recognize cell surface complexes formed by class I major histocompatibility complex (MHC-I) glycoproteins and antigenic peptides. We have identified a peptide nonamer (termed IV9) derived from the human immunodeficiency virus that is over a millionfold more active (at subpicomolar concentrations) than peptide analogues longer or shorter by one or two amino acid residues. Although IV9 does not detectably bind to isolated MHC-I molecules as measured by equilibrium dialysis, we quantitated its specific binding in unaltered form to MHC-I on intact cells. Less than 1% of cell surface MHC-I forms complexes with IV9, which suffices to trigger maximal cytotoxic T-lymphocyte activity. By contrast, a peptide dodecamer that includes the IV9 sequence and is active at micromolar concentrations does not bind to MHC-I on intact cells, raising the possibility that this longer peptide undergoes processing. Using stoichiometrically iodinated IV9 to obviate the ambiguities associated with trace labeling methods, we measured the dissociation kinetics of purified peptide/MHC-I complexes isolated by affinity chromatography and found these complexes to be exceedingly stable (t1/2 = 200-600 hr).

Amino Acid Sequence↗