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AUTHOR
Dimitrij Plachov
Presentation of insulin and insulin A chain peptides to mouse T cells: involvement of cysteine residues.
The requirements for insulin presentation and recognition by A alpha b A beta b- and A alpha b A beta k-restricted mouse T cells were studied using a variety of derivatives of the insulin A chain. It was found that A chain peptides with irreversibly blocked Cys residues are non-stimulatory for the T cells. This suggests that at least one of the Cys residues is essential for recognition. On the other hand, all A chain peptides containing Cys residues modified in a way reversible by reaction with thiols are stimulatory yet differ in antigenic potency. All these A chain derivatives including a 14 amino acid fragment require uptake by antigen presenting cells (APC) for efficient presentation. D…
Processing requirements for the recognition of insulin fragments by murine T cells.
In this study we investigated aspects of antigen processing using insulin and insulin A chain-derived fragments as model antigens in Ab alpha Ak beta-restricted T-cell stimulation. Similarly to other proteins, the immunodominant region of insulin recognized by these T cells is limited in size. It is located on the insulin A chain and encompasses a portion of the molecule that is represented faithfully by peptide A1-14(SSO3-)3. Efficient presentation of intact insulin and its entire A chain is dependent on uptake and processing by APC. Whereas peptides stemming from various globular proteins are known to be presented to T cells by APC without requiring processing, this is not the case with A…