A group-specific inhibitor of lysosomal cysteine proteinases selectively inhibits both proteolytic degradation and presentation of the antigen dinitrophenyl-poly-L-lysine by guinea pig accessory cells to T cells
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A limited intralysosomal proteolytic degradation is probably a key event in the accessory cell processing of large protein antigens before their presentation to T cells. With the aid of highly specific inhibitors of proteinases, we have examined the role of proteolysis in the presentation of antigens by guinea pig accessory cells. The proteinase inhibitor benzyloxycarbonyl-phenylalanylalanine-diazomethyl-ketone, which selectively inhibits cysteine proteinases, was used to block this set of enzymes in cultured cells. We demonstrate that the selective inhibition of the cysteine proteinases of antigen-presenting cells causes a profound inhibition of both the proteolytic degradation and the presentation of the synthetic antigen dinitrophenyl-poly-L-lysine. In contrast, the presentation of another synthetic antigen, the copolymer of L-glutamic acid and L-alanine, was enhanced by the same inhibitor. Another inhibitor, pepstatin A, which selectively blocks aspartic proteinases, did not block the presentation of dinitrophenyl-poly-L-lysine. The results identify cysteine proteinases, probably lysosomal, as one of the groups of enzymes involved in antigen processing.
Original language | English |
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Journal | Journal of Immunology |
Volume | 136 |
Issue number | 2 |
Pages (from-to) | 452-8 |
Number of pages | 6 |
ISSN | 0022-1767 |
Publication status | Published - 1986 |
Bibliographical note
Keywords: Animals; Antigen-Presenting Cells; Binding, Competitive; Cysteine Proteinase Inhibitors; Dinitrophenols; Dose-Response Relationship, Immunologic; Guinea Pigs; Immunosuppressive Agents; Lysine; Lysosomes; Pepstatins; Peptides; Peritoneal Cavity; Polylysine; Proteins; T-Lymphocytes; Tuberculin
ID: 9948332