A role of Ia-associated invariant chains in antigen processing and presentation

• Published in: Cell Vol. 56; no. 4; pp. 683 - 689
• Main Authors: STOCKINGER, B, PESSARA, U, RONG HWA LIN, HABICHT, J, GREZ, M, KOCH, N
• Format: Journal Article
• Language: English
• Published: Cambridge, MA Cell Press 24.02.1989
• Subjects: Animals; Antigen-Presenting Cells - physiology; Antigens; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Histocompatibility antigens (hla, h-2 and other systems); Histocompatibility Antigens Class II - genetics; Histocompatibility Antigens Class II - physiology; In Vitro Techniques; L Cells (Cell Line); Mice; Molecular immunology; Molecular Weight; Precipitin Tests; Restriction Mapping; RNA Splicing; Transfection; Virus; Complement C5; Proteins; Antigen presentation; Cell line; Transfection; Splicing; Major histocompatibility system; Orthomyxoviridae; Helper cell; Genetic engineering; Influenzavirus
• ISSN: 0092-8674; 1097-4172
• DOI: 10.1016/0092-8674(89)90590-4

Most native antigens require processing in a cellular compartment for efficient presentation to T helper cells. The cellular elements that permit processing are not known. We investigated a possible role of the class II MHC-associated invariant chains in antigen processing. Fibroblast cells that were transfected with class II genes were compared with fibroblasts supertransfected with the invariant chain gene for their capacity to present the fifth component of complement (C5) to C5-specific class II restricted T cell clones or influenza virus protein to a virus-specific T cell clone. Only fibroblasts supertransfected with the invariant chain gene were able to present native antigen, even at very low antigen concentration, whereas both fibroblast types could present cyanogen bromide-fragmented C5 or the virus peptide. Presentation of intact antigen but not of fragmented antigen was totally abrogated by treatment of fibroblasts with chloroquine. The invariant chain gene encodes two polypeptides, li31 and li41. Expression of either li31 or li41 was sufficient to render class II-expressing fibroblasts capable of presenting intact antigen.