The Journal of Immunology, Vol 154, Issue 1 128-136, Copyright © 1995 by American Association of Immunologists

ARTICLES

Characterization of fibroblasts with a unique defect in processing antigens with disulfide bonds

BJ Merkel, R Mandel, HJ Ryser and KL McCoy
Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond 23298.

A chinese hamster ovary (CHO) fibroblast, transfected with murine MHC class II genes, inefficiently stimulated CD4+ Th cells specific for OVA, hen egg lysozyme (HEL), and pork insulin which contain disulfide bonds. However, the fibroblasts elicited a T cell response to lambda repressor, which lacks disulfide bonds, and efficiently presented synthetic peptides. A somatic cell hybrid WALC, generated by fusing the hamster fibroblast with a murine L cell fibroblast, very efficiently processed OVA and HEL, suggesting that impaired processing was genetically complemented and was a recessive trait. The hamster fibroblasts were capable of processing two distinct denatured forms of OVA and carboxymethylated HEL, either as effectively or more efficiently than the B lymphoma cell. The CHO cells also displayed diminished disulfide reduction of an endocytosed [125I]tyramine linked to poly-(D-lysine) through a disulfide spacer compared with that of the cell hybrid, providing direct evidence for defective reductive cleavage by the CHO cells. Diminished aspartic acid-mediated proteolysis of Ag could not account for the phenotype, because cell lysates and separated organelles from the fibroblast possessed higher acidic aspartyl proteolytic activity than lysates and organelles from a B lymphoma cell. Thus, CHO cells exhibit a defect in processing Ag with disulfide bonds which is consistent with the impaired intracellular reduction of the disulfide bonds in endocytosed macromolecules.

This article has been cited by other articles:

				G. Sinnathamby, M. Maric, P. Cresswell, and L. C. Eisenlohr Differential Requirements for Endosomal Reduction in the Presentation of Two H2-Ed-Restricted Epitopes from Influenza Hemagglutinin J. Immunol., June 1, 2004; 172(11): 6607 - 6614. [Abstract] [Full Text] [PDF]

				P. Li, M. A. Haque, and J. S. Blum Role of Disulfide Bonds in Regulating Antigen Processing and Epitope Selection J. Immunol., September 1, 2002; 169(5): 2444 - 2450. [Abstract] [Full Text] [PDF]

				M. A. Haque, J. W. Hawes, and J. S. Blum Cysteinylation of MHC Class II Ligands: Peptide Endocytosis and Reduction Within APC Influences T Cell Recognition J. Immunol., April 1, 2001; 166(7): 4543 - 4551. [Abstract] [Full Text] [PDF]

				B. Arunachalam, U. T. Phan, H. J. Geuze, and P. Cresswell Enzymatic reduction of disulfide bonds in lysosomes: Characterization of a Gamma-interferon-inducible lysosomal thiol reductase (GILT) PNAS, January 18, 2000; 97(2): 745 - 750. [Abstract] [Full Text] [PDF]

				T. A. Lewis2, C. B. Hartmann, and K. L. McCoy Gallium Arsenide Modulates Proteolytic Cathepsin Activities and Antigen Processing by Macrophages J. Immunol., September 1, 1998; 161(5): 2151 - 2157. [Abstract] [Full Text] [PDF]

				U. T. Phan, B. Arunachalam, and P. Cresswell Gamma-Interferon-inducible Lysosomal Thiol Reductase (GILT). MATURATION, ACTIVITY, AND MECHANISM OF ACTION J. Biol. Chem., August 18, 2000; 275(34): 25907 - 25914. [Abstract] [Full Text] [PDF]

				K. Honey, M. Duff, C. Beers, W. H. Brissette, E. A. Elliott, C. Peters, M. Maric, P. Cresswell, and A. Rudensky Cathepsin S Regulates the Expression of Cathepsin L and the Turnover of gamma -Interferon-inducible Lysosomal Thiol Reductase in B Lymphocytes J. Biol. Chem., June 15, 2001; 276(25): 22573 - 22578. [Abstract] [Full Text] [PDF]