Nonspecific cytotoxic cells in fish: antigenic cross-reactivity of a function associated molecule with the intermediate filament vimentin.
Nonspecific cytotoxic cells (NCC) in fish may lyse tumor cells and protozoan parasites in a similar fashion as their mammalian NK counterparts. Previous studies have shown that recognition and binding by NCC may be mediated by a receptor. In the present study the putative receptor or function-associated molecule (FAM) on NCC was shown to contain antigenic cross-reactivity with the mammalian intermediate filament vimentin. This was accomplished by comparing the specificity of anti-FAM monoclonal antibody 5C6 with commercially available anti-vimentin mabs V9 and 13.2 and with a polyclonal anti-vimentin antiserum. Tissue distribution studies indicated that the anti-vimentin antibodies bound to significantly fewer (< 50%) anterior kidney, spleen, kidney, and brain cells than mab 5C6. These mabs, however, produced inhibition of NCC lysis of IM-9 target cells. Conditions of mab incubation (with NCC) which were previously shown to modulate NCC cytotoxicity by 5C6 also produced large increases in NCC lysis of IM-9 targets in the presence of mabs V9 and 13.2. The determinant(s) recognized by these antibodies is present on the cell membrane. Microscopic examination of nonpermeabilized or acetone-treated and antibody-stained cells demonstrated that acetone permeabilization produced a 28-32% increase in staining (due to intracellular binding) compared to the staining of viable cells. Biochemical analysis of the cross-reactive antigens was done using analytical 2D SDS-PAGE and Western blot experiments. Mab 5C6 detected a 32- to 35-kDa protein (pI 6.3-6.5) in NCC extracts. Anti-vimentin mab 13.2 recognized a 57-kDa vimentin protein which had a relatively broad pI range (pH 6.3-6.7). Mab 13.2 also cross-reacted (in the same Western blot) with the NCC receptor protein (pI = pH 6.3-6.5). These data indicate that the FAM on NCC/NK cells contain vimentin-like antigenic determinants which may function in target cell binding.
Jaso-Friedmann
L
L
Department of Medical Microbiology, College of Veterinary Medicine, University of Georgia, Athens 30602.
Leary
J H
JH
Evans
D L
DL
D000818:Animals; D000911:Antibodies, Monoclonal; D000941:Antigens / Q000737:chemistry*; D002461:Cell Line, Transformed; D003429:Cross Reactions; D003602:Cytotoxicity, Immunologic; D005260:Female; D006801:Humans; D007059:Ictaluridae / Q000276:immunology*; D007668:Kidney / Q000276:immunology; D007694:Killer Cells, Natural / Q000276:immunology*; D008297:Male; D014746:Vimentin / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000941:Antigens; D014746:Vimentin