Surface antigens on equine sarcoid cells and normal dermal fibroblasts as assessed by xenogeneic antisera

To characterise the expression of surface antigens on equine sarcoid cells compared to normal equine fibroblasts, immune sera were produced in rabbits against transformed cells of a virus-containing sarcoid cell line (Mc-1) and normal dermal fibroblasts, respectively. The specificities of the sera were analysed by antibody-dependent cellular cytotoxicity against 51Cr-labelled target cells using human lymphocytes as effector cells. Anti-Mc-1 antiserum induced strong cytotoxicity against transformed cells of two sarcoid cell lines (Mc-1 and Bay Mc-1), whereas the cytotoxicity against transformed cells of equine testis, or against cells grown in short term or primary cultures derived either from sarcoids or normal dermis was low or absent. In contrast, anti-normal dermal fibroblasts antiserum did not induce antibody-dependent cellular cytotoxicity against Mc-1 or Bay Mc-1 but reacted strongly against both normal fibroblasts and primary cultured cells derived from sarcoids. The apparent specificity of the anti-Mc-1-induced cytotoxicity was confirmed by absorption of the anti-serum with either normal dermal fibroblasts and equine testis cells or Mc-1 cells. Immunoprecipitation of 125I-surface labelled Mc-1 cells by absorbed anti-serum and analysis by SDS-PAGE and autoradiography revealed that anti-Mc-1 antibodies reacted with at least four surface components with a wide range of molecular weights. Immunofluorescence with rabbit anti-human beta 2mu serum indicated that Mc-1 cells in contrast to equine lymphocytes and fibroblasts did not express class 1 major histocompatibility complex antigens.(ABSTRACT TRUNCATED AT 250 WORDS)