Cleaner air in Volgograd.

THE POTENTIAL USE of antibody for diagnostic or therapeutic applications in human cancer may well depend upon the ability to synthesize large quantities of monospecific "anti-tumour" immunoglobulin in vitro. In this respect, the hybridoma technology has produced murine monoclonal antibodies directed against a number of human tumour-associated antigens (Koprowski et al., 1978; Yeh et al., 1979; Kennett & Gilbert, 1979; Levy et al., 1979; Herlyn et al., 1979; Accolla et al., 1980). However, the establishment of hybrid cell lines to produce human antibodies with defined tumour specificities has not yet been successful. There is an alternative method for producing human antibody in vitro by infecting B lymphocytes with EpsteinBarr virus (EBV) to establish human lymphoblastoid cell lines. In 1977, Steinitz et al. and Luzzanti et al. first reported in vitro production of specific human antibody on the synthetic hapten NNP (4-hydroxy3,5-dinitrophenacetic acid) and to heterologous erythrocytes, respectively, from EBV-transformed B lymphoblastoid cells. Following these studies, several other specific antibodies were produced in vitro by EBV transformation, including those to tetanus toxoid (Zurawski et al., 1978), the hapten trinitrophenyl (TNP) (Kozbor et al., 1979), the blood-group antigen Rh (Koskimies, 1979) and to diphtheria toxin (Tsuchiya et al., 1980). We have successfully established lymphoblastoid cell lines that synthesize antibody directed against a human tumour-associated foetal antigen (TAFA) designated as Oncofoetal AntigenI (OFA-I). OFA-I, first described by our laboratory (Irie et al., 1976), is a membrane antigen on various histological types of human cancer cells that cross-reacts with human foetal brain tissue, but has not been found in foetal liver, spleen, and thymus, or on any normal adult cells. OFA-I has been shown to be immunogenic in man, by its ability to provoke humoral antibody in patients with cancer using indirect membrane immunofluorescence (IMIF) (Irie et al., 1976) and immune-adherence (IA) (Irie et al., 1976, 1979b). Recently we reported that the disease-free interval of postoperative Stage II melanoma patients strongly correlates with their serum level of IgM anti-OFA-I (Jones et al., 1981). This fact, coupled with the finding that serum anti-OFA-I is cytotoxic in the presence of either rabbit or human complement to OFA-I+ tumour cells (Sidell et al., 1979a, b), suggests that IgM antiOFA-I could confer some protection against tumour growth in vivo. The ability to produce IgM anti-OFA-I in vitro as described in this report should enable us to define more precisely the role of this TAFA in human cancer.