Characterization of anti-Forssman (anti-Fs) antibodies in human sera: their specificity and possible changes in patients with cancer
Young, W.W.; Hakomori, S.I.; Levine, P.
Journal of Immunology 123(1): 92-96
1979
ISSN/ISBN: 0022-1767 PMID: 448159 Document Number: 140551
The majority of normal human sera hemolyze sheep erythrocytes in the presence of complement (hemolyzers), whereas sera of the remaining population do not lyze sheep erythrocytes (nonhemolyzers). The antibodies responsible for this lytic activity are now identified as being specific to glycolipid, predominantly of the Ig-dependent lysis of liposomes containing Fs glycolipid, whereas nonhemolyzer sera reacted very weakly with the same Fs liposomes. The level of hemolytic activity generally paralleled the reactivity of the sera with Fs liposomes. Human anti-Fs did not cross-react with liposomes containing globoside, the precursor to Fs, or blood group A glycolipid. The Co-dependent hemolysis of sheep erythrocytes by hemolyzer sera was specifically inhibited by Fs liposomes but not by A- or globoside liposomes. In 5 of 6 cases tested, hemolysin activity was present in the IgM fraction but not the IgG fraction; in the remaining case the activity was present in the IgG fraction. The presence of Fs glycolipid was previously described in the normal gastrointestinal mucosa of a minor percentage of Taiwanese cancer patients. In most cases, Fs was absent in the normal mucosa but present in the tumors derived therefrom. The sera of cancer patients displayed a decreased anti-Fs reactivity as compared with sera of a control group, suggesting that Fs-positive tumor tissue may affect serum anti-Fs levels.