Wide distribution of rat hepatoma asialo GM1 and its different responses to anti-asialo GM1 antibody-mediated in vitro and in situ cell killing.

By means of TLC immunostaining with anti-asialo GM1 antiserum and conventional structural analyses including exoglycosidase treatment, permethylation and negative ion FABMS, asialo GM1 was found to be widely distributed in rat ascites hepatomas, AH130, AH109A, AH44, AH272, AH41C, AH60C, AH414, AH7974, AH66, AH66 alpha F, AH66F and AH13, and Yoshida sarcoma cells. However, reactivity of asialo GM1, when measured by flow cytometry and complement-mediated cytotoxicity assay with anti-asialo GM1 antiserum, was only observed on AH13 and AH66F, and did not necessarily correspond to the concentration of asialo GM1 on the cells, indicating a cryptic or unreactive nature of glycosphingolipids with respect to their antibodies. On the other hand, although rats injected with 10(7) cells of AH66F died within 7 days, treatment of the rats with anti-asialo GM1 antiserum was found to be effective for their cure or for prolonging their survival, indicating an in situ cytotoxic effect of antiserum. For the in situ cytotoxicity, the timing and period of injection and the dose of antiserum were found to be important.