Skin reaction and antibody responses in guinea-pigs sensitized to human leukaemia cells or their nuclei in combination with Bacillus Calmette-Guérin.

Guinea-pigs sensitized by subcutaneous injection of chronic lymphatic leukaemia (CLL) cells combined with Bacillus Calmette-Guérin (BCG) displayed good skin reacitons 24 and 48 h after challenge with CLL cells. Equally good responses were also demonstrated using nuclei from the leukaemic cells in combination with BCG. These reactions were significantly greater than those produced in the same manner but without BCG. Sera form the animals were examined for the presence of antibodies against CLL cells by cytotoxicity and immunofluorescence techniques. Only samples from guinea-pigs innoculated with CLL cells were found to contain significant antibodies. Histological examination showed that whereas leukaemic cells persisted at the sensitizing injection site leukaemic cell nuclei could not be visualized. It is suggested that because leukaemic cell nuclei in combination with BCG are able to induce good skin reactivity without provoking a vigorous humoral antibody response they may have possible advantages over leukaemic cells when used for immunotherapy.