Human leukaemia-associated antigens expressed by acute lymphocytic leukaemias and their detection with heterologous antisera to T, B-, and non-T-non-B subtype AL blasts.

Antisera from rabbits and goats against subtypes of acute lymphocytic leukaemia (ALL with T-cell markers, ALL with B-cell markers, Non-T-non-B ALL) were tested for their specificity in complement-dependent in-vitro cytotoxicity testing. After absorption of the fivefold diluted antisera with erythrocytes and spleen cells of allogenous donors they reacted with ALL cells, but not with leukaemias of other types (AML, CLL, CML), lymphocytes of healthy donors, enriched B-lymphocytes, enriched T-lymphocytes, PHA-stimulated lymphocytes, cord lymphocytes and bone marrow lymphocytes of patients in remission. In the reactions of the antisera against ALL cells the subtype of ALL is of major importance: Six rabbit antisera and one goat antiserum against T-subtype ALL reacted in all 19 tests with the leukaemia cells of 5 patients with T-cell ALL and in all 9 tests with thymocytes of 3 donors, but only in 14 out of 41 tests with the leukaemia cells of 14 Non-T-non-B ALL patients. One antiserum against a B-subtype ALL lysed B-cell ALL (1/1), but not T-cell ALL (0/3), Non-T-non-B-cell ALL (1/5) and thymocytes (0/2). Four antisera against Non-T-non-B-subtype ALL reacted in 22 out of 46 tests with the Non-T-non-B cells of 17 ALL patients, but did not react with the leukaemia cells of 4 children with T-cell ALL (0/16), one child with B-cell ALL (0/1) thymocytes of 2 donors (0/4). The reactions of the anti-ALL sera with fetal liver cells, complete absorbability of the antileukaemic activity of the antisera with fetal tissue and the reactions of an anti-fetal serum with ALL cells point to the existence of fetal antigen components as leukaemia-associated antigens.