Heteroantiserum against acute lymphocytic leukemia raised to the lymphoblastoid cell line NALM-1

Antisera have been raised in rabbits to the lymphoblastoid cell line NALM 1 precoated with anti-lymphocyte serum (ALS). Following absorption with chronic lymphocytic leukemia cells (CLL) the antisera reacted mainly with acute lymphocytic leukemia (ALL) cells, and were very similar in specificity to antisera raised to ALL cells precoated with ALS. Leukemia cells from the following numbers of patients were positive for the anti-NALM 1 sera in a complement-dependent cytotoxicity test; 11/14 ALL, 3/15 acute myelocytic leukemia (AML), 1/5 chronic myelocytic leukemia (CML) and 0/8 CLL. Normal B and T peripheral blood lymphocytes were negative. The titer of the anti-NALM 1 sera against positive cells was 1:64 to 1:256 whereas the undiluted sera did not react with negative cells. Ten out of 11 of the positive ALL cells were of the non-B non-T type. However, cells from 1/4 T ALL patients and a cultured T ALL line 8402 were also positive. Six of 12 cultured lymphoblastoid cell lines were positive, all of which were of malignant origin. The molecular weight of the ALL antigen detected by anti-NALM-1 serum was determined by immunoprecipitation and sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) to be approximately 98,000 daltons.