Characterization of a xenoantiserum produced against three molar KCL-solubilized antigens obtained from a non-T, non-B (pre-B) acute lymphoblastic leukemia cell line

Antisera were produced in rabbits to 3 M KCl solubilized antigens of a recently established leukemia cell line. The cell line (NALM-6-M1) was established from an individual with acute lymphoblastic leukemia (ALL), and has the characteristics of a pre-B-cell, i.e., it is cytoplasmic IgM⁺, surface immunoglobulin^-, anti-thymocyte serum^- (CIgM⁺,SIg^-,ATS^-). One unabsorbed antiserum did not react with T cells, and after a single absorption with a B lymphoblastoid cell line (positive for p23,30, an Ia-like antigen), the antiserum reacted with cells from eight of 10 patients with non-T, non-B ALL and cells from two of two patients with chronic myelogenous leukemia in lymphoid blast crisis (CML-LBC). The absorbed antiserum did not react with surface immunoglobulin⁺ chronic lymphocytic leukemia (SIg⁺ CLL) cells; acute myelogenous leukemia (AML) cells; anti-thymocyte serum ⁺, E rosette⁺, acute lymphoblastic leukemia (ATS⁺, E⁺ ALL) cells; cells from patients with chronic myelogenous leukemia in myeloid in myeloid blast crisis (CML-MBC); normal peripheral blood T cells; PHA induced blasts; leukemia T cell lines; or B lymphoblastoid cell lines. The specificity of the absorbed antiserum suggests that it was detecting antigens of non-T, non-B ALL and CML-LBC, and may be recognizing a 'common' ALL antigen. We conclude that 3 M KCl solubilization of membrane antigens from the NALM-6-M1 leukemia cell line provides an effective immunogen for producing antisera reactive with non-T, non-B ALL and CML-LBC. This offers an approach to the biochemical characterization of the antigen(s) common to these two leukemias and allows further evaluation of the relationship between the common ALL antigen and antigens of normal and malignant cells of the pre-B phenotype.