Cell Surface Antigens Detected on Mature and Leukemic Granulocytic Populations by Cytotoxicity Testing

Using a microcytotoxicity assay, the serological reactivity of human granulocytes, namely neutrophils and eosinophils, and chronic myeloid leukemia (CML) cells and cultured CML cell lines (K562, NALM-1) were examined. Mature granulocyte forms and cord granulocytes are readily lysed by specific granulocyte cytotoxins that do not react with random T and B lymphocytes, monocytes, red blood cells, or platelets. Furthermore, certain antisera were preferentially cytotoxic for eosinophil-enriched populations. Granulocytotoxin detected antigens on one of three CML blast cell populations tested and K562, but failed to react with NALM-1. By cytotoxicity, mature granulocytes were poor targets for B2-microglobulin and the appropriate HLA antisera although both sera types are absorbed with granulocytes. Furthermore, granulocytes did not possess B-lymphocytes (Ia-like) or blood group A, B, and Rh (D) antigens. Except for K562, both HLA and heterologous B-lymphocyte antisera were cytotoxic for the CML blast cell populations tested.