The overall objective of this research is an in-depth analysis of human leukemia-associated cell membrane components for developing immunological probes to identify the molecular mechanisms involved in hemopoietic cellular regulation and leukemogenesis. Analyses will exploit a panel of antibodies to leukemia cell surface antigens developed previously by this laboratory that include monoclonal antibodes directed at the common ALL antigen (CALLA, gp100), two non-CALLA ALL antigens (gp24 and """"""""clone 24,"""""""" both shown to be distinct by lysostripping experiments), and a heteroantiserum directed at a T-ALL antigen (gp100). Specific biochemical characteristics of each molecule will be determined using HPLC and peptide mapping. The contribution of carbohydrate moieties to antigenicity will be addressed uaing specific degradation of carbohydrates with enzymes. These studies are expected to yield significant information regarding the interrelationship of these molecules and their association with normal cell surface molecules. Additionally, the receptor (Mr = 68 kilodaltons) for peanut agglutinin (PNA), previously shown in our laboratories to identify a population of high-risk null ALL patients, will similarly be investigated and compared by HPLC, peptide, and carbohydrate patterns with PNA receptors expressed on normal, neuraminidase-treated thymocytes (Mr = 70 kilodaltons). These studies will elucidate the nature of the leukemic PNA receptor as either a normal differentiation marker or a neoantigen associated with the transformed state. In addition, the 68 kilodalton PNA receptor and the gp100 from T-ALL will be isolated by affinity chromatography for use in the development of monoclonal antibodies. Efforts will continue toward the development of human and primate monoclonal antibodies directed toward leukemia-associated membrane determinants through fusion of B cells from immunized rhesus monkeys or remission leukemic individuals with human myeloma cell lines. Additional experiments will utilize mouse human hybrids in order to assign phenotypic expression of membrane markers to a particular chromosome. These experiments will establish a foundation for future investigations concerning molecular and genetic aberrations of human leukemic cells. (AG)
