THE LONG-TERM OBJECTIVE OF THIS PROJECT IS THE MOLECULAR CHARACTERIZATION (CDNA CLONING, EXPRESSION) OF MURINE AND HUMAN GENES CODING FOR A GROWTH FACTOR FOR MATURE B- LYMPHOCYTES (M-BC-GF).

THE LONG-TERM OBJECTIVE OF THIS PROJECT IS THE MOLECULAR CHARACTERIZATION (CDNA CLONING, EXPRESSION) OF MURINE AND HUMAN GENES CODING FOR A GROWTH FACTOR FOR MATURE B- LYMPHOCYTES (M-BC-GF). OUR APPROACH WILL BE TO CONSTRUCT A CDNA LIBRARY FROM SIZED, ACTIVE, M-BC-GF MRNA AND TO ISOLATEA FULL-LENGTH M-BD-GF CDNA BY HYBRIDIZATION WITH AN OLIGONUCLEOTIDE PROBE DEDUCED FROM PROTEIN SEQUENCE INFORMATION DERIVED FROM PURIFIED M-BC-GF PROTEIN. DURING PHASE I, M-BC-GF ACTIVITY WILL BE PURIFIED FROM SUPERNATES PRODUCED BY A CLONED MURINE LYMPHOMA CELL LINE (EL-4 LX CELLLINE) RECENTLY DEVELOPED IN OUR LABORATORY. MRNA CODING FORM-BC-GF ACTIVITY IN VITRO WILL ALSO BE PREPARED FROM THE EL-4 LX CELL LINE AND SIZE FRACTIONATED IN PREPARATION FOR CDNA CLONING. ONCE MURINE M-BC-GF CDNAS ARE ISOLATED, THEY WILL BE EXPRESSED IN APPROPRIATE YEAST AND E. COLI VECTORS. RECOMBINANT M-BC-GF WILL THEN BE TESTED FOR BIOLOGICAL ACTIVITY IN MURINE MODEL SYSTEMS OF B-CELL DEFICIENCY. FINALLY, MURINE CDNAS FOR M-BC-GF WILL BE USED AS PROBES FORIDENTIFICATION BY SOUTHERN BLOT HYBRIDIZATION OF ANALOGOUS HUMAN CDNAS. M-BC-GF COULD BE OF VALUE IN CLINICAL RESTORATION OF ANTIBODY RESPONSIVENESS IN CASES OF VIRAL, CHEMOTHERAPEUTIC, OR RADIATION INDUCED IMMUNE SUPPRESSION, AND FOR THE IN VITRO GENERATION OF HUMAN B-LYMPHOCYTES AND/ OR HYBRIDOMAS.