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 PREMATURE B- LYMPHOCYTES (PRE-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 PREMATURE B- LYMPHOCYTES (PRE-BC-GF). THE APPROACH WILL BE TO CONSTRUCT A CDNA LIBRARY FROM SIZED, ACTIVE, PRE-BC-GF MRNA AND TO ISOLATE A FULL-LENGTH PRE-BC-GF CDNA BY HYBRIDIZATION WITH AN OLIGONUCLEOTIDE PROBE DEDUCED FROM PROTEIN SEQUENCE INFORMATION DERIVED FROM PURIFIED PRE-BC-GF PROTEIN. DURING PHASE I, PRE-BC-GF ACTIVITY WILL BE PURIFIED FROM SUPERNATES PRODUCED BY A TRANSFECTED/TRANSFORMED MURINE STROMAL BONE MARROW CELL LINE (SV CELL LINE) RECENTLY DEVELOPED IN OUR LABORATORY. THE MRNA CODING FOR PRE-BC-GF ACTIVITY IN VITRO WILL ALSO BE PREPARED FROM THE SV CELL LINE AND SIZE FRACTIONATED IN PREPARATION FOR CDNA CLONING. ONCE MURING PRE-BC-GF CDNAS ARE ISOLATED, THEY WILL BE EXPRESSED IN APPROPRIATE YEAST AND E. COLI VECTORS. RECOMBINANT PRE-BC-GF WILL THEN BE TESTED FOR BIOLOGICAL ACTIVITY IN MURINE MODEL SYSTEMS OF B-CELL DEFICIENCY. FINALLY, MURINE CDNAS FOR PRE-BC-GF WILL BE USED AS PROBES FOR IDENTIFICATION BY SOUTHERN BLOT HYBRIDIZATION OF ANALOGOUS HUMAN CDNAS. PRE-BC-GF COULD BE OF VALUE IN CLINICAL RESTORATION OF ANTIBODY RESPONSIVENESS IN CASES OF VIRAL, CHEMOTHERAPEUTIC, OR RADIATION INDUCED IMMUNE SUPPRESSION.