KGF treatment and androgen blockadebeforeBMT enhance the secondary humoral immune response to KLH after allogeneic BMT. Lethally irradiated C57BL/6 recipients of allogeneic (BALB/c) bone marrow were left untreated (BMT Control) or pretreated with KGF, leuprolide acetate, or KGF + leuprolide acetate and immunized at day 28 after BMT with 50 μg of KLH in Complete Freund's adjuvant (KLH/CFA) alongside unmanipulated age/sex-matched C57BL/6 control animals (non-BMT Control). Two weeks after primary immunization (equivalent to day 42 after BMT), mice were rechallenged with 50 μg of KLH in Incomplete Freund's adjuvant (KLH/IFA). Serum was then collected after 7 days and analyzed with the use of ELISA for total IgG1 (A) and KLH-specific IgG1 (B) antibody levels. Data shown are mean micrograms of IgG1 per milliliter of serum (± SEM) from one experiment with 4 mice per group; *P < .05 compared with untreated BMT control mice.