The role of interleukin-4 in the regulation of mouse primordial germ cell numbers.

Interleukin-4 (IL-4), a pleiotropic cytokine, stimulates a dose-dependent increase in the number of mouse primordial germ cells in culture. Results from bromodeoxyuridine incorporation assays suggest that IL-4 acts as a survival factor rather than as a mitogen for primordial germ cells in this system. Studies on the embryonic expression patterns of IL-4 and its receptors, using RT-PCR and ELISA, show that IL-4 and its receptors are present at the correct time and place to influence PGC numbers in vivo.