c-kit expression by B cell precursors in mouse bone marrow. Stimulation of B cell genesis by in vivo treatment with anti-c-kit antibody.

To examine the in vivo role of c-kit receptor in B lymphopoiesis we have evaluated precursor B cell populations expressing c-kit in mouse bone marrow and the effects on B cell genesis of administering a neutralizing anti-c-kit mAb, ACK2. Double immunofluorescence labeling and mitotic arrest were used to examine bone marrow cells from BALB/c mice. Almost one-half of TdT+ cells and one-quarter of B220+ cells coexpressed c-kit, mainly at low intensities, and were actively proliferating in vivo.