Activation of DNA metabolism in T-cells by bestatin

Bestatin, [(2S, 3R)-3- amino-2- hydroxy-4- phenylbutanoyl]- l- leucine , is a microbial product which selectively influences the DNA metabolism of lymphoid tissues in vivo. The present studies, using CBA/J mice, revealed that bestatin increases the incorporation rate of dThd into DNA in spleen, thymus and bone marrow, but not in liver, kidney, spinal cord and lung. The stimulation was found to be dose-and timedependent, and it occurs only in T-cells, not in B-cells, from spleen and thymus. In addition, it is shown that bestatin causes a several-fold induction of DNA polymerase α only in T-cells from spleen and thymus, while the level in B-cells remains constant. Bone marrow cells respond to bestatin treatment with an increase of the DNA polymerase α activity and with an 8-fold induction of terminal deoxynucleotidyl transferase.