As shown on the model of spontaneous apoptosis of leukocytes from periphera
l blood of donors, thymodepressin and neogen have similar action. Low doses
of the drugs reduce the ability of granulocytes and lymphocytes for sponta
neous apoptosis while high doses stimulate apoptosis of these cells. The ef
fects realize after 1-hour incubation of cells with thymic peptides. Possib
le mechanisms of such effects are discussed.