[Production of secondary T-killers]

Restimulation of lymphocytes on the 8th day of mixed lymphocyte culture (MLC) and cultivation on the monolayer of syngeneic macrophages are accompanied by an increase in the DNA synthesis, which rises negligibly within the first 24 hours, reaches maximum after 48 hours and then drops. After reexposition with alloantigen lytic activity of lymphocytes reaches the level of initial culture within the first 24 hours and in the 48-72 hours following increases 2-4-fold. On the 11th-12th days of MLC secondary T-killers transform to medium-size and small lymphocytes whose cytoplasm shows the signs of activation of the secretory apparatus on interaction with target-cells. It is assumed that secondary antigenic stimulus in vitro induces the differentiation of T-killers that correspond with immune lymphocytes isolated after immunization in vivo.