Comparative effects of protracted protein deprivation on the DNA synthetic and mitogenic actions of phytohemagglutinin and concanavalin A in vivo on the lymphocytes of the rat.

The increase rate of DNA synthesis and mitotic activity in popliteal lymph nodes following subplantar injection of PHA was significantly reduced in rats subjected to a protein-free diet given for 9 weeks. On the contrary, the lymph node responses to Con A were higher with latter diet than with a balanced 18% casein diet. On the other hand, PHA reduced the weight and proliferative activity of the thymus, and probably also increased the emigration of thymocytes in protein deprived rats, while Con A was devoid of any effects. Thus, mainly the activity of the PHA-responsive subset of T lymphocytes and thymocytes appeared to be disturbed after protein deprivation. According to previous work, this subset was formed of high theta, cortisone-sensitive celles.