Abstract
A large amount of thymic lymphocytes (tymocytes) obtained from thymuses of 2 to 3 young rabbits were injected intravenously into one adult rabbit in a form of cell suspension in physiological saline solution, and the behavior of the injected thymocytes was compared with that of the lymphocytes observed in the previous experiments (OSOGOE, 1944; 1950).
1. The chief findings which agreed in both the present and the previous experiments were: 1. From 48 to 72 hours after injection, there occurred a striking focal accumulation of lymphocytes, including large lymphocytes, in the periportal spaces of the liver and in the perifollicular regions of the spleen. 2. No remarkable lymphocytosis was produced by intravenous injections, except in one example which was represented in Table 1. These findings, especially the former, prove the physiological identity of thymocytes and lymphocytes.
2. The main difference between the present and the previous experiments was as follows: The lymphocyte accumulations in the periportal spaces of the liver, which had been produced by injection of thymocytes in the present experiments, disappeared within several days without showing any tendency towards growth, whereas those produced by injection of lymphocytes in the previous experiments persisted for a much longer period and often showed a tendency towards growth. Other differences of minor significance were also recognized.
3. The above-mentioned difference between the present and the previous experiments may be ascribed to the fact that the tymocytes are more susceptible to mechanical agitation than lymphocytes and easily injured by the procedure of making cell suspensions, and due by no means to the non-lymphocytic nature of thymocytes.
4. The blood picture of one example, in which a marked lymphocytosis (maximum 55, 000 lymphocytes per cubic millimeter) was produced immediately after the injection of thymocytes, was described (Table 1). This is of interest because no such information has hitherto been gained, so far as the authors are aware of.
