Abstract
Effects of the humoral factor extracted from the calf thymus (thymosin: Goldstein et al. ) and the supernatant of cultured mouse thymus reticuloepithelial cell (TRC) on immunological functions of the mouse lymphocytes were studied, and the following conclusions were drawn: Thymosin treatment did not alter the capacity to form anti-SRBC antibody in adult mice which were lethally irradiated and reconstituted with bone marrow cells. When the spleen cells from JCL-ICR mice thymectomized within 24 hr after birth were cultured with thymosin or supernatant of cultured ICR-TRC, the Thy 1 positive cells were increased. A significant increase in the mitogenic (PHA, Con A) reactivity of BALB/C spleen cells was observed when these cells were preincubated in medium containing thymosin for 24 hr. The NZB spleen cells, however, exhibited no potentiated responses even when precultured with thymosin, and the nu/nu spleen cells showed a slightly potentiated response only to Con A. Similarly, thymosin enhanced the MLC reaction of the spleen cells from BALB/C mice with preincubation for 2 hr, but not enhanced that from NZB mice.
