Induction of immunologic tolerance to thymus-dependent antigen (sheep's red blood cells) in the absence of T cells

Abstract

The role of T cells in the induction of tolerance of B cells to sheep's red blood cells (SRBC) by means of cyclophosphamide (CP) was investigated. Tolerance was obtained in adult intact mice, in mice irradiated lethally and protected with syngeneic embryonic liver cells and thymocytes (TB mice), and in mice deprived of T cells—either thymectomized or lethally irradiated and protected with embryonic liver cells (B mice). This form of tolerance was shown to be due to specific elimination of T lymphocytes and, to some extent also, of B lymphocytes. Tolerogenic treatment of B mice, as also of TB mice, led to depression of their immunoreactivity. Spleen cells of tolerant B mice did not suppress the immune response of intact spleen cells. It is concluded that under the conditions investigated, tolerance of B cells can be formed without the participation of T lymphocytes.