MHC restriction of murine T lymphocyte reactivity analysed by growth of bone marrow cells in vitro on thymus epithelial monolayers.

Mature mouse T lymphocytes, derived from long-term culture of bone marrow cells on thymus epithelial monolayers, were analysed with respect to their ability to co-operate with B cells (for antibody production) or T cells (in the generation of cytotoxic cells) when the bone marrow T precursor cells and the thymus epithelial cells differ at defined regions of the major histocompatibility complex. A pool of more mature bone marrow T-cell precursors gave rise to T cells interacting only with T/B lymphocytes sharing MHC determinants with the strain of origin of the bone marrow cells used. In contrast, a more immature bone marrow T-cell precursor pool produced T lymphocytes which had acquired MHC restriction (in terms of co-operativity with T/B cells) as defined by the MHC determinants of the thymus epithelium, and not those MHC determinants of the cultured bone marrow population. In addition, some evidence was obtained for Ir gene control (mapping in the MHC region) in the development of the repertoire of T cells involved in production of cytotoxic responses in vitro to TNP-modified self antigens.