[A study on the veto cells from H-2 recombinant mice and allogeneic bone marrow chimeric mice]

Veto cells are unique suppressor cells which inhibit the generation of cytotoxic T lymphocyte (CTL) responses directed against the target cells sharing the same class I (H-2) antigens with them. These cells have been considered to be involved in establishing self-tolerance by deleting cells that retain self reactivity at a pre-thymic stage of development. However, any concreate evidences for the postulate have not yet been reported. In the present study, the author analyzed the H-2 specificity of the CTL inhibition induced by veto cells and characterized the property of the cells in bone marrow. When added to a mixed lymphocyte culture (MLC), bone marrow cells, syngeneic to the stimulator of the MLC, suppressed the development of CTLs against themselves. Furthermore, from experiments in which bone marrow cells from B10 H-2 recombinant mice were employed as the veto cell source, it was demonstrated that the suppression was induced by cells sharing the H-2 class I antigens with the stimulator. The cells exhibiting the veto activity were radiation sensitive and Sephadex G-10 non-adherent. They were also Thy-1-, Ly-1-, Ly-2- and sIg- and thus were thought to belong to non-T and non-B cells. To study the functional role of the veto cells in establishing self tolerance to H-2 class I antigens, next we analyzed the inhibitory specificities of the veto cells in bone marrow obtained from fully allogeneic bone marrow chimeras. Veto cells from such chimeras suppressed the generation of CTL responses against not only donor (self) type but also recipient type.(ABSTRACT TRUNCATED AT 250 WORDS)