The effects of anti-CD3 antibodies on the development of T-cell receptor alpha beta + lymphocytes in embryonic thymus organ cultures.

Cells expressing the gamma delta T-cell receptor in association with CD3 molecules appear in the embryonic thymus before alpha beta CD3+ cells. We have added anti-CD3 antibodies to organ cultures of mouse thymus removed from embryos before any CD3+ cells have appeared, with the aim of blocking the function of the latter as they are generated in the cultures. Our results show that these antibodies affect the maturation of precursors of alpha beta + cells so that D-J but not V-D-J beta-chain arrangements predominate. In contrast, full length alpha gene transcripts are produced. These results are compatible with the view that the early population of gamma delta CD3+ cells plays a role in the maturation of the alpha beta + population.