Daudi Burkitt's lymphoma cells have molecules on their surface which can stimulate proliferation of human gamma delta T cells, while Raji, another Burkitt's lymphoma, cannot stimulate human gamma delta T cells. Human peripheral gamma delta T cells, coexpressing the V gamma 9/V delta 2 chains of the T cell receptor, lyse Daudi cells but not Raji cells. Here, we have screened four other Burkitt's lymphoma cell lines (HH514, DG75, Ramos, and Wilson), as well as cells derived from a fresh Burkitt's lymphoma, to see if any of them can be recognized by human gamma delta T cells. Leukemia-derived lines MOLT-4, CEM, and K562 have also been included in these studies. Among the Burkitt's lymphomas tested, only Daudi, DG75, and HH514 could be lysed by V gamma 9/V delta 2+ T cell clones derived from the peripheral blood of healthy donors. These T cell clones were also able to lyse the NK sensitive leukemia lines K562 and MOLT-4. When bulk cultures of peripheral blood mononuclear cells from healthy donors were cultured with different Burkitt's lymphoma or leukemia cell lines, only Daudi stimulated the outgrowth of gamma delta T cells. Similarly, only Daudi cells could stimulate proliferation of gamma delta T cell clones, and the response was enhanced significantly in the presence of interleukin-2. These data and our prior observations showing the use of the V gamma 9/V delta 2 TCR type by Daudi-reactive human gamma delta T cells indicate that Daudi cells are not representative of other Burkitt's lymphoma cell lines.