Purified EBV DNA and cloned DNA fragments were trapped in Sendai virus (SV) envelopes during envelope reconstitution. The DNA-loaded reconstituted envelopes (RSVE/DNA) served as gene-transfer vehicles using the capability of RSVE to fuse with normal and tumor cells. The efficiency of RSVE-mediated EBV DNA transfer into lymphoid tumor cells and fresh human lymphocytes was 5-10% of the enveloped 3H-labeled EcoRI fragment B of EBV DNA. Purified intracellular EBV (B95-8 strain) DNA induced EBV nuclear antigen (EBNA) in 0.2-1% of human lymphocytes, transiently stimulated cellular DNA synthesis, but did not fully transform cells. Cloned Sal I F1 fragment [approximately equal to 9 kilobase pairs (kbp)] and a smaller BamHI K (5.2 kbp) fragment from the same region of B95-8 EBV DNA induced EBNA in 2-4% of human lymphocytes but did not stimulate DNA synthesis nor transform cells. Cloned BamHI D1 fragment (approximately equal to 9 kbp) from AG-876 virus DNA, or a combination of cloned BamHI X and H fragments (approximately equal to 2 and 7 kbp, respectively) from the similar region of B95-8 virus DNA, significantly stimulated lymphocyte DNA synthesis, but EBNA could not be detected and transformation was not achieved. Early antigen and viral capsid antigen were not observed with any of the fragments tested. Our results suggest that the induction of EBNA and stimulation of lymphocyte proliferation are not controlled by the same region of EBV DNA.