An enzymatic assay for the detection of natural cytotoxicity

Diploid human lymphoblastoid and Burkitt lymphoma cell lines: susceptibility to murine NK cells and heterotransplantation to nude mice

Human lymphoid cell lines which had been classified on the basis of studies on clonality and morphological, on the basis of studies on clonality and morphological, chromosomal and functional parameters as lymphoblastoid cell line (LCL) of presumed non-neoplastic origin and Burkitt lymphoma (BL) lines of proven malignant origin, were tested for susceptibility to natural killer (NK) cells obtained from the spleens of athymic nude mice. The 20 lines included normal diploid LCL and aneuploid BL lines. All cells carried the Epstein-Barr virus (EBV) genome. In addition, two EBV-negative BL lines were tested. The pronase-induced release of 14C-DNA from 14C-thymidine-labelled target cells was used to assess the sensitivity of the cell lines to NK activity. When attempts were made to correlate the growth of the EBV-positive LCL and the EBV-positive BL cell lines in the subcutaneous space of adult nude mice with their susceptibility to NK cells, no significant correlation was observed. The EBV-negative BL cell line, Ramos, however, could be transplanted subcutaneously in nude mice and was more resistant to NK activity than was the EBV-negative BL cell line, BJAB, which cannot be transplanted subcutaneously. Growth of heterotransplanted EBV-converted cell lines in the subcutaneous space of adult nude mice may be influenced by immune effectors other than NK cells.