Separation of cytotoxic lymphocytes against Marek's disease lymphoblastoid cell lines on Percoll gradients

A two-step method has been developed for the separation of lymphocytes cytotoxic for allogeneic Marek's disease lymphoblastoid cell lines. Ficoll-Paque-purified spleen cell suspensions were separated according to their densities on continuous gradients of Percoll. Pooled fractions were tested for specific release in a 4-hour chromium release assay. Cytotoxic activity was mainly detected in the fractions with a density of 1.060 to 1.070 g/ml. Levels of specific release were increased using those fractions compared to Ficoll-Paque-purified cells. A discontinuous Percoll gradient was developed based on the density range of cytotoxic cells. Continuous and discontinuous Percoll gradients were equally effective for the preparation of cytotoxic cells.