ABSTRACT

This chapter summarizes the data that strongly implicate a role for soluble mediators in general and lymphotoxin, in particular, in cytotoxic T lymphocyte (CTL) killing. Lymphotoxin plays an important role in cytolytic T cell killing. The extent of this role and the relationship of lymphotoxin to other described cytolytic mediators remains unclear. Lymphotoxin is assayed by its ability to inhibit the growth of a target cell in tissue culture. The development and analysis of clonally derived cell lines such as IL-2 maintained T cell clones, T cell hybridomas, and lymphomas has allowed production of large quantities of lymphokines from the progeny of a single cell. Several arguments have been advanced that purport to exclude a role of lymphotoxin (LT) in CTL killing. The descriptions of LT had suggested that there were several different classes of LT distinguishable by size and reactivity with various antibodies.