Spontaneous Cell‐mediated Cytotoxicity (SCMC) in Various Mammalian Species and Chickens: Selective Reaction Pattern and Different Mechanisms

Abstract

Cultured cell lines derived from donors of various species as ⁷⁵Se- or ⁵¹Cr-labelled targets in microcytotoxicity assays. As in human donors, considerable spontaneous cell-mediated cytotoxicity (SCMC) was exhibited by peripheral blood lymphoid effector cells from healthy chickens, mink, swine, cattle, horses and tigers. Although all target lines tested could be lysed in SCMC, there was no ‘general SCMC target’ for all species of all individuals of one species. The selectivity, the kinetics, and the strength of SCMC reflected the capacity of the effector cells rather than a ‘susceptibility’ of the target to lysis. Classical major histocompatibility complex products, determinants specific for distinct cell types or subpopulations, or antigens associated with Epstein-Barr virus, herpes virus ateles, herpes virus papio, or Marek's disease virus were not appreciably involved in SCMC. No ‘malignant phenotype’ on targets was required for the cytotoxic effect. Yet undefined xenogenic, allogenic, and individual structures seem to be involved in SCMC. Depending on their expression, a target can he classified as ‘species related’ or as ‘individual-related’. Intermediate forms are conceivable. SCMC might comprise different cytotoxic mechanisms. Antibodies are not required for lysis to occur, but serum factors including immunoglobulins can have considerable influence on SCMC.