Kinetic analysis of human spontaneous cell-mediated cytotoxicity
Pollack, S.B.; Emmons, S.L.
Journal of Immunology 123(1): 160-165
1979
ISSN/ISBN: 0022-1767 PMID: 448145 Document Number: 140841
Whether the kinetics of human spontaneous cell-mediated cytotoxicity (SCMC) fit the enzyme-substrate model for cellular cytotoxicity was tested. As predicated by the model, the maximal rate of killing (Vmax) was proportional to the number of effector cells added; the apparent affinity constant K1/2 was a function of the source of effector cells and remained unchanged when the number of effector cells was doubled. The linear initial velocity of lysis was maintained for only 90 min; thereafter, lysis proceeded at a lower rate. The model strictly applied only during the initial phase. Two lines of evidence suggested that NK on NK cells are implicated as the active site for SCMS or as closely linked to the active site.