ABSTRACT
This chapter presents various lines of evidence that support each component of the proposed model and discusses the mechanism of killing by Natural Killer Cytotoxic Factor (NKCF) and potential diagnostic and therapeutic implications of the NKCF system. Production of NKCF has been accomplished by both human peripheral blood and by rodent spleen cells. Coculture of natural killer (NK) cells with stimulator cells results in the release of maximal levels of NKCF activity in the culture supernatant. The chapter provides evidence that the subpopulation enriched in NK cells is responsible for secretion of NKCF. It proposes that NKCF binds to target cells through NKCF binding sites, and subsequently lysis takes place. The binding of NKCF to target cells is rapid and dependent on temperature and pH. The chapter investigates whether target resistance to NK cells is a property of the membrane. NKCF-containing large unilamellar vesicles were prepared and incubated with various NK-resistant and sensitive target cells.
