Contribution of Serum and Cellular Factors in Host Defense Reactions

Abstract

THE principal noncellular factors definitely involved in host resistance are complement and antibody. Although a specific immune antibody response may be too delayed to protect the immunologically inexperienced host against an overwhelming infection the so-called natural antibodies can contribute to innate or nonspecific resistance. Whether complement and these natural antibodies, which in all likelihood arise as a result of specific or crossreacting subclinical antigenic stimulation, account for all the actions attributed to the properdin system is a matter of much concern and is discussed below.The role of antibody (natural or immune) and complement in mediating serum bactericidal activity against . . .