properdin system

pro·per·din sys·tem

an immunologic system that is the alternative pathway for complement, composed of several distinct proteins that react in a serial manner and activate C3 (third component of complement), seemingly without using components C1, C4, and C2; in addition to properdin, the system includes Factors B, D, H, and I. The system can be activated, in the absence of specific antibody, by bacterial endotoxins, by a variety of polysaccharides and lipopolysaccharides, and by a component of cobra venom.

pro·per·din system

(prō'pĕr-din sis'tĕm)
An immunologic system that is the alternative pathway for complement, composed of several distinct proteins that react in a serial manner and activate C3 (third component of complement); the system can be activated, in the absence of specific antibody, by bacterial endotoxins, and a variety of polysaccharides and lipopolysaccharides.