Studies on the murine Ss protein: demonstration that the Ss protein is functionally the fourth component of complement

Proc Natl Acad Sci U S A. 1978 May;75(5):2424-8. doi: 10.1073/pnas.75.5.2424.


This report describes a simple and reproducible assay for the fourth component of murine complement (C4). Utilizing this assay, experiments are described which conclusively demonstrate that the murine Ss protein (serum substance) is functional C4 and that ascitic fluid may be used as a source for isolating Ss. The evidence that Ss is functional C4 is: (i) pretreatment of mouse plasma with F(ab')2 anti-Ss completely abrogated the C4 hemolytic titer; and (ii) in the isolation of the Ss protein from ascitic fluid, Ss immunochemical activity and C4 functional activity coeluted in each step of a four-step purification procedure.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antigen-Antibody Reactions
  • Ascitic Fluid / immunology
  • Blood Proteins / isolation & purification
  • Blood Proteins / metabolism*
  • Complement C4 / analysis
  • Complement C4 / isolation & purification
  • Complement C4 / metabolism*
  • Mice / immunology*


  • Blood Proteins
  • Complement C4