Complement components required for virus neutralization by early immunoglobulin antibody

Proc Natl Acad Sci U S A. 1969 Oct;64(2):520-7. doi: 10.1073/pnas.64.2.520.


Virus neutralization by early antisera usually requires or is enhanced by the presence of complement. The particular components of the complement system which are needed for neutralization of Newcastle disease virus by early IgM antibodies were studied. It was found in this system that participation of only the first four of the nine complement components (C1, C2, C3, and C4) was necessary and sufficient for neutralization to occur. It was concluded that the role of complement in neutralization was most likely that of contributing bulk in the form of large protein molecules to the virus-antibody complex.

MeSH terms

  • Animals
  • Antigen-Antibody Reactions
  • Complement System Proteins / pharmacology*
  • Edetic Acid
  • Guinea Pigs
  • Immunoglobulin M*
  • Neutralization Tests*
  • Newcastle disease virus / immunology*
  • Rabbits


  • Immunoglobulin M
  • Complement System Proteins
  • Edetic Acid