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. 1969 Aug;63(4):1151-6.
doi: 10.1073/pnas.63.4.1151.

Natural immunity to bacterial infections: the relation of complement to heat-labile opsonins

M R Smith, H S Shin, W B Wood Jr

Natural immunity to bacterial infections: the relation of complement to heat-labile opsonins

M R Smith et al. Proc Natl Acad Sci U S A. 1969 Aug.

Abstract

Heat-labile opsonins to pneumococci in normal mammalian sera, unlike antibodies, fail to interact with the bacteria at 0 degrees C and require Ca(++) and/or Mg(++). They are readily removed from serum by antigen-antibody complexes that fix complement (C) and are inhibited by reagents that inactivate various C components. The principal heat-labile opsonin to pneumococci is activated C3 (C3(b)), but a slight enhancing effect is exerted by one or more of the late-reacting components of the hemolytic complement system (C5-C9). Since heat-labile opsonins are immunologically polyspecific, they presumably play a broad protective role in the early (preantibody) phase of acute bacterial infections.

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References

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