The knowledge that exists of the role of complement in immune reactions has been gained from investigations limited almost entirely to studies in vitro. Very little is known of the role of complement in immune reactions in vivo. I t has not been demonstrated that complement fixation occurs in animal tissues in vivo in some way analogous to the fixation of complement to antigen-antibody aggregat...

Cytomegalovirus antibodies were measured in human sera by a nuclear anticomplement immunofluorescence test that used as antigen the isolated nucleic of virus-infected fibroblasts cells lysed in distilled water. The method exhibited less nonspecific fluorescence than either a conventional whole-cell anticomplement immunofluorescence test or an indirect fluorescent antibody test applied to the sa...

Sheep and guinea pigs were immunized with cellular and extracellular antigen from Legionella pneumophila bacteria. After immunization, the animals developed immunoglobulin G titers against the immunizing agent. The same sera were also tested in a Mycoplasma pneumoniae complement fixation test. All the preimmunization sera from sheep showed positive M. pneumoniae complement fixation tests of var...