Paired specimens of serum from patients from whom Bacteroides fragilis had been isolated were tested by complement fixation against a crude B. fragilis antigen. A high titre or a rise in titre to B. fragilis was obtained in each of five patients with infection after abdominal surgery but in none of 11 patients with postpartum pyrexia nor in nine with vaginitis.

Antigenic relationships between 12 locally isolated bdellovibrios and 3 established reference strains (109D, 6-5-S, and UKi2) were investigated. Antigenicity of the strains was examined by use of the micro-complement fixation test, the serum and complement bactericidal test, and the immunodiffusion test. Antisera were prepared against one of the local strains (MS7) and against one of the establ...

It was shown that, on average, the titres of the sera obtained by both the anti-complement immunofluorescence (ACIF) and indirect immunofluorescence for viral late antigens (IFA-LA) procedures were approximately eight times higher than those obtained by complement fixation. There was no significant difference between the mean ACIF and IFA-LA titres, but the former method was preferred because i...