[Bactericidal antibody micro-assay for detection of antibodies against meningococci (author's transl)]

The best way to detect protective antibodies against meningococci in human serum seems to prove its bactericidal activity. For this a bactericidal antibody assay was described by WHO. For this test, however, a high amount of baby rabbit-serum is required. Therefore a modification was introduced by reducing the test volumes, performing the test in microtiterplates and using TTC (triphenyl tetracolium chloride), as a growth indicator that changes from colourless to purple red in the presence of growing meningococci. The end point of serum titration is the last well containing colourless medium.