Studies on rabbit hyperimmune, patient and blood donor serum with regard to bactericidal activity and serum antibodies against anaerobic curved rods from patients with bacterial vaginosis.

Serum specimens from patients with bacterial vaginosis (BV) from whom anaerobic curved rods (ACR) were isolated, from healthy female and male blood donors and from rabbits immunized with ACR were tested for anti-ACR antibodies by indirect immunofluorescence and for bactericidal activity. The rabbit sera had antibody titres ranging from 1 : 160 to 1 : 2560 but no bactericidal activity could be demonstrated. Very low titres (1:10) of IgM antibodies were detected in serum from a few patients as well as from a few female and male blood donors, whereas no IgG or IgA antibody titres (less than 1:10) were demonstrated. No bactericidal activity was found in the human sera against ACR. We conclude that no systemic antibody response can be demonstrated in patients with BV from whom such organisms are isolated. Moreover, these organisms behave differently from other Gram-negative bacterial species, in that they are resistant to normal serum as well as the specific antibody-complement-mediated bactericidal activity.