Antibodies to Bordetella pertussis in human colostrum and their protective activity against aerosol infection of mice.

Colostrum samples from Indonesian mothers were assayed for antibodies which agglutinate Bordetella pertussis and for antibodies to the filamentous hemagglutinin and the lymphocytosis-promoting factor of B. pertussis. Agglutinins were assayed by a microtiter method, and 36 of 58 samples tested (62%) had titers above 1:10 (range, less than 1:10 to 1:160). An enzyme-linked immunosorbent assay detected anti-filamentous hemagglutinin in 39 of 60 samples (65%) and anti-lymphocytosis-promoting factor in 26 of 60 samples assayed (43%). A total of 52 samples (87%) were positive for at least one of these antibodies. Pooled colostrum samples were separated by affinity chromatography into fractions enriched secretory immunoglobulin A (sIgA) or IgG and examined for their ability to passively protect suckling mice from aerosol challenge with B. pertussis. Samples (160 micrograms of protein) were given intraperitoneally 90 min before challenge. Death, rate of gain in body weight, and leukocytosis were used as indicators of illness. Colostrum containing anti-lymphocytosis-promoting factor or agglutinins was protective, whereas colostrum lacking these but containing anti-filamentous hemagglutinin gave little protection. The sIgA-enriched and IgG-enriched fractions appeared to be equal in their ability to protect against respiratory challenge with B. pertussis.