Human IgG and IgA subclass response following immunization with a polyvalent Klebsiella capsular polysaccharide vaccine.

The human IgG and IgA response was determined after vaccination with an experimental 24-valent Klebsiella capsular polysaccharide vaccine. The majority of natural antibody acquired prior to immunization was found in the IgG1, IgG2 and IgA1 subclasses. The immune response to vaccination was concentrated within the IgG1, IgG2, IgA1 and IgA2 subclasses with greater than or equal to 70% of subjects responding with a significant (greater than or equal to fourfold) rise in titer. The IgG3 and IgG4 response was meager with few volunteers (0%-40%) showing a significant titer rise. Therefore, vaccination with Klebsiella capsular polysaccharide induces a vigorous IgG and IgA response in humans which is not restricted to single antibody class or subclass.