Functional characterization of human IgG, IgM, and IgA antibody directed to the capsule of Haemophilus influenzae type b. J Infect Dis 1986 Jan;153(1):8-16
Date
01/01/1986Pubmed ID
3484506DOI
10.1093/infdis/153.1.8Scopus ID
2-s2.0-0022629499 (requires institutional sign-in at Scopus site) 77 CitationsAbstract
Antibody to the capsular polysaccharide (CP) of Haemophilus influenzae b (Hib) is bactericidal, opsonic, and protective. Minimum protective levels of primarily IgG antibody to Hib CP, calculated from passive immunization studies, have been found to be approximately .06-.15 microgram/ml of serum. The human response to antigenic challenge with the Hib capsule, however, includes production of antibody to Hib CP of different isotypes whose function against Hib is unclear. In order to characterize the function of antibody to Hib CP of different isotypes, we purified human IgG, IgM, and IgA from the serum of an adult donor who had been previously immunized with purified Hib CP vaccine. The globulin preparations were greater than 99% isotypically pure, contained large quantities of anticapsular antibody, and differed in function against Hib. IgG antibody to Hib CP was bactericidal and opsonic for human polymorphonuclear leukocytes (PMNLs) in the presence of complement and protective in infant rats. IgM, although more bactericidal than IgG (P less than .01) and equally protective in rats, opsonized Hib poorly for PMNLs. IgA was not bactericidal or opsonic and did not prevent bacteremia and meningitis in rats challenged with Hib. We conclude that antibody directed against the capsule of Hib differs in antibacterial function depending on class. These data may be important to acurately estimate minimum protective levels of anticapsular antibody after vaccination or natural infection and may have implications for the manner in which the host clears Hib from the circulation.
Author List
Schreiber JR, Barrus V, Cates KL, Siber GRMESH terms used to index this publication - Major topics in bold
AnimalsAntibodies, Bacterial
Antibody Affinity
Blood Bactericidal Activity
Haemophilus Infections
Haemophilus influenzae
Humans
Immunization, Passive
Immunoglobulin A
Immunoglobulin G
Immunoglobulin M
Opsonin Proteins
Polysaccharides, Bacterial
Rats