1. Naturally Acquired Antibodies against Haemophilus influenzae Type a in Aboriginal Adults, Canada
- Author
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Daniel S. Schmidt, Marina Ulanova, Eli B. Nix, Kylie Williams, Andrew D. Cox, Sandra Romero-Steiner, Frank St. Michael, and William McCready
- Subjects
Male ,Epidemiology ,Igm antibody ,lcsh:Medicine ,Disease ,0302 clinical medicine ,Antibody Specificity ,vaccine ,Antibody activity ,030212 general & internal medicine ,indigenous ,bacteria ,Aboriginal ,polysaccharide antibodies ,Aged, 80 and over ,0303 health sciences ,Haemophilus influenzae type a ,Invasive disease ,Polysaccharides, Bacterial ,Middle Aged ,Antibodies, Bacterial ,3. Good health ,Titer ,Infectious Diseases ,Female ,Antibody ,Adult ,Microbiology (medical) ,Canada ,Haemophilus Infections ,IgM ,IgG ,Bactericidal antibody ,Biology ,Microbiology ,lcsh:Infectious and parasitic diseases ,Young Adult ,03 medical and health sciences ,Hia ,bactericidal ,Humans ,lcsh:RC109-216 ,Naturally Acquired Antibodies against Haemophilus influenzae Type a in Aboriginal Adults, Canada ,Aged ,030304 developmental biology ,Antigens, Bacterial ,antibody functional activity ,Research ,lcsh:R ,Complement System Proteins ,biochemical phenomena, metabolism, and nutrition ,Haemophilus influenzae ,Aborigine ,Immunoglobulin M ,Immunoglobulin G ,North America ,Immunology ,biology.protein ,secondary immunodeficiency - Abstract
High prevalence of invasive Hia disease among North American Aboriginal populations is more likely related to exposure than to inadequate immunity., In the post-Haemophilus influenzae type b (Hib) vaccine era that began in the 1980's, H. influenzae type a (Hia) emerged as a prominent cause of invasive disease in North American Aboriginal populations. To test whether a lack of naturally acquired antibodies may underlie increased rates of invasive Hia disease, we compared serum bactericidal activity against Hia and Hib and IgG and IgM against capsular polysaccharide between Canadian Aboriginal and non-Aboriginal healthy and immunocompromised adults. Both healthy and immunocompromised Aboriginal adults exhibited significantly higher bactericidal antibody titers against Hia than did non-Aboriginal adults (p = 0.042 and 0.045 respectively), with no difference in functional antibody activity against Hib. IgM concentrations against Hia were higher than IgG in most study groups; the inverse was true for antibody concentrations against Hib. Our results indicate that Aboriginal adults possess substantial serum bactericidal activity against Hia that is mostly due to IgM antibodies. The presence of sustained IgM against Hia suggests recent Hia exposure.
- Published
- 2015