Lower antibody functionality in middle-aged adults compared to adolescents after primary meningococcal vaccination: Role of IgM.
INTRODUCTION
Successful vaccination of elderly persons is often hampered by immunological ageing, leaving part of the elderly population vulnerable for infectious diseases. As an alternative, timely vaccinations might be administered at middle-age, before reaching old age. Studies evaluating the immunological fitness of middle-aged adults are warranted. In this study we compared the immunogenicity of a primary meningococcal vaccination in Dutch middle-aged adults with that in adolescents, in order to gain knowledge on the early signs of immune ageing.


METHODS
In this study, we compared the antibody responses after a primary meningococcal vaccination between middle-aged adults (50-65years of age, N=204) and adolescents (10-15years of age, N=225). Blood samples were taken pre-, as well as 28days and 1year post-vaccination. Functional antibody titers were measured with the serum bactericidal killing assay using baby rabbit complement (rSBA). Meningococcal polysaccharide (PS) specific IgG and IgM concentrations were determined with a fluorescent bead-based multiplex immunoassay.


RESULTS
Lower post-vaccination functional antibody titers against meningococcal group W and Y were observed in the middle-aged adults compared to the adolescents. One year post-vaccination, also a significantly higher proportion of the middle-aged adults possessed an rSBA titer below protection level. A large reduction in post-vaccination IgM concentrations was observed in the middle-aged adults, whereas IgG concentrations were only marginally different between the two age groups. Strong correlations between the post-vaccination rSBA titers and IgM concentrations were found both in the middle-aged adults and the adolescents.


CONCLUSION
Although protective antibody titers were initiated after primary meningococcal vaccination in middle-aged adults, antibody functionality was significantly lower as compared to that in adolescents. This difference was mainly caused by lower IgM responses. Our results indicate early signs of immune ageing in middle-aged adults, which is important knowledge for the development of future vaccine strategies to better protect elderly persons against infectious diseases.
['van der Heiden|Marieke|M|', 'van Ravenhorst|Mariette B|MB|', 'Bogaard|Marjan|M|', 'Boots|Annemieke M H|AMH|', 'Berbers|Guy A M|GAM|', 'Buisman|Anne-Marie|AM|']
D000293:Adolescent D000368:Aged D000375:Aging D000907:Antibodies, Bacterial D005260:Female D006801:Humans D000071497:Immunogenicity, Vaccine D007074:Immunoglobulin G D007075:Immunoglobulin M D016014:Linear Models D008297:Male D008585:Meningitis, Meningococcal D022401:Meningococcal Vaccines D008875:Middle Aged D015610:Serum Bactericidal Test D013997:Time Factors
Middle-aged adults Adolescents IgM MenACWY Primary vaccination