Healthy elderly people lack neutrophil-mediated functional activity to type V group B Streptococcus

被引:11
作者
Amaya, RA
Baker, CJ
Keitel, WA
Edwards, MS
机构
[1] Baylor Coll Med, Dept Pediat, Infect Dis Sect, Houston, TX 77030 USA
[2] Baylor Coll Med, Dept Mol Virol & Microbiol, Infect Dis Sect, Houston, TX 77030 USA
关键词
group B Streptococcus; neutrophil; antibody; immunization;
D O I
10.1111/j.1532-5415.2004.52009.x
中图分类号
R592 [老年病学]; C [社会科学总论];
学科分类号
03 ; 0303 ; 100203 ;
摘要
OBJECTIVES: To determine the function of capsular polysaccharide (CPS)-specific immunoglobulin-G (IgG) and neutrophils from older adults in increasing ingestion and killing of type V group B Streptococcus (GBS). DESIGN: Cross-sectional study. SETTING: Outpatient clinic at Baylor College of Medicine. PARTICIPANTS: The subjects were 40 healthy, community-dwelling adults aged 65 and older from Houston, Texas. MEASUREMENTS: The serum level of type V GBS CPS-specific IgG was measured using an enzyme-linked immunosorbent assay. Functional activity was evaluated using an opsonophagocytosis assay. RESULTS: Sera from four subjects promoted efficient neutrophil-mediated phagocytosis and killing of type V GBS (mean log(10) reduction+/-standard deviation in colony-forming units (cfu)=1.51+/-0.39). Each had serum CPS-specific IgG concentrations exceeding 1 mug/mL. Sera from 36 subjects did not promote neutrophil-mediated functional activity (mean log(10) reduction in cfu=-0.09+/-0.06; P=.025). Only one of these 36 had a CPS-specific IgG concentration exceeding 1 mug/mL. When pooled sera from young adults given type V GBS conjugate vaccine was added at CPS-specific IgG concentrations of 4 mug/mL or 0.4 mug/mL, sera from all subjects promoted neutrophil-mediated killing of type V GBS. No impairment was evident in the neutrophil function of elderly subjects when it was compared with that of young adults. CONCLUSION: CPS-specific IgG and neutrophils from healthy older adults function to ingest and kill type V GBS, but these antibodies are not present in sufficient amounts in most individuals. Further studies should determine whether a type V GBS vaccine induces functionally active antibodies in older people.
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页码:46 / 50
页数:5
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