ABSTRACT
Objective To analyze the structures and molecular weight distributions of the capsular polysaccharides from 6 serotypes of pneumococcus .Methods The structures of pneumococcal capsular pol-ysaccharides of 6 serotypes were analyzed by 1 H nuclear magnetic resonance ( NMR) .Chemical shifts of all characteristic protons were investigated to analyze polysaccharide integrity and inter -assay consistency .High performance size exclusion chromatography-multi angle laser light scattering ( HPSEC-MALLS) was used to measure the molecular weights .Results The chemical shifts of all characteristic protons of the pneumococ-cal capsular polysaccharides of 6 serotypes were consistent with the standard chemical shift .The weight-aver-age molecular mass of the pneumococcal capsular polysaccharides ranged from 7.182×104 g/mol(for serotype 19A) to 1.273×106 g/mol(for serotype 9V)examined by HPSEC-MALLS.Conclusion The structures and molecular weight distributions of pneumococcal capsular polysaccharides could be rapidly and effectively ana -lyzed by 1 H NMR and HPSEC-MALLS.Moreover, C-PS and acetate contained in capsular polysaccharides could also be detected .HPSEC-MALLS is an applicable method for the quantitative analysis of molar mass distributions in different serotypes of pneumococcal capsular polysaccharides . Although 1 H NMR and HPSEC-MALLS have been accepted as the quality control measurements by WHO , to use them as the re-placements of the traditional QC method still needs further investigation .
ABSTRACT
Objectives To explore the humoral immunologic mechanisms of the susceptibility to invasive pneumococcal diseases (IPD) in asthmatic children. Methods Plasma samples were collected from 43 asthmatic and 20 non-asthmatic chil-dren. Anit-pneumococcal capsular polysaccharide (PPS)-IgG concentrations were measured by enzyme-linked immunosorbent assays. Results The mean concentrations of anti-PPS 14, 19A and 23F-IgG were signiifcantly higher in asthmatic children than in non-asthmatic children (P<0.05). The ratios of the asthmatic children who had anti-PPS 14, 19A and 23F-IgG concentrations higher than the protective antibody level (≥0.2 μg/ml ) were 100%for all the serotypes. Conclusions The immune responses of producing anti-PPS IgG to defense IPD were normal in asthmatic children. Asthmatic children may be more susceptive to pneumococcal infection or colonization than non-asthmatic children.