V(H)3 antibody response to immunization with pneumococcal polysaccharide vaccine in middle-aged and elderly persons.
ABSTRACT Pneumococcal disease continues to cause substantial morbidity and mortality among the elderly. Older adults may have high levels of anticapsular antibody after vaccination, but their antibodies show decreased functional activity. In addition, the protective effect of the pneumococcal polysaccharide vaccine (PPV) seems to cease as early as 3 to 5 years postvaccination. Recently, it was suggested that PPV elicits human antibodies that use predominantly V(H)3 gene segments and induce a repertoire shift with increased V(H)3 expression in peripheral B cells. Here we compared V(H)3-idiotypic antibody responses in middle-aged and elderly subjects receiving PPV as initial immunization or revaccination. We studied pre- and postvaccination sera from 36 (18 vaccine-naïve and 18 previously immunized subjects) middle-aged and 40 (22 vaccine-naïve and 18 previously immunized subjects) elderly adults who received 23-valent PPV. Concentrations of IgGs to four individual serotypes (6B, 14, 19F, and 23F) and of V(H)3-idiotypic antibodies (detected by the monoclonal antibody D12) to the whole pneumococcal vaccine were determined by enzyme-linked immunosorbent assay (ELISA). PPV elicited significant IgG and V(H)3-idiotypic antibody responses in middle-aged and elderly subjects, regardless of whether they were vaccine naïve or undergoing revaccination. Age did not influence the magnitude of the antibody responses, as evidenced by similar postvaccination IgG and V(H)3 antibody levels in both groups, even after stratifying by prior vaccine status. Furthermore, we found similar proportions (around 50%) of elderly and middle-aged subjects experiencing 2-fold increases in V(H)3 antibody titers after vaccination. Age or repeated immunization does not appear to affect the V(H)3-idiotypic immunogenicity of PPV among middle-aged and elderly adults.
Full-textDOI: · Available from: Roger D Rossen, May 29, 2015
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ABSTRACT: Outer membrane protein antigens usually have strong immunogenicities, closely interact with the immune system and play a significant role in the development of new vaccines. The outer membrane proteins of Salmonella paratyphi A (S. paratyphi A) were screened for immunogenicity and immunoprotection for potential vaccine targets. In this study, the bactericidal effect of antiserum against the total outer membrane proteins of S. paratyphi A CMCC 50973 strain was determined, and their immunoprotection was detected with a challenge experiment on vaccinated mice. The immunogenic outer membrane proteins were identified via immunoproteomic technology, and recombinant outer membrane proteins were expressed and purified. The immunoprotection provided by the immunogenic membrane proteins was verified through active and passive immunity challenge experiments. The result revealed a number of S. paratyphi A outer membrane proteins that were proven as strong protective antigens. Twelve immunogenic outer membrane proteins were located and identified. Five recombinant proteins (LamB, pagC, TolC, nmpC and fadL) with strong immunoprotective abilities were found via the active immunity challenge experiment, with protection rates of 95, 95, 85, 80 and 70%, respectively. They were also proven to induce good immunoprotection via the passive immunity challenge experiment, with protection rates of 65, 55, 60, 55 and 50%, respectively. The immunoprotective rate of the five-antiserum combination was 85%. In conclusion, the LamB, pagC, TolC, nmpC and fadL outer membrane proteins, with strong immunogenicities and immunoprotection, are effective protein candidate targets for the development of new vaccines, whereas the recombinant outer membrane proteins are a promising tool for improving immunoprotection.Molecular Medicine Reports 09/2011; 5(1):78-83. DOI:10.3892/mmr.2011.587 · 1.48 Impact Factor