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. 2002 Mar;70(3):1143-9.
doi: 10.1128/IAI.70.3.1143-1149.2002.

Cross-protective immunity of mice induced by oral immunization with pneumococcal surface adhesin a encapsulated in microspheres

Jun-Young Seo  1 , Seung Yong Seong, Byung-Yoon Ahn, Ick Chan Kwon, Hesson Chung, Seo Young Jeong
Affiliations

Cross-protective immunity of mice induced by oral immunization with pneumococcal surface adhesin a encapsulated in microspheres

Jun-Young Seo et al. Infect Immun. 2002 Mar.

Abstract

The global use of a capsular polysaccharide-based pneumococcal vaccine has been limited because of serotype-specific protection and poor effectiveness in individuals with low immunocompetency. The mucosal immune system develops earlier in infants and lasts longer in the elderly than does the systemic immune system. Furthermore, mucosal immunization is beneficial for AIDS patients, because human immunodeficiency virus-infected subjects can develop normal mucosal antibody responses even in late clinical phases. For these reasons, we evaluated recombinant pneumococcal surface adhesin A (rPsaA) of Streptococcus pneumoniae in terms of cross-protective immune responses after oral delivery. Encapsulated rPsaA provided higher immunogenicity than naked rPsaA. Coencapsulation or codelivery of the cholera toxin (CT) B subunit (CTB) and CT also increased the immunogenicity of rPsaA. Cross-protective immunities against five strains of S. pneumoniae (types 4, 6B, 14, 19F, and 23F) were induced after oral immunization with microencapsulated rPsaA. Lung colonization and septicemia caused by the five serotypes were significantly inhibited by oral immunization with microencapsulated rPsaA. These results suggest that rPsaA coencapsulated with CTB can be used as an oral vaccine to induce cross-protective immunity for the prevention of pneumococcal infection.

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Figures

FIG. 1.
FIG. 1.
Expression of fusion protein (rPsaA-intein-CBD) (A), identification of the purified rPsaA protein by SDS-PAGE (B), and Western blot analysis (C). (A) Fusion proteins were expressed in E. coli XL1-Blue at 37, 30, 25, or 20°C. Insoluble and soluble proteins were recovered in pellets (▴) and supernatants (▵), respectively. The density of the fusion protein band was determined with TINA software and plotted against temperature. od, optical density units. (B and C) After purification, the rPsaA solution was separated on 10% polyacrylamide gels (B) and probed with sera from rabbits immunized with S. pneumoniae (C). The numbers in panel B indicate molecular masses of marker proteins. An arrow indicates the purified rPsaA protein (35 kDa).
FIG. 2.
FIG. 2.
Microspheres entrapping rPsaA (ePsaA), examined using a scanning electron microscope.
See this image and copyright information in PMC

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