title: Characterization of the antibody response elicited by immunization with pneumococcal surface protein A (PspA) as recombinant protein or DNA vaccine and analysis of protection against an intranasal lethal challenge with Streptococcus pneumoniae.
abstract: Pneumococcal surface protein A (PspA) is an important candidate for a vaccine against pneumococcal infections. DNA vaccines expressing PspA were shown to protect mice against intraperitoneal and colonization challenge models in mice. We now show that a DNA vaccine expressing PspA from clade 4 (pSec-pspA4Pro) is also able to elicit protection against an intranasal lethal challenge model at levels similar to the recombinant protein PspA4Pro adjuvanted with alum. PspA4Pro + alum induced an IgG response characterized by a high IgG1/IgG2a ratio, leading to a lack of binding of anti-PspA IgG2a antibodies to intact pneumococci in vitro, which is in contrast to the response elicited by pSec-pspA4Pro. Epitopes recognized by the sera were mapped and antibodies induced by immunization with PspA4Pro + alum showed positive reaction with several synthetic peptides, mostly located in the first half of the protein. On the other hand, antibodies induced by the DNA vaccine showed reactivity with only two peptides. Though both strategies were protective against the intranasal lethal challenge model, the elicited humoral responses differ significantly, with the detection of important differences in the Fc (IgG1/IgG2a ratios) and Fab (recognized epitopes) regions of the induced antibodies.
authors.affiliation: Centro de Biotecnologia, Instituto Butantan, Av Vital Brasil, 1500, 05503-900, São Paulo, SP, Brazil.
authors.forename: Cintia F M
authors.initials: CF
authors.lastname: Vadesilho
authors.forename: Daniela M
authors.initials: DM
authors.lastname: Ferreira
authors.forename: Adriana T
authors.initials: AT
authors.lastname: Moreno
authors.forename: Carlos
authors.initials: C
authors.lastname: Chavez-Olortegui
authors.forename: Ricardo A
authors.initials: RA
authors.lastname: Machado de Avila
authors.forename: Maria Leonor S
authors.initials: ML
authors.lastname: Oliveira
authors.forename: Paulo L
authors.initials: PL
authors.lastname: Ho
authors.forename: Eliane N
authors.initials: EN
authors.lastname: Miyaji
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000534:Alum Compounds / Q000008:administration & dosage; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology*; D004195:Disease Models, Animal; D018604:Epitope Mapping; D005260:Female; D007074:Immunoglobulin G / Q000097:blood; D051379:Mice; D008807:Mice, Inbred BALB C; D011008:Pneumococcal Infections / Q000276:immunology / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D016019:Survival Analysis; D014611:Vaccination / Q000379:methods*; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D022223:Vaccines, Subunit / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D000534:Alum Compounds; D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D007074:Immunoglobulin G; D022242:Pneumococcal Vaccines; D011994:Recombinant Proteins; D019444:Vaccines, DNA; D022223:Vaccines, Subunit; D014614:Vaccines, Synthetic; C051592:pneumococcal surface protein A; C041524:aluminum sulfate