title: Nasal immunization of mice with Lactobacillus casei expressing the pneumococcal surface protein C primes the immune system and decreases pneumococcal nasopharyngeal colonization in mice.
abstract: Streptococcus pneumoniae colonizes the upper respiratory tract of healthy individuals, from where it can be transmitted to the community. Occasionally, bacteria invade sterile niches, causing diseases. The pneumococcal surface protein C (PspC) is a virulence factor that is important during colonization and the systemic phases of the diseases. Here, we have evaluated the effect of nasal or sublingual immunization of mice with Lactobacillus casei expressing PspC, as well as prime-boosting protocols using recombinant PspC, on nasopharyngeal pneumococcal colonization. None of the protocols tested was able to elicit significant levels of anti-PspC antibodies before challenge. However, a significant decrease in pneumococcal recovery from the nasopharynx was observed in animals immunized through the nasal route with L. casei-PspC. Immune responses evaluated after colonization challenge in this group of mice were characterized by an increase in mucosal anti-PspC immunoglobulin A (IgA) 5 days later, a time point in which the pneumococcal loads were already low. A negative correlation between the concentrations of anti-PspC IgA and pneumococcal recovery from the nasopharynx was observed, with animals with the lowest colonization levels having higher IgA concentrations. These results show that nasal immunization with L. casei-PspC primes the immune system of mice, prompting faster immune responses that result in a decrease in pneumococcal colonization.
authors.affiliation: Centro de Biotecnologia, Instituto Butantan, São Paulo, SP, Brazil.
authors.forename: Marília de Lúcia
authors.initials: Mde L
authors.lastname: Hernani
authors.forename: Patrícia Cristina Duarte
authors.initials: PC
authors.lastname: Ferreira
authors.forename: Daniela Mulari
authors.initials: DM
authors.lastname: Ferreira
authors.forename: Eliane Namie
authors.initials: EN
authors.lastname: Miyaji
authors.forename: Paulo Lee
authors.initials: PL
authors.lastname: Ho
authors.forename: Maria Leonor Sarno
authors.initials: ML
authors.lastname: Oliveira
mesh_terms: D000281:Administration, Intranasal; D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis / Q000097:blood; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D016207:Cytokines / Q000378:metabolism; D005260:Female; D007114:Immunization / Q000379:methods; D007070:Immunoglobulin A / Q000032:analysis; D007074:Immunoglobulin G / Q000097:blood; D007780:Lacticaseibacillus casei / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009305:Nasopharynx / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D011008:Pneumococcal Infections / Q000276:immunology / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage / Q000276:immunology*; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D018709:Statistics, Nonparametric; D013296:Streptococcus pneumoniae / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D016207:Cytokines; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D022242:Pneumococcal Vaccines; D011994:Recombinant Proteins; C110344:SpsA protein, Streptococcus pneumoniae