14th ICID - Poster Abstracts - International Society for Infectious ...

When citing these abstracts please use the following reference:
Author(s) of abstract. Title of abstract [abstract]. Int J Infect Dis 2010;14S1: Abstract number.
Please note that the official publication of the International Journal of Infectious Diseases 2010, Volume 14, Supplement 1
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Final Abstract Number: 83.005
Session: Vaccines and Vaccine Development
Date: Thursday, March 11, 2010
Time: 12:30-13:30
Room: Poster & Exhibition Area/Ground Level
Type: Poster Presentation
Protection against pneumococcal nasopharyngeal colonization in mice immunized with PspC
(“Pneumococcal Surface Protein C”)-based vaccines formulated with whole bacteria as carriers or
adjuvants
M. De Lúcia Hernani, D. M. Ferreira, P. C. D. Ferreira, A. T. Moreno, E. Miyaji, P. Ho, M. L.
Sarno de Oliveira
Instituto Butantan, Sao Paulo, Brazil
Background: Streptococcus pneumoniae (pneumococcus) is responsible for the majority of
pneumonia cases around the world. Despite the effectiveness of conjugate vaccines, the costs of
the available formulations are prohibitive for mass vaccination in developing countries. Protein
antigens are alternatives for the constitution of low costs-formulations that can elicit immunity to
different pneumococcal serotypes. PspC is a virulence factor that plays a role in the adhesion of
the pathogen to epithelial cells and evasion from the immune system. Intact bacteria display
adjuvant activities when administered in association with antigens, through the binding of their
components to receptors present on immune cells surface.
Methods: In this work, mucosal vaccines composed of PspC and two different bacteria as
carriers and/or adjuvants were tested in mice. The first strategy consisted in Lactobacillus casei
expressing PspC (L. casei-PspC), as a live vaccine. The second consisted in the combination of
recombinant PspC with the whole cell pertussis vaccine (WCPV).
Results: Nasal immunization of mice with L. casei-PspC did not stimulate the production of
systemic and mucosal anti-PspC antibodies. Despite the absence of specific antibodies, this
vaccine inhibited pneumococcal nasopharyngeal colonization of immunized mice, when
compared with mice inoculated with saline or L. casei. In this same model, sublingual
immunization with L. casei-PspC did not produce a significant effect on pneumococcal
colonization. On the other hand, nasal immunization with PspC-WCPV induced high levels of
anti-PspC antibodies. Mice immunized with PspC-WCPV presented a significant inhibition of
pneumococcal colonization, when compared with mice inoculated with saline or WCPV. The
reduction in pneumococcal colonization was much more accentuated for the PspC-WCPV
formulation than for L. casei-PspC. Analysis of cytokine secretion by spleen cells from mice 5
days after the colonization challenge showed two different patterns. Mice immunized with L.
casei-PspC displayed a dramatic reduction in IFN-g and TNF-a secretion whereas mice
immunized with PspC-WCPV displayed increased IFN-g and IL-17 secretion.
Conclusion: Our results indicate that two different mechanisms are likely to be involved in the
protection elicited by both vaccines. The mechanisms elicited by PspC-WCPV seem to be more
effective in the control of pneumococcal nasopharyngeal carriage.
Financial support: FAPESP, CNPq, Fundação Butantan.