Administration of a probiotic associated with nasal vaccination with inactivated Lactococcus lactis-PppA induces effective protection against pneumoccocal infection in young mice

VINTIÑI ELISA; VILLENA JULIO; ALVAREZ SUSANA; MEDINA MARCELA

CLINICAL AND EXPERIMENTAL IMMUNOLOGY

Blackwell

Año: 2010 vol. 153 p. 351 - 362

0009-9104

Streptococcus pneumoniae is a serious public health problem, especially in developing countries, where available vaccines are not part of the vaccination calendar. We evaluated different respiratory mucosa immunization protocols that included the nasal administration of Lactococcus lactis-pneumococcal protective protein A (PppA) live, inactivated, and in association with a probiotic (Lc) to young mice.  The animals that received Lc by the oral and nasal route presented  the highest levels of  IgA and IgG anti-PppA antibodies in bronchoalveolar lavages (BAL) and IgG in serum, which no doubt contributed to the protection against infection. However, only the groups that received the live and inactivated vaccine associated with the oral administration of the probiotic were able to prevent lung colonization by S. pneumoniae serotypes 3 and 14 in a respiratory infection model. This fact would be related to a preferential stimulation of the Th1 cells at the local and systemic level and with a moderate Th2 and Th17 response, shown by the cytokine profile induced in BAL and by the results of the IgG1/IgG2a ratio at the local and systemic level. Nasal immunization with the inactivated recombinant strain associated with oral Lc administration was able to stimulate the specific cellular and humoral immune response and afford protection against the challenge with the two S. pneumoniae serotypes. The results obtained show the probiotic-inactivated vaccine association as a valuable alternative for application to human health, especially in at-risk populations, and are the first report of a safe and effective immunization strategy using an inactivated recombinant strain.