Host immunity in the protective response to nasal immunization with a pneumococcal antigen associated to live and heat-killed Lactobacillus casei

Background: At present, available pneumococcal vaccines have failed to eradicate infections caused by S. pneumoniae. Search for effective vaccine continues and some serotype independent pneumococcal proteins are considered as candidates for the design of new vaccines, especially a mucosal vaccine, since pneumococci enter the body through mucosal surfaces. Selection of the appropriate adjuvant is important for mucosal vaccines, and lactic acid bacteria (LAB) with immunostimulant properties are promissory candidates. In this work, we assessed the adjuvant effect of a probiotic strain, Lactobacillus casei (L. casei), when nasally administered with a pneumococcal antigen (pneumococcal protective protein A: PppA) for the prevention of pneumococcal infection. Adjuvanticity of both live (LcV) and heat-killed (LcM) was evaluated and humoral and cellular antigen-specific immune response was assessed in mucosal and systemic compartments. The potential mechanisms induced by nasal immunization were discussed.Results: Nasal immunization of young mice with PppA+LcV and PppA+LcM induced anti-PppA IgA and IgG antibodies in mucosal and systemic compartments and levels of these specific antibodies remained high even at day 45 after the 3rd Immunization (3rd I). These results were correlated with IL-4 induction by the mixture of antigen plus LcV and LcM. Also, PppA+Lc (V and M) induced stimulation of Th1 and Th17 cells involved in the defence against pneumococci. The protection against pneumococcal respiratory challenge at day 30 after the 3rd I showed that PppA+LcV and PppA+LcM immunizations significantly reduced pathogen counts in nasal lavages while prventing their passage into lung and blood. Survival of mice immunized with the co-application of PppA plus LcV and LcM was significantly higher than in mice immunized with PppA alone and control mice when intraperitoneal challenge was performed. No significant differences between the treatments involving LcV and LcM were found.Conclusions: Live and heat-killed L. casei enhanced the antigen-specific immune response when administered nasally with a pneumococcal antigen. Considering the potential risk associated with live bacteria, the design of a nasal vaccine based on pneumococcal antigens and heat-killed L. casei emerges as a safe and effective strategy for the prevention of pneumococcal infections and opens new possibilities of application of dead LAB as adjuvants in vaccine formulations against other pathogens.Fil: Vintiñi, Elisa Ofelia. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Medina, Marcela Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentin

Immunomodulatory and Anti-Inflammatory Activity Induced by Oral Administration of a Probiotic Strain of

The aim of this work was to study the effect of the long-term cyclic administration of the probiotic strain of Lactobacillus ( L .) casei CRL 431 as a mucosal immunomodulator of the immune cells associated with the lamina propria of the small intestine, bronchus and other immune cells not associated with mucosal tissues, such as peritoneal macrophages. BALB/c mice were orally administered with a suspension of Lc 10 9 cfu/day/animal in non-fat milk (NFM) 10% for two consecutive days, the optimal dose selected in previous studies to reach protective immunity. This administration was repeated cyclically every 5 days for 98 days. Mice in the control group received only NFM 10%. Samples were taken after two days of L. casei administration and every 14 days until day 98. The small intestine and lungs were removed for histological slices preparation. Haematoxilin-eosin stains were made for histological studies of the small intestine. The number of IgA producing cells in the lamina propria of the small intestine and in bronchus was determined by immunofluorescence assays. Regulatory (IL-4, IL-10) and proinflammatory (TNF-α, INF-γ) cytokines were measured in the gut. Peritoneal macrophages were collected during the same periods for phagocytosis assays. We determined an increase in the number of IgA + cells in the lamina propria of the small intestine in all the periods assayed and in BALT only until day 28. The cytokines studied (IL-10, IL-4, TNF-α and INF-γ) increased in most of the periods assayed, the effect being more remarkable for the anti-inflammatory cytokines such as IL-4 and IL-10. INF-γ was also increased but no modifications in the histological studies of the small intestine were observed, suggesting other roles for this cytokine The phagocytic activity of PM increased for most of the periods assayed. We demonstrated that long-term cyclic oral L. casei administration favors mucosal immunity and modulates the immune response to maintain the homeostasis at the mucosal level

Contents of CaCO3 in the couplets marl-limestone of the Maastrichtian and the Danian at the Sopelana, Basque Arc: grey facies versus red facies

The Sopelana sea-cliff section exposes a continuous marl-limestone alternation from the Lower Maastrichtian to the Danian, in the deep Basque Arc domain. The high-resolution analysis (% CaCO3) of the Lower- Upper Maastrichtian couplets confirms a simple and regular layout versus a more complex behaviour of the Danian couplets. The marl and limestone mean values of the Upper Maastrichtian point out a continental debris enrichment. The early entry of deep, cold, oxygenated water produces a gradual (grey/ yellowgreenish/ red) change of coloration in the Lower Maastrichtian couplets. It is the beginning of the Cretaceous oceanic red beds (CORB´s). The “bleaching” around macrofossil nucleus and small fractures in the red facies shows a small diagenetic stage due to the influx of reducing fluid

Immunological evaluation of the intestinal mucosa of broiler chicks treated with Lactobacillus Spp. and challenged with Salmonella Enteritidis

This study aimed at the antibody production by intestinal mucosa of broilers chicks were orally inoculated with Lactobacillus spp. at one and/or 21 days of age, and subsequently challenged with Salmonella enterica, subspecies enterica, serotype Enteritidis (S. Enteritidis). A total number of 288 drug-free broiler chicks was divided into 6 groups (groups A, B, C, D, E, and F), according to age at Lactobacillus spp. inoculation and SE challenge. The intestinal mucosa immune response was determined as the production of immunoglobulin A against S. Enteritidis, and evaluated by the Enzyme-Linked Immunosorbent Assay (ELISA) technique in intestinal washing fluid. Groups treated with Lactobacillus spp. presented higher IgA production only when the chicks were challenged with S. Enteritidis at 21 days of age. Nevertheless, the expected stimulus for intestinal mucosa antibody production induced by Lactobacillus spp was observed in only some of the treated groups, demonstrating that the protocol utilized in the present experiment resulted in few beneficial effects for chicks, particularly during the first days of life