Innate inflammatory responses to the Gram-positive bacterium Lactococcus lactis

Lactic acid bacteria in the prevention of pneumococcal respiratory infection: Future opportunities and challenges

“…These findings were confirmed recently by other authors, who demonstrated that L. lactis NZ9000 is able to stimulate the production of both IL-12 and IL-10 by bone marrow derived DCs in vitro [36]. In addition, we demonstrated that the oral immunization of young mice with L. lactis-PppA is able to induce the production of specific IgA and IgG antibodies in the respiratory tract [106].…”

“…When studying the activation of the recruited macrophages and the levels of TNF-α in BALF after the challenge with the pathogen, we found that mice treated orally with LAB showed higher BALF TNF-α values and NBT + cells percentages than mice in the control group [13,[16][17][18], which would indicate that LAB treatments would be capable of improving macrophage-mediated antigen presentation. In addition, it has been demonstrated in vitro that L. lactis NZ 9000 cells are able to up regulate the expression of MHC-II and CD86 co-stimulatory molecules in bone marrow derived DCs [35,36]. During the generation of an efficient effector immune response DCs have to overcome suppression by Treg cells.…”

Lactococcus lactisas an adjuvant and delivery vehicle of antigens against pneumococcal respiratory infections

“…Recent in vitro studies showed that L. lactis NZ9000 has intrinsic adjuvant properties since it is able to stimulate the maturation of dendritic cells derived from bone marrow and to induce the production of cytokines with adjuvant properties such as IL-1β. 93 These properties and the adjuvant activities of L. lactis NZ9000 demonstrated in vivo in our laboratory would explain the efficacy of the oral immunization with L. lactis PppA to stimulate the specific immune response against the S. pneumoniae antigen in young mice. The analysis of IgG subtypes showed that L. lactis PppA immunization stimulated a mixture of the Th1 and Th2 response, which agrees with our previous studies in adult mice where oral immunization with L. lactis PppA was able to induce the production of IL-4 and INF-γ producing spleen cells.…”

“…91 Recent in vitro studies also showed that L. lactis NZ9000 is able to stimulate the production of both IL-12 and IL-10 by bone marrow derived dendritic cells. 93 Oral immunization of young mice with L. lactis PppA was also able to induce the production of specific IgA-and IgGtype antibodies in the respiratory tract. The mucosal and systemic antibodies induced by the oral immunization with L. lactis PppA afforded protection to young mice against an S. pneumoniae respiratory infection, although their bacterial counts in lung and hemocultures after challenge with different serotypes of the pathogen were significantly higher than the ones previously found in adult mice.…”

“…Moreover, recent findings demonstrated in vitro that L. lactis NZ 9000 cells are able to upregulate the expression of MHC-II and CD86 co-stimulatory molecules in bone marrow derived dendritic cells. 61 Finally, in the bone marrow cells of mice the nasal administration of L. lactis showed: (a) a decrease in the percentage of the post-mitotic pool (metamyelocytes, band cells and neutrophils), probably related to the release of mature neutrophils and the production of granulocytes in response to inflammatory signals; 62 (b) an increase in bone marrow CD19 + cells, possibly related to the increase in serum anti-pneumococcal IgG; (c) a decrease in CD4 + cells, probably caused by the mobilization of cells towards the site of infection. 49 Then, preventive nasal administration of L. lactis at the appropriate dose was able to induce a local and systemic specific immune response.…”