Nasal administration of a non-viable Lactobacillus casei to infant mice modulates lung damage induced by Poly I:C and hyperreactivity in airways.

Viral respiratory infections caused by RNA viruses are one of the most important diseases around the world. The aim of this work was to study whether the nasal administration of non-viable Lactobacillus casei (LcM) was able to enhance respiratory antiviral defenses in young mice challenged with Poly I:C. Three-week-old BALB/c mice were nasally challenged with Poly I:C, used to mimic the pro-inflammatory state of lung infections caused by RNA viruses.

Non-Viable Lactobacillus Casei Beneficially Modulates Poly I:C Immune Response in Co-Cultures of Human Cells.

Background: Polyinosinic:polycytidylic acid (Poly-IC) has been used as a viral stimulus to mimic in vivo and in vitro infection induced by some viruses.

Objective: To determine whether non-viable Lactobacillus casei CRL431 (LcM) can modulate the immune response induced by Poly I:C in co-culture models of peripheral blood mononuclear cells (PBMC) and A549 cells.

Methods: T and NK cell activation was evaluated by flow cytometry and levels of TNF-α, IFN-γ, IL-10, IL-29, and IL-17 by ELISA.

Decrease in lactobacilli in the intestinal microbiota of celiac children with a gluten-free diet, and selection of potentially probiotic strains.

The intestinal microbiota would be implicated in pathology associated with celiac disease caused by an abnormal immune system reaction against gluten present in cereal grains. The objectives of this work were to detect through basic methods the changes in the composition of the most common genera of bacteria from the intestinal microbiota of symptom-free celiac disease children with a gluten-free diet compared with healthy children from Tucumán and to select lactobacilli (Lb) strains with probiotic potential from the feces of healthy children. Results demonstrated that the feces of celiac children with a gluten-free diet showed significantly lower counts of Lb (P < 0.

Safety of a nasal vaccine against Streptococcus pneumoniae using heat-killed Lactobacillus casei as adjuvant.

Streptococcus pneumoniae is a highly important respiratory pathogen that causes infections in children, elderly people and immunocompromised people around the world. Pneumococcal vaccines licensed did not reach to eradicate the pneumococcal infection. In a previous study was demonstrated the effectiveness of a nasal experimental vaccine that consisted in a pneumococcal protective protein A (PppA) co-administrated with heat-killed-Lactobacillus casei (LcM), in mice model of respiratory pneumococcal challenge.

Immune response in nasopharynx, lung, and blood elicited by experimental nasal pneumococcal vaccines containing live or heat-killed lactobacilli as mucosal adjuvants.

This work analyzes the humoral and cellular immune responses induced by live (LcV) and heat-killed (LcM) Lactobacillus casei associated with the pneumococcal antigen (P-Ag) at the nasopharynx level, considering nasal-associated lymphoid tissue (NALT) as the primary inductive site of the mucosal immune system, and lung and blood as effector sites. Levels of P-Ag IgA and IgG antibodies, main types of B and T cells, and cytokines in mucosal and systemic compartments were evaluated. The results showed that both LcM+P-Ag and LcV+P-Ag vaccines effectively induced IgA and IgG anti-P-Ag Abs in the upper and lower respiratory tract and plasma.

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.

Lactococcus lactis as an adjuvant and delivery vehicle of antigens against pneumococcal respiratory infections.

Most studies of Lactococcus lactis as delivery vehicles of pneumococcal antigens are focused on the effectiveness of mucosal recombinant vaccines against Streptococcus pneumoniae in animal models. At present, there are three types of pneumococcal vaccines: capsular polysaccharide pneumococcal vaccines (PPV), protein-polysaccharide conjugate pneumococcal vaccines (PCV) and protein-based pneumococcal vaccines (PBPV). Only PPV and PCV have been licensed.

Stimulation of respiratory immunity by oral administration of Lactococcus lactis.

This work demonstrates that non-recombinant Lactococcus lactis NZ, administered by the oral route at the proper dose, is able to improve resistance against pneumococcal infection. Lactococcus lactis NZ oral administration was able to improve pathogen lung clearance, increased survival of infected mice, and reduced lung injuries. This effect was related to an upregulation of the respiratory innate and specific immune responses.

Nasal administration of Lactococcus lactis improves local and systemic immune responses against Streptococcus pneumoniae.

Lactococcus lactis NZ9000 is a non-pathogenic non-invasive bacterium extensively used for the delivery of antigens and cytokines at the mucosal level. However, there are no reports concerning the per se immunomodulatory capacity of this strain. The aim of the present study was to investigate the intrinsic immunostimulating properties of the nasal administration of L.

Nasal immunization with Lactococcus lactis expressing the pneumococcal protective protein A induces protective immunity in mice.

Nisin-controlled gene expression was used to develop a recombinant strain of Lactococcus lactis that is able to express the pneumococcal protective protein A (PppA) on its surface. Immunodetection assays confirmed that after the induction with nisin, the PppA antigen was predictably and efficiently displayed on the cell surface of the recombinant strain, which was termed L. lactis PppA.

Effect of lactobacilli administration in the vaginal tract of mice: evaluation of side effects and local immune response by local administration of selected strains.

Lactobacilli are the predominant microorganisms in the vaginal tract of human and some homeothermic animals. They can maintain the ecological equilibrium of the tract by protecting against pathogenic microorganisms. In the last few years, there has been an increased tendency to use probiotic microorganisms to restore the ecological equilibrium and to protect against infections.