Outer Membrane Vesicles from Neisseria Meningitidis (Proteossome) Used for Nanostructured Zika Virus Vaccine Production.

The increase of Zika virus (ZIKV) infections in Brazil in the last two years leaves a prophylactic measures on alert for this new and emerging pathogen. Concerning of our positive experience, we developed a new prototype using Neisseria meningitidis outer membrane vesicles (OMV) on ZIKV cell growth in a fusion of OMV in the envelope of virus particles. The fusion of nanoparticles resulting from outer membrane vesicles of N. meningitidis with infected C6/36 cells line were analyzed by Nano tracking analysis (NTA), zeta potential, differential light scattering (DLS), scan and scanning transmission eletronic microscopy (SEM and STEM) and high resolution mass spectometry (HRMS) for nanostructure characterization. Also, the vaccination effects were viewed by immune response in mice protocols immunization (ELISA and inflammatory chemokines) confirmed by Zika virus soroneutralization test. The results of immunizations in mice showed that antibody production had a titer greater than 1:160 as compared to unvaccinated mice. The immune response of the adjuvant and non-adjuvant formulation activated the cellular immune response TH1 and TH2. In addition, the serum neutralization was able to prevent infection of virus particles in the glial tumor cell model (M059J). This research shows efficient strategies without recombinant technology or DNA vaccines.

An in vitro model to study the effect of antibodies and cell receptor analogues on meningococcal adherence to human oroepithelial cells.

We have investigated different experimental schedules to achieve adherence of Neisseria meningitidis group B to cultured and buccal epithelial cells (BEC) and the effect of antibodies and receptor analogues on bacterial adherence. No adherence of meningococcus was observed when HeLa, HEp-2 or KB cells were used, but high rates of adherence to BEC occurred. The effect of antibodies on bacterial adherence was studied in assays carried out in the presence of saliva and serum collected from convalescing children with meningococcal meningitis and children vaccinated with VAMENGOC B-C. Both saliva and serum from the convalescent patients inhibited the adherence of meningococci, but saliva and serum from vaccinated children did not, corroborating our previous data of a poor antibody response induced by this vaccine. Human colostrum did not affect meningococcal adherence despite the presence of antibodies to N. meningitidis detected by ELISA. Inhibition of adherence by sera from an immunized horse, rabbits and mice, as well as by cell receptor analogues (outer-membrane complex and purified polysaccharide C), was observed. Our results show that up to now BEC continue to be the best cells to study meningococcal adherence and the effect of adherence inhibitors.

An in vitro model to study the effect of antibodies and cell receptor analogues on meningococcal adhrence to human oroepithelial cells

We have investigated different experimental schedules to achieve adherence of Neisseria meningitidis group B to cultured and buccal epithelial cells (BEC) and the effect of antibodies and receptor analogues on bacterial adherence. No adherence of meningococcus was observed when HeLa, HEp-2 or KB cells were used, but high rates of adherence to BEC occurred. The effect of antibodies on bacterial adherence was studied in assays carried out in the presence of saliva and serum collected from convalescing children with meningococcal meningitis and children vaccinated with VAMENGOC B-C. Both saliva and serum from the convalescent patients inhibited the adherence of meningococci, but saliva and serum from vaccinated children did not, corroborating our previous data of a poor antibody response induced by this vaccine. Human colostrum did not affect meningococcal adherence despite the presence of antibodies to N. meningitidis detected by ELISA. Inhibition of adherence by sera from an immunized horse, rabbits and mice, as well as by cell receptor analogues (outer-membrane complex and purified polysaccharide C), was observed. Our results show that up to now BEC continue to be the best cells to study meningococcal adherence and the effect of adherence inhibitors.

The antimeningococcal vaccine VAMENGOC B-C induced poor serum and salivary antibody response in young Brazilian children.

In 1989 about 2.3 million Brazilian children received the antimeningococcal vaccine VAMENGOC B-C (Havana, Cuba). We evaluated the serum and secretory immune response of vaccinated children by enzyme-linked immunosorbent assay with outer membrane complex antigens. Western blotting and bacterial adherence inhibition assays with human buccal epithelial cells were performed with some of the samples. Serum and salivary antibody concentrations to Neisseria meningitidis Group B of vaccinated children < 4 years old were not significantly higher than those of nonvaccinated children, as observed in convalescing patients used as positive controls. Older children (4 to 6 years old) presented a slight increase in antibody OD indexes. Sera and saliva from vaccinated children showed a weak reaction with meningococcal antigen by Western blotting and were unable to inhibit significantly the adherence of N. meningitidis B to buccal epithelial cells. These data suggest that this vaccine induced a poor serum and salivary antibody response in the population studied.

Nasal secretions of Neisseria lactamica carriers have an inhibitory effect on Neisseria meningitidis attachment to human oroepithelial cells

As secreçöes nasais de voluntários colonizados por N. lactamica inibem a aderência de N. Lactamica e de meningococos dos grupos A e B à células oroepiteliais humanas, "in vitro". A aderência, nas amostras de Neisseria testadas, decorre da presença de adesinas näo-fimbriais que parecem possuir antígenos comuns. A despeito do surgimento de marcante atividade antiadesiva nas secreçöes nasais os voluntários persistiram como portadores de N. lactamica. A erradicaçäo do estado de portador parece assim ser dependente da açäo de diferentes fatores

Nasal secretions of Neisseria lactamica carriers have an inhibitory effect on Neisseria meningitidis attachment to human oroepithelial cells.

Nasal secretions of volunteers colonized by N. lactamica impaired the attachment of N. lactamica and of meningococci of groups A and B to oroepithelial cells. Bacterial adherence was found to be mediated by nonpiliated adhesins with antigen(s) which probably are shared by the strains tested. Although a strong attachment-inhibiting activity arises in their nasal secretions, volunteers remained colonized by N. lactamica. This evidence suggest that the eradication of Neisseria carriage is a multifactorial event.