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Journal of Medical Microbiology logo - Volume 67, Issue 3, 2018

Volume 67, Issue 3

Volume 67, Issue 3, 2018

  • Prevention and Therapy

      • The double adjuvants LTB and CpG significantly enhanced the immuno-protective effects of recombinant GIT derived from and in mice

        https://doi.org/10.1099/jmm.0.000666

        In this study, we prepared GapC-IsdB-TRAP (GIT) proteins plus heat-labile enterotoxin B (LTB) as an intra-molecular adjuvant, together with CpG to further enhance its immunogenicity.

        Initially, the target genes were acquired and inserted into pET-32a (+) vectors to express LTB–GIT protein. LTB–GIT expression was confirmed by Western blotting and its immunocompetence was estimated through ELISA. Further, we immunized BALB/c mice with the LTB–GIT plus CpG adjuvant. After the second immunization, the antigen-specific CD4 cell responses for IFN-γ, IL-2, IL-4 and IL-10 were monitored by intracellular cytokine staining (ICS) assay. After the third immunization, the level of IgG antibodies in the serum from immunized groups was assessed by ELISA, and the protective immune response was appraised by and challenge.

        The ELISA results showed that the OD value of the LTB–GIT group was significantly higher than that of the BSA group. The group immunized with LTB–GIT plus CpG exhibited significantly stronger CD4 T cell responses for IFN-γ, IL-2, IL-4 and IL-10 compared to the group immunized with LTB–GIT, GIT alone orLTB–GIT plus CpG. In addition, the group immunized with LTB–GIT plus CpG generated the highest level of IgG antibodies against GIT among all of the groups, and our results also showed that LTB–GIT plus CpG markedly improved the survival percentage of mice compared to other groups.

        We confirmed that the novel double adjuvants, LTB and CpG, are able to significantly improve GIT-induced immune responses. This formula could be a promising strategy for enhancing the immune efficacy of multi-subunit vaccines against and streptococcal infection.

    • Immunogenicity in chickens with orally administered recombinant chicken-borne expressing FimA and OmpC antigen of O78 avian pathogenic

      https://doi.org/10.1099/jmm.0.000679

      Avian colibacillosis is responsible for economic losses to poultry producers worldwide. To combat this, we aimed to develop an effective oral vaccine for chicken against O78 avian pathogenic (APEC) infection through a delivery system.

      Eight strains isolated from the intestines of broiler chickens were evaluated based on their adherence ability to assess their potential as a delivery vector. Fimbrial subunit A (FimA) and outer-membrane protein C (OmpC) of APEC with and without fusion to dendritic cell-targeting peptide (DCpep) and microfold cell-targeting peptide (Co1) were displayed on the surface of M-11 and yielded vaccine groups (pPG-ompC-fimA/M-11 and pPG-ompC-fimA-Co1-DCpep/M-11, respectively). The colonization of the recombinant strains was assessed and the immunogenicity and protective efficacy of orally administered recombinant strains in chickens were evaluated.

      The colonization of the recombinant strains revealed no significant differences between the recombinant and wild-type strains. Chickens orally administered with vaccine groups showed significantly higher levels of OmpC/FimA-specific IgG in serum and mucosal IgA in cecum lavage, nasal lavage and stool compared to the pPG/M-11 group. After challenge with APEC CVCC1553, better protective efficacy was observed in chickens orally immunized with pPG-ompC-fimA/M-11 and pPG-ompC-fimA-Co1-DCpep/M-11, but no significant differences were observed between the two groups.

      Recombinant chicken-borne M-11 showed good immunogenicity in chickens, suggesting that it may be a promising vaccine candidate against APEC infections. However, the activity of mammalian DCpep and Co1 was not significant in chickens.

    • The effect of P38 MAP kinase inhibition in a mouse model of influenza

      https://doi.org/10.1099/jmm.0.000684

      Influenza viruses are a common cause of human respiratory infections, resulting in epidemics of high morbidity and mortality. We investigated the effect of a novel mitogen-activated protein kinase (MAPK) inhibitor and in a murine influenza model to further explore whether p38 MAPK inhibition could reduce viral replication.

      , the antiviral effect of p38 MAPK inhibitor BCT194 was evaluated in differentiated human bronchial epithelial cells (HBECs); , female BALB/c mice were infected intranasally with 150 pfu of influenza H1N1 A/Puerto Rico/8/34 and treated with BCT197 (a closely related p38 MAPK inhibitor with an IC value of<1 µM, currently in clinical testing), dexamethasone or oseltamivir (Tamiflu) starting 24 h post infection. Body weight, bronchoalveolar lavage cells, cytokines, total protein and lactate dehydrogenase as well as serum cytokines were measured; a subset of animals was evaluated histopathologically.

      p38MAP kinase inhibition with BCT194 had no impact on influenza replication in HBECs. When examining BCT197 , and comparing to vehicle-treated animals, reduced weight loss, improvement in survival and lack of impaired viral control was observed at BCT197 concentrations relevant to those being used in clinical trials of acute exacerbations of chronic obstructive pulmonary disease; at higher concentrations of BCT197 these effects were reduced.

      Compared to vehicle treatment, BCT197 (administered at a clinically relevant concentration) improved outcomes in a mouse model of influenza. This is encouraging given that the use of innate inflammatory pathway inhibitors may raise concerns of negative effects on infection regulation.

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