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1.
BMC Microbiol ; 16(1): 165, 2016 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-27464881

RESUMO

BACKGROUND: Chlamydia trachomatis is a human pathogen which causes a number of pathologies, including genital tract infections in women that can result in tubal infertility. Prevention of infection and disease control might be achieved through vaccination; however, a safe, efficacious and cost-effective vaccine against C. trachomatis infection remains an unmet medical need. C. trachomatis major outer membrane protein (MOMP), a ß-barrel integral outer membrane protein, is the most abundant antigen in the outer membrane of the bacterium and has been evaluated as a subunit vaccine candidate. Recombinant MOMP (rMOMP) expressed in E. coli cytoplasm forms inclusion bodies and rMOMP extracted from inclusion bodies results in a reduced level of protection compared to the native MOMP in a mouse challenge model. RESULTS: We sought to target the recombinant expression of MOMP to the E. coli outer membrane (OM). Successful surface expression was achieved with codon harmonization, utilization of low copy number vectors and promoters with moderate strength, suitable leader sequences and optimization of cell culture conditions. rMOMP was extracted from E. coli outer membrane, purified, and characterized biophysically. The OM expressed and purified rMOMP is immunogenic in mice and elicits antibodies that react to the native antigen, Chlamydia elementary body (EB). CONCLUSIONS: C. trachomatis MOMP was functionally expressed on the surface of E. coli outer membrane. The OM expressed and purified rMOMP elicits antibodies that react to the native antigen, Chlamydia EB, in a mouse immunogenicity model. Surface expression of MOMP could provide useful reagents for vaccine research, and the methodology could serve as a platform to produce other outer membrane proteins recombinantly.


Assuntos
Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/imunologia , Vacinas Bacterianas/genética , Vacinas Bacterianas/imunologia , Chlamydia trachomatis/genética , Escherichia coli/genética , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/imunologia , Antígenos de Bactérias/genética , Proteínas da Membrana Bacteriana Externa/biossíntese , Vacinas Bacterianas/biossíntese , Vacinas Bacterianas/química , Células Cultivadas , Infecções por Chlamydia/prevenção & controle , Clonagem Molecular , DNA Bacteriano/genética , Escherichia coli/metabolismo , Feminino , Imunogenicidade da Vacina , Camundongos , Camundongos Endogâmicos C57BL , Modelos Animais , Vacinas de Subunidades Antigênicas/imunologia , Vacinas Sintéticas/biossíntese , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologia
2.
Commun Biol ; 6(1): 649, 2023 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-37337079

RESUMO

Respiratory syncytial virus (RSV) and human metapneumovirus (HMPV) are related RNA viruses responsible for severe respiratory infections and resulting disease in infants, elderly, and immunocompromised adults1-3. Therapeutic small molecule inhibitors that bind to the RSV polymerase and inhibit viral replication are being developed, but their binding sites and molecular mechanisms of action remain largely unknown4. Here we report a conserved allosteric inhibitory site identified on the L polymerase proteins of RSV and HMPV that can be targeted by a dual-specificity, non-nucleoside inhibitor, termed MRK-1. Cryo-EM structures of the inhibitor in complexes with truncated RSV and full-length HMPV polymerase proteins provide a structural understanding of how MRK-1 is active against both viruses. Functional analyses indicate that MRK-1 inhibits conformational changes necessary for the polymerase to engage in RNA synthesis initiation and to transition into an elongation mode. Competition studies reveal that the MRK-1 binding pocket is distinct from that of a capping inhibitor with an overlapping resistance profile, suggesting that the polymerase conformation bound by MRK-1 may be distinct from that involved in mRNA capping. These findings should facilitate optimization of dual RSV and HMPV replication inhibitors and provide insights into the molecular mechanisms underlying their polymerase activities.


Assuntos
Metapneumovirus , Vírus Sincicial Respiratório Humano , Infecções Respiratórias , Lactente , Adulto , Humanos , Idoso , Metapneumovirus/genética , Metapneumovirus/metabolismo , RNA Polimerase Dependente de RNA/genética , RNA Polimerase Dependente de RNA/metabolismo , RNA Mensageiro
3.
NPJ Vaccines ; 4: 24, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31312527

RESUMO

Malaria transmission blocking vaccines (TBV) target the mosquito stage of parasite development by passive immunization of mosquitoes feeding on a vaccinated human. Through uptake of vaccine-induced antibodies in a blood meal, mosquito infection is halted and hence transmission to another human host is blocked. Pfs230 is a gametocyte and gamete surface antigen currently under clinical evaluation as a TBV candidate. We have previously shown that chemical conjugation of poorly immunogenic TBV antigens to Exoprotein A (EPA) can enhance their immunogenicity. Here, we assessed Outer Membrane Protein Complex (OMPC), a membrane vesicle derived from Neisseria meningitidis, as a carrier for Pfs230. We prepared Pfs230-OMPC conjugates with varying levels of antigen load and examined immunogenicity in mice. Chemical conjugation of Pfs230 to OMPC enhanced immunogenicity and functional activity of the Pfs230 antigen, and OMPC conjugates achieved 2-fold to 20-fold higher antibody titers than Pfs230-EPA/AdjuPhos® at different doses. OMPC conjugates were highly immunogenic even at low doses, indicating a dose-sparing effect. EPA conjugates induced an IgG subclass profile biased towards a Th2 response, whereas OMPC conjugates induced a strong Th1-biased immune response with high levels of IgG2, which can benefit Pfs230 antibody functional activity, which depends on complement activation. OMPC is a promising carrier for Pfs230 vaccines.

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