Human cytomegalovirus infects the majority of humanity which may lead to severe morbidity and mortality in newborns and immunocompromised adults. Humoral and cellular immunity are critical for controlling CMV infection. HCMV envelope glycoprotein complexes (gC I, II, III) represent major antigenic targets of antiviral immune responses. The gCIII complex is comprised of three glycoproteins, gH, gL, and gO. In the present study, DNA vaccines expressing the murine cytomegalovirus homologs of the gH, gL, and gO proteins were evaluated for protection against lethal MCMV infection in the mouse model. The results demonstrated that gH, gL, or gO single gene immunization could not yet offer good protection, whereas co-vaccination strategy apparently showed effects superior to separate immunization. Twice immunization with gH/gL/gO pDNAs could provide mice complete protection against lethal salivary gland-derived MCMV (SG-MCMV) challenge, while thrice immunization with pgH/pgL, pgH/pgO or pgL/pgO could not provide full protection. Co-vaccination with gH, gL and gO pDNAs elicited robust neutralizing antibody and cellular immune responses. Moreover, full protection was also achieved by simply passive immunization with anti-gH/gL/gO sera. These data demonstrated that gCIII complex antigens had fine immunogenicity and might be a promising candidate for the development of HCMV vaccines.
The aim of this study is to investigate the long-term immunogenicity of inactivated split-virion 2009 pandemic influenza A H1N1 vaccine after a single immunization. We recruited 480 adults, aged 18-60 years, for a placebo-controlled, observer-masked, single-center clinical study. We randomly assigned subjects into four groups: 15 μg, 30 μg and 45 μg of hemagglutinin (HA) dosage groups, and a placebo control group. Finally, 259 subjects completed the entire study. The rates of seroconversion and seroprotection and the geometric mean increase (GMI) fulfilled the criteria of the European Medicines Agency (EMEA) for influenza vaccine for 180 days after vaccination in all three dosage groups. However, the seroprotection rates of all dosage groups were below 70% at day 360 post vaccination, while the seroconversion rates and the GMI continued to meet the licensure criteria at this time point. In conclusion, a single dose of 15 μg HA vaccine could induce a protective immune response persisting for at least six months in adults. This study could be beneficial for the future development of influenza vaccines conferring long-term immunity.
COVID-19 pandemic caused by SARS-CoV-2 infection has an impact on global public health and social economy. The emerging immune escape of SARS-CoV-2 variants pose great challenges to the development of vaccines based on original strains. The development of second-generation COVID-19 vaccines to induce immune responses with broad-spectrum protective effects is a matter of great urgency. Here, a prefusion-stabilized spike (S) trimer protein based on B.1.351 variant was expressed and prepared with CpG7909/aluminum hydroxide dual adjuvant to investigate the immunogenicity in mice. The results showed that the candidate vaccine could induce a significant receptor binding domain-specific antibody response and a substantial interferon-γ-mediated immune response. Furthermore, the candidate vaccine also elicited robust cross-neutralization against the pseudoviruses of the original strain, Beta variant, Delta variant and Omicron variant. The vaccine strategy of S-trimer protein formulated with CpG7909/aluminum hydroxide dual adjuvant may be considered a means to increase vaccine effectiveness against future variants.
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