RESUMEN
Coxsackievirus A16 (CVA16) is one of the major pathogens responsible for human hand, foot, and mouth disease (HFMD), which has threatened the health of young children, particularly in Asia-Pacific nations. Vaccination is an effective strategy for protecting children from CVA16 infection. However, there is currently no licensed CVA16 vaccine for use in humans. In this study, we isolated a high-growth CVA16 virus strain in MRC-5 cells and developed an MRC-5-adapted vaccine candidate strain termed CVA16-393 via two rounds of plaque purification. The CVA16-393 strain was grouped into the B1b subgenotype and grew to a titre of over 107 TCID50/ml in MRC-5 cells. The VP1 gene region of this strain, which contains the major neutralizing epitopes, displayed high stability during serial passages. The inactivated whole-virus vaccine produced by the CVA16-393 strain induced an effective neutralizing antibody response in Meriones unguiculatus (gerbils) after two doses of intraperitoneal inoculation. One week after the booster immunization, the geometric mean titres of the neutralizing antibodies for the 10246, 40812TXT, 11203SD, TJ-224 and CA16-194 strains from different regions of China were 137.8, 97.8, 113.4, 64.1 and 122.3, respectively. A CVA16 vaccine dose above 25 U was also able to provide 100% cross-protection against lethal challenges with these five clinical strains in gerbils. Immunization at a one-week interval could maintain a high level of neutralizing antibody titres for at least 8 weeks. Thus, the vaccine produced by this CVA16-393 strain might be promising.
Asunto(s)
Enterovirus Humano A , Enterovirus , Enfermedad de Boca, Mano y Pie , Vacunas Virales , Animales , Anticuerpos Neutralizantes , Anticuerpos Antivirales , Niño , Preescolar , Enterovirus/genética , Enterovirus Humano A/genética , Gerbillinae , Enfermedad de Boca, Mano y Pie/prevención & control , Humanos , Vacunas de Productos InactivadosRESUMEN
Wheat hybrid necrosis has been genetically characterised for many years, but the specific gene(s) and the protein products involved in the processes remains unknown. In this study, protein expression in the base (B), mid (M) and tip (T) segments of the FL-2 leaves of a necrotic hybrid, PZF1 and its parents, Pan555 and Zheng891, was analysed and compared using a high throughput proteomic approach. Twenty-three protein spots, with significant variations in intensity across the necrotic leaf segments, were analysed by MALDI-TOF-MS, of which, 18 were matched to protein accessions in the NCBI database. Several of these proteins are enzymes involved in the methylation cycle, including AdoHcy hydrolase, AdoMet synthase 3 and methionine synthase 1; AdoHcy hydrolase was downregulated sharply in M and T, and AdoMet synthase 3 and methionine synthase 1 were upregulated gradually from M to T. This result suggests that methylation-associated processes, including epigenetic mechanisms, may play a role in the initiation and development of hybrid necrosis. Several energy cycle-associated proteins and cytoprotective proteins were also differentially expressed across the leaf segments, suggesting their direct association with or possible involvement in the necrotic processes. The significant imbalance of a heat-shock protein, a transposon protein and a RNA- and ssDNA-binding protein also makes these proteins potential molecular components in the necrotic processes.
