Biologicals : journal of the International Association of Biological Standardization
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Severe fever with thrombocytopenia syndrome (SFTS) is caused by a phlebovirus of the Bunyaviridae family, which is designated as SFTS virus (SFTSV). To our knowledge, no efficient SFTSV vaccine exists. Here, we report the identification of a standard virus strain for the eight major SFTSV strains circulating in China for use in evaluating the SFTSV vaccine. ⋯ In addition, HB29 demonstrated good replication in Vero and MRC-5 cells (8.0 and 6.0 lg 50% cell culture-infectious dose/mL, respectively) and significant CPE, which satisfied the requirements for a standard virus strain. The HB29 isolate was proven identical to the reported HB29 strain by DNA sequencing, and showed high homology in the S segments with other SFTSV strains (94.8-99.7%). Our results suggest that HB29 may be the best candidate standard strain for use in SFTS vaccine development in China.
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Pseudomonas aeruginosa infections are a serious challenge to therapy because of the complex pathogenesis and paucity of new effective antibiotics, thus renewing interest in antibody-based therapeutic strategies. Immunotherapy strategies typically target selected virulence factors that are expressed by the majority of clinical strains of P. aeruginosa, particularly because virulence factors mediate infection. Type a and b flagellins (flagellin a+b) of P. aeruginosa are acute virulence factors that play a major role in the establishment of infection. ⋯ A combination strategy using antibodies against "flagellin a+b" provided greater protection against cell invasion and enhanced opsono-phagocytosis and decreased motility of P. aeruginosa strains, compared to strategies using antibodies against a single flagellin. Antibodies against "flagellin a+b"-protected mice infected with P. aeruginosa strains significantly reduced bacterial dissemination from the site of infection to the liver and spleen. Passive immunization with antibodies against "flagellin a+b" led to an efficacious protection against P. aeruginosa infection in both acute pneumonia and burn models.