Identification of a candidate standard strain of severe fever with thrombocytopenia syndrome virus for vaccine quality control in China using a cross-neutralization assay.
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. Rabbits were immunized with the SFTSV strains and the cross-neutralization capacities of SFTSV anti-sera were determined in microculture cytopathic effect (CPE)-inhibition assays. The mean cross-neutralization capacity of the eight SFTSV anti-sera ranged from 62.4 to 142.6%, compared to autologous strains. The HB29 strain demonstrated strong cross-reactivity with heterologous antibodies, and 33 serum samples from SFTS patients efficiently neutralized HB29, suggesting its broad cross-reactivity. 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.
National Institutes for Food and Drug Control, Beijing 100050, PR China.
Zheng
Z
Jia
National Institutes for Food and Drug Control, Beijing 100050, PR China.
Xiaohong
X
Wu
National Institutes for Food and Drug Control, Beijing 100050, PR China.
Ling
L
Wang
Beijing Institute of Biological Products Co., Ltd., Beijing 101111, PR China.
Xiuling
X
Li
Beijing Institute of Biological Products Co., Ltd., Beijing 101111, PR China.
Xinxian
X
Dai
Key Laboratory for Medical Virology, NHFPC, National Institute for Viral Disease Control and Prevention, China CDC, Beijing 102206, PR China.
Mifang
M
Liang
National Institutes for Food and Drug Control, Beijing 100050, PR China.
Shouchun
S
Cao
National Institutes for Food and Drug Control, Beijing 100050, PR China.
Yan
Y
Kong
National Institutes for Food and Drug Control, Beijing 100050, PR China.
Jingjing
J
Liu
National Institutes for Food and Drug Control, Beijing 100050, PR China. Electronic address: lyhchengdu@sina.com.
Yuhua
Y
Li
National Institutes for Food and Drug Control, Beijing 100050, PR China. Electronic address: wangjz@nifdc.org.cn.
Junzhi
J
Wang
D000595:Amino Acid Sequence; D000818:Animals; D044466:Asian People; D002044:Bunyaviridae Infections / Q000208:ethnology / Q000276:immunology* / Q000821:virology; D002460:Cell Line; D002681:China; D002522:Chlorocebus aethiops; D003429:Cross Reactions / Q000276:immunology; D054884:Host-Pathogen Interactions / Q000276:immunology; D006801:Humans; D009500:Neutralization Tests / Q000379:methods*; D016856:Phlebovirus / Q000235:genetics / Q000276:immunology* / Q000502:physiology; D010802:Phylogeny; D011786:Quality Control; D011817:Rabbits; D012015:Reference Standards; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014709:Vero Cells; D014759:Viral Envelope Proteins / Q000145:classification / Q000235:genetics; D014765:Viral Vaccines / Q000276:immunology* / Q000592:standards
D014759:Viral Envelope Proteins; D014765:Viral Vaccines
CPE; NTAbs; Neutralizing antibodies; SFTS; SFTS virus; SFTSV; Severe fever with thrombocytopenia syndrome virus; Standard viral strain; Vaccine; cytopathic effect; neutralizing antibodies; severe fever with thrombocytopenia syndrome