Xia Xian-zhu

Marburg virus-like particles produced in insect cells induce neutralizing antibodies in rhesus macaques†

Marburg virus (MARV), which is one of the most virulent agents in the world, causes lethal haemorrhagic fever in humans and nonhuman primates (NHPs) with a mortality rate of up to 90%. Currently, there is no effective treatment or approved vaccine for MARV for human use to control disease outbreak and spread. Virus‐like particles (VLPs), which are morphologically identical to the native infectious virus particle, are efficacious as vaccines against many viruses, including human papilloma virus (HPV), porcine circovirus (PCV) type 2 and hepatitis B virus (HBV). In this study, we generated MARV virus‐like particles (VLPs) by co‐expressing a glycoprotein (GP) and matrix protein (VP40) using the baculovirus expression system. Rhesus macaques vaccinated with MARV VLPs mixed with adjuvant Poria cocos polysaccharides (PCP‐II) produced a GP‐specific IgG titer of up to 1:1280 and virus‐neutralizing antibody titers that reached 1:320. MARV VLPs also elicited interferon‐γ (IFN‐γ) and interleukin‐4 (IL‐4) secretion associated with T‐helper 1 cell (Th1)‐ and T‐helper 2 cell (Th2)‐mediated immunity, as detected using enzyme‐linked immunospot (ELISpot) assays. These data indicate that MARV VLPs mixed with adjuvant PCP‐II have excellent immunogenicity in rhesus macaques and may be a promising candidate vaccine against MARV.

Serological survey on canine coronavirus antibodies in giant pandas by virus neutralization test

In order to survey the infectious situation of canine coronavirus (CCV) in giant panda population, a virus neutralization test detecting specific antibodies against CCV in giant panda’s sera was established by using two-fold dilutions of serum and 100 TCID50 of the virus. The 62 sera samples of giant pandas, which were gathered from zoos and reserve region of Sichuan Province, China were detected. The neutralization antibody titer of 1:4 was recognized as the positive criterion, 8 sera samples were detected to be positive, and the positive rate was 12.9%. The titers of neutralizing antibody ranged from 1:8 to 1:32. It was the first comprehensive investigation on neutralization antibodies against CCV in giant panda population in China. The results of study showed that the infection of CCV in giant panda population was universal, which has posed a threat to the health of giant panda. Therefore, it is incumbent on us to study safe and effective vaccines to protect giant panda against CCV infection.