Proliferation Characteristics of Coxsackievirus A10 in Mice and Immune Protection of Experimentally Inactivated Vaccine

Abstract

Background: Coxsackievirus A10 (CVA10) is a causative agent of hand, foot, and mouth disease and is the main pathogen of this disease in China. However, there are no CVA10-specific drugs and vaccines, and the pathogenesis and effects of this virus in the body are unknown. Methods: We investigated the effect of a clinically isolated CVA10 virus strain (CVA10-25) to investigate its effect on suckling mice through different infection routes. We observed the dynamic distribution and proliferation of the virus in mouse tissues by inoculating suckling mice with different doses and by infecting mice of different ages with the same dose; we also analysed the pathological characteristics after infection. A formaldehyde-inactivated experimental vaccine was prepared to immunise 5-week-old BALB/c female mice three times, and new-born suckling mice were tested for the presence of maternally transmitted antibodies. Findings: The viral load of each organ following intracerebral administration was higher than that by the intraperitoneal administration; the peroral administration route did not cause disease in mice. Mouse paralysis and death after infection were related to age. The skeletal muscles, heart, and lung showed histopathological changes after infection. We established a 2-day-old BALB/c suckling mouse model that could be infected intracranially to study the pathogenesis and pathology of CVA10. Maternally transmitted antibodies protected against the virus. Interpretation: This study provides a reference for CVA10-related pathogenesis and vaccine research. Funding Information: This project was supported by Yunnan Important New Product Development Plan (2015 BC008) and Medical and Health Science and Technology Innovation Project of Chinese Academy of Medical Science (2016-I2M-1-019). Declaration of Interests: Written consent was obtained from all the participants to publish their data. Authors declare that they have no competing interests. Ethics Approval Statement: The experimental protocols for animals were approved by the Experimental Animal Management Ethics Committee of Institute of Medical Biology, Chinese Academy of Medical Sciences (IMBCAMS), and the experimental animals were specific pathogen-free (SPF) BALB/c mice (Certificate number: SCXK (Dian) K2014-0002; Animal ethics approval number: DWSP201905015).