Taishan Pinus massoniana pollen polysaccharide inhibits subgroup J avian leucosis virus infection by directly blocking virus infection and improving immunity

Cuilian Yu,Liping Hu,Yang Li,Mingxu Shao,Hao Zhang,Shifa Yang,Chuanwen Wang,Peng Zhao,Xiuyan Meng,Lijun Zhu,Ruiliang Zhu,Liping Liu,Kai Wei

doi:10.1038/srep44353

Abstract

Subgroup J avian leucosis virus (ALV-J) generally causes neoplastic diseases, immunosuppression and subsequently increases susceptibility to secondary infection in birds. The spread of ALV-J mainly depends on congenital infection and horizontal contact. Although ALV-J infection causes enormous losses yearly in the poultry industry worldwide, effective measures to control ALV-J remain lacking. In this study, we demonstrated that Taishan Pinus massoniana pollen polysaccharide (TPPPS), a natural polysaccharide extracted from Taishan Pinus massoniana pollen, can significantly inhibit ALV-J replication in vitro by blocking viral adsorption to host cells. Electron microscopy and blocking ELISA tests revealed that TPPPS possibly blocks viral adsorption to host cells by interacting with the glycoprotein 85 protein of ALV-J. Furthermore, we artificially established a congenitally ALV-J-infected chicken model to examine the anti-viral effects of TPPPS in vivo. TPPPS significantly inhibited viral shedding and viral loads in immune organs and largely eliminated the immunosuppression caused by congenital ALV-J infection. Additionally, pre-administration of TPPPS obviously reduced the size and delayed the occurrence of tumors induced by acute oncogenic ALV-J infection. This study revealed the prominent effects and feasible mechanisms of TPPPS in inhibiting ALV-J infection, thereby providing a novel prospect to control ALV-J spread.

Highlights

Avian leucosis virus subgroup J (ALV-J) belongs to the genus Alpharetrovirus of the Retroviridae family and generally causes myeloid leucosis, hemangioma, and immunosuppression in broilers and layers[1]
To verify whether Taishan Pinus massoniana pollen polysaccharide (TPPPS) can ameliorate the immune states of congenitally ALV-J-infected chickens, we evaluated the degree of immune organ development, T-lymphocyte counts, lymphocyte proliferations, cytokine secretion, and antibody induction in the ALV-J-infected chickens administered with TPPPS
The present study explored the inhibitory effect and mechanism of a natural plant polysaccharide, TPPPS, on ALV-J infection

Summary

Introduction

Avian leucosis virus subgroup J (ALV-J) belongs to the genus Alpharetrovirus of the Retroviridae family and generally causes myeloid leucosis, hemangioma, and immunosuppression in broilers and layers[1]. Congenital ALV-J infection generally induces innate immune tolerance, which contributes to the latent existence and permanent viral shedding of ALV-J5,6. An effective way to prevent and control ALV-J infection is crucial to reduce the losses caused by ALV-J infection. Whether the whole TPPPS effectively inhibits the infection of ALV-J, which is a more infectious and virulent strain than ALV-B, remains unknown. We examined for the first time the anti-ALV-J activities of TPPPS in cell culture in vitro and investigated the interaction between TPPPS and ALV-J to reveal the probable mechanism that interferes with viral replication. We artificially established a congenitally infected chicken model to simulate the natural infection of ALV-J and assessed the anti-viral effects of TPPPS in vivo. The inhibitory effect of TPPPS on tumor development induced by challenging the chickens with the highly oncogenic strain ALV-J was evaluated

Methods

Results

Conclusion