Anti-TGEV Miller Strain Infection Effect of Lactobacillus plantarum Supernatant Based on the JAK-STAT1 Signaling Pathway

Wang, Kai; Ran, Ling; Yan, Tao; Niu, Zheng; Kan, Zifei; Zhang, Yiling; Yang, Yang; Xie, Luyi; Huang, Shilei; Yu, Qiuhan; Wu, Di; Song, Zhenhui

Transmissible gastroenteritis virus (TGEV) is the pathogenic agent of porcine transmissible gastroenteritis (TGE), which causes vomiting, diarrhea, and high mortality in suckling piglets (Masters, 2006) , resulting in heavy losses to the pig breeding industry (Zhao et al., 2014) . In particular, viral diarrhea diseases are more serious because of limited treatment options. Probiotics comprise microorganisms that have beneficial activities to the host, and mainly comprise Clostridium butyricum, Lactobacillus, Bifidobacteria, Actinomycetes, and yeasts. They usually occupy the human gut and reproductive system, and can improve the balance of the host microecology (Fuller, 1989; Maragkoudakis et al., 2010; da Silva Sabo et al., 2017; Stofilova et al., 2017) . There is growing interest in the oral administration of appropriate probiotics to reduce the pressure in the intestines and produce an effective innate immune response (Pollmann et al., 2005; Maragkoudakis et al., 2010) . In recent years, probiotic animal feed supplements have been developed as viable alternatives to antibiotics because of the ban on antibiotics in feed (Scharek et al., 2007) . The addition of probiotic feed can prevent the infection of pathogens causing intestinal diseases, directly benefiting the animal host (Villena et al., 2014) , or can indirectly enhance the host's immune response by balancing the disordered microbiota (Lee et al., 2018) . In addition, many basic and clinical studies have confirmed that probiotic strains have antiviral effects (Lee et al., 2011; Yuan et al., 2018) . Studies have shown that Lactobacillus plantarum can stimulate the body's innate and acquired immunity, and contributes to the production of inflammatory factors that inhibit the replication of the virus in the body. For example, L. plantarum strain YU (LpYU) not only has high interleukin (IL)-12-inducing activity mediated by Tolllike receptor (TLR) 2 in mouse peritoneal macrophages, but also communicates with natural killer cells (NK) in the spleen to stimulate the production of IgA to enhance the body's anti-H1N1 virus activity (Kawashima et al., 2011) . In addition, L. plantarum L-137 can stimulate the production of type I interferon (IFN-1) to effectively inhibit the proliferation of H1N1 (Maeda et al., 2009) . TGEV is an important gastrointestinal diarrhea virus; therefore, research and exploration into the antiviral mechanism of probiotics could lead to the development of oral probiotics to prevent and treat TGEV infection.