# The Antiviral Potential of Probiotics--A Review on Scientific Outcomes
## 3 In Vivo Evidence of the Antiviral Activities of Probiotics  
The pre-exposure of probiotictic strain _Lactobacillus rhamns_ GG could improve the host's cell mediated-immune system against the H1N1 influenza virus. Specifically, the intranasal intervention of _L. rhamn_sog for three days induced pulmonary YAC-1 cell-killing activity and the transcriptional expression of pulmonary IL-1\(\beta\) and TNF in BALB\(\gamma\)c mice, which suggests that probiotictic supplementation could protect the host system via a cell-mediated immune response [34]. The BALB/c mice were orally supplemented with _L. rhamns_ GG and _Lactobacillus tgasseri_ TMC0356 for nineteen days, and the animals were exposed to influenza virus (5 \(\times\) 10\({}^{6}\) PFU per mouse) on day 14. The mice administered with _L. rhamn_sog and _L. gasseri_ TMC0356 showed a significant reduction in clinical symptoms and viral titer compared to the control group [35]. [PERSON] et al. [36] determined the antiviral effect of _Lactobacillus plantarum_ (DK119) isolated from the fermented Korean vegetable food \"Kimchi\". The intranasal or oral administration of _L. plantarum_ (DK119) provided greater protection against influenza virus infection in mice. A few years later, another crew of researchers studied the protective anti-viral effect of heat-killed cells of _L. plantarum_ (Lp) isolated from Kimchi. In this study, the crew found that the oral intake of heat-killed _Lp_ (named nF1) could protect mice from the lethal challenges caused by different influenza strains, such as Influenza A and Influenza B, which was detected by determining the number of survival days of the infected mouse. Their observations are reliable that the heat-killed _Lp_ (nF1) treatment significantly reduced viral \begin{table}
\begin{tabular}{c c c c c} \hline
**Probiotic(s)** & **Model** & **Anti-Viral** & **Findings** & **Ref.** \\ \hline _B. longum_ BORI & MA104 cells & Rotavirus & Inhibit the viral infection & [32] \\ \hline _Lactobacillus rhamns_ GG and & Human and animal & Rotavirus & \(\uparrow\) Release of ROS. Attachment to cell & \\ _L. casei_ Shirota & epithelial cell lines & Transmissible & line was varied. & [33] \\  & & gastroenteritis virus & \(\uparrow\) The integrity of the monolayer. & \\ \hline \end{tabular} \(\uparrow\): Increased, \(\downarrow\): Reduced; ROS: reactive oxygen species; NO\(\gamma\)s. Noroviruses; VLPs: Human NoV virus-like particles.  
\end{table} 
Table 1: \(Cont.\)load and replication in infected mouse lungs [37]. Altogether, these results recommend the remedial potential of heat-killed _Lp_ against influenza. Thus far, influenza has been an acute fatal respiratory tract infection all over the world. Both younger and elderly individuals are equally prone to risk their lives, despite their feeble immune function. The vaccination for influenza does not provide much prevention because of the peculiar development of their resistive nature and concurrent mutagenesis, which could deliberately change the dominant viral strains. Hence, it is important to initiate convincible new natural alternative defensive procedures in the host system by triggering innate immunity in day-to-day life. The yogurt fermented with _Lactobacillus delbrueckii_ ssp. _bulgaricus_ OLL1073R-1 was found to reduce the risk of catching a cold [38]. The probiotic yogurt was orally administered in the quantity of 0.4 mL/day, and the Exopolysaccharides (EPS) isolated from 1073R-1 were also given (20 ug of EPS/day) to BALB/c mice for 21 days before intranasal infusion with influenza virus A/PR/8/34 (H1 NI). The anti-influenza virus effects of both yogurt and EPS were exerted by the immunostimulatory effects and NK cell activity in the mice [39]. Some of the species of LAB, such as _L. plantarum_ YU [40] and _Lactobacillus casei_ [PERSON] [41; 42], have been already testified to have potent anti-influenza virus properties in mice. _Lactobacillus brevis_ KB290 (KB290), isolated from a traditional Japanese pickle \"Suguki\", has immunomodulatory effects.