3.1.1. Effects on Level of Interleukins
Oral Lactobacillus casei ATCC 39392 vaccine polarized Th2 cell immunity and stimulated IL-17 expression against transmissible gastroenteritis coronavirus (TGEV) (Xinpeng Jiang et al., 2016), however, an anti interleukin (IL)-17 effect was observed forBifidobacterium animalis (Hüseyin Sancar Bozkurt & Quigley, 2019). In another study, the probiotic strain “heat-killed Lactobacillus plantarum L-137 ” was introduced as an IL-12 inducer in mice (Murosaki et al., 1998).
In a trial conducted by kimmel et al, 10 healthy Subjects consumed 1 capsule/day of Bacillus coagulans GBI-30, 6086 (GanedenBC30) for 28 days and returned for post-treatment immunological markers evaluation; IL-6, IL-8, and TNF-alpha levels were increased after exposure to a strain of adenovirus (AdenoVI) and influenza A (H3N2 Texas strain; FluTex). IL-1beta levels also increased after exposure to AdenoVI but were reduced after ex vivo exposure to FluTex (Kimmel, Keller, Farmer, & Warrino, 2010).
Some hypotheses indicated that oral administration of theStreptococcus salivarius  K12 strain, through a still not perfectly clear molecular mechanism, reduced IL-8 plasma concentrations and increased salivary interferon-γ. These modulations may also realistically account for anti-inflammatory and antiviral activity, which would then be added to the antibacterial action of the K12 strain (Wescombe, Hale, Heng, & Tagg, 2012).
Coronaviruses may also vulnerable to probiotics. Chi et al. after infecting swine testicle (ST) cells with TGEV administeredEnterococcus faecium NCIMB 10415 ; as a result, production of nitric oxide increased and expression of IL-6 & 8 in the cells treated with E. faecium was elevated (Chai et al., 2013). Another research claimed that Enterococcus faecium HDRsEf1 could significantly downregulate the mRNA level of pro-inflammatory factors IL-1ß, IL-6, IL-8, IL-12, IL-17, and TNF-a (Tian et al., 2016).