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) 18, however, an anti interleukin (IL)-17 effect was observed for Bifidobacterium animalis 19. In another study, the probiotic strain “heat-killed Lactobacillus plantarum L-137 ” was introduced as an IL-12 inducer in mice 20.
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 21.
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 strain22.
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 23. 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 24.