Table 2.

Efficacy of microflora modulation in in vivo models of multiple sclerosis

Species and Strain of Laboratory Animals	Model		Intervention		Main Findings	Refs.
Lactobacilli
C57BL/6 mice	EAE (immunization with a synthetic peptide from myelin oligodendrocyte glycoprotein in CFA, administration of pertussis toxin)		Lactobacillus paracasei and L. plantarum in a therapeutic regimen or before and after immunization		Delayed progression and reversal of the clinical and histological signs of the disease. The mechanism is associated with attenuation of pro-inflammatory Th1 and Th17 cytokines followed by IL-10 induction in MLNs, spleen, and blood. Monotherapy with the strains used in the study appeared to be inefficient.	[70, 115, 116]
C57BL/6 Mice	EAE (MOG35-55)1		Lactobacilli (three strains, L. paracasei DSM 13434, L. plantarum DSM 15312 and DSM 15313) before and after induction of the model		Reduction of clinical and histological signs of the disease, that correlated with attenuation of pro-inflammatory Th1 and Th17 cytokines followed by IL-10 induction in MLNs, spleen, and blood. Monotherapy with the strains used in the study appeared to be inefficient.	[73, 116]
SJL/J mice	EAE (PLP139-151)2		Lactobacillus helveticus SBT2171 intraperitoneally before and after induction of the model		A significant decrease in the incidence and clinical signs, reduction in the quantity of Th17 cells in the spinal cord associated with downregulation of IL-6 production and the subsequent Th17 differentiation and spinal cord infiltration.	[117]
Lewis rat	Immunization with MBP72-85 in Difco’s incomplete adjuvant		Lactobacillus casei 393, or commercially available products containing Lactobacillus casei DN 114-001 or Lactobacillus rhamnosus or Lactobacillus casei given orally seven times during a 44-day experiment		In all cases, the total disease burden was reduced (27—63%), maximal disease score and time of onset (but not the duration of disease) were decreased. Most notably, in the other experiments on SJL/J mice, no efficacy was seen in any of the lactobacilli preparations.	[73, 118]
SJL/J and C57BL/6 Mice	EAE (PLP139-151) 2 in SJL/J mice and EAE (MOG35-55) 1 in C57BL/6 mice		Lactobacillus casei strain Shirota before and after induction of the model		Absence of exacerbation of neurological symptoms, tendency towards improvement of neurological symptoms in the SJL/J mouse. Enhanced production of IL-10 and an increase in the percentage of CD4(+) CD25(+) T regulatory cells. Transient upregulation of IL-17 production by antigen-stimulated lymphocytes, confirming that IL-17 responses at peripheral sites may not always result in a worsening of autoimmune diseases.	[114]
C57BL/6 mice	EAE (MOG35-55) 1		Lactobacillus reuteri DSM 17938 before and after immunization		Reduction of TH1/TH17 cells and their associated cytokines IFN-γ/IL-17, restoration of the diversity of gut microbiota.	[119]
C57BL/6 mice	Cuprizone-induced model		Lactobacillus casei strain T2 (IBRC-M10783), oral administration of 1 × 109 CFU/ml probiotic for 4 weeks before or after induction of the model, the combined treatment with vitamin D (20 IU/day) after induction of the model was also evaluated.		Improvement of the motor behaviors in the Y-maze test (all regimens of treatment), decrease in IL-17 serum level (especially after the combined treatment), reversal of cuprizone-induced IDO gene expression and miR-155 expression, reversal of the decrease in miR-25 expression. It is supposed that the probiotic it seems that can shift responses from Th17 to Tregs and play a role in the recovery of demyelination processes.	[120]
Lewis rats	Immunization with guinea pig myelin basic protein with CFA		Lactobacillus casei Shirota started at the age of 2 weeks, induction of the model at the age of 7 weeks		Increased the duration of clinical symptoms, adjuvation is supposed for both Th1 and Th2 responses.	[73, 121]
Species and Strain of Laboratory Animals	Model		Intervention		Main Findings	Refs.
Lactococcus
C57BL/6 mice	EAE (MOG35-55) 1		Recombinant Lactococcus lactis strain that produces and releases LPS-free Hsp65 orally in a prophylactic regimen		Decrease in inflammatory cell infiltration and injury signs in the spinal cord associated with reduced IL-17 and increased IL-10 production in mesenteric lymph nodes and spleen. The significant increase in the number of natural and inducible CD4+Foxp3+ regulatory T (Treg) cells and CD4+LAP+ Tregs expressing the membrane-bound TGF-β - in spleen, inguinal and mesenteric lymph nodes, and spinal cord.	[73, 122]
Bifidobacteria
Lewis rats (LEW/HanHsD)	Immunization with guinea pig myelin basic protein (MBP) with CFA		Bifidobacterium animalis started at the age of 2 weeks, induction of the model at the age of 7 weeks		Significant reduction in the duration of clinical symptoms, normalization of body weight dynamics.	[73, 121]
Bacteroides fragilis
SJL/J mice	EAE (PLP139-151) 2		Bacteroides fragilis producing a bacterial capsular polysaccharide Ag (decolonization after the destruction of gut bacteria with a combination of antibiotics)		Resistance to the development of the disease with protection against CNS demyelination. Activated rates of conversion of CD4+ T cells into IL-10- producing Foxp3+ Treg cells, thus shifting the balance towards the anti-inflammatory cytokines.	[73, 123]
C57BL/6 mice	EAE (MOG35-55) 1		Zwitterionic capsular polysaccharide A of Bacteroides fragilis before and after induction of the model		Delayed onset and progression of the disease, enhanced levels of anti-inflammatory cytokines. The mechanism of action is associated with the expansion of CD4 T cells.	[73, 124, 125]
Pediococcus acidilactici
C57BL/6 mice	EAE (MOG35-55) 1		Pediococcus acidilactici R037 (heat-killed) from 14 days before immunization		Decreased severity of the disease, inhibition of the antigen-specific production of inflammatory cytokines associated with primary induction of Foxp3(-) IL10-producing T regulatory type 1 (Tr1) cells in mesenteric lymph nodes.	[73, 126]
Escherichia coli strain Nissle
C57/BL6J mice	EAE (MOG35-55) 1		Escherichia coli strain Nissle 1917		Reduction in the severity of the disease, suppression of secretion of inflammatory cytokines and an activated production of the anti-inflammatory cytokine IL-10 by autoreactive CD4 T cells, both in peripheral lymph nodes and CNS. Modulation of activation and/or differentiation of T cells, thus influencing their migration from the periphery to the CNS is supposed.	[127]
SJL or C57BL / 6 mice	EAE (MOG35-55) 1 or EAE (PLP139-151) 2		Zwitterionic capsular polysaccharide A of Bacteroides fragilis in prophylactic or therapeutic regimen		Reduction in the severity of the disease, the increase in CD103 expressing dendritic cells that accumulated in the cervical lymph nodes. The mechanism is attributed to the enhancement in the conversion of CD4+ T cells into IL-10- producing Foxp3+ Treg cells.	[73, 128]
Prevotella histicola
HLA-DR3.DQ8 double-transgenic mice lacking MHC class II genes	Immunization with PLP91-110		Prevotella histicola starting 7 days after immunization, 7 doses on alternate days		Decrease in pro-inflammatory Th1 and Th17 cells and increase in the frequencies of CD4+FoxP3+ regulatory T cells, tolerogenic dendritic cells, and suppressive macrophages substantiating the favorable modulation of systemic immune responses.	[73, 129]
Species and Strain of Laboratory Animals	Model	Intervention		Main Findings			Refs.
Combined probiotics
C57BL/6 mice	EAE (MOG35-55) 1	IRT5 containing Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus reuteri, Bifidobacterium bifidum, and Streptococcus thermophilus in a prophylactic regimen		Delayed onset and less severe course of the disease, inhibition of the pro-inflammatory Th1/Th17 polarization, while inducing IL10+ producing or/and Foxp3+ regulatory T cells, both in the peripheral immune system and at the site of inflammation.			[70, 115, 130]
C57BL/6 mice	EAE (MOG35-55) 1	Lactobacillus plantarum A7, Bifidobacterium animalis PTCC 1631or a mixture of both strains orally daily for 22 days beginning simultaneously with induction of the disease		Delay in the time of disease onset, decrease in mononuclear infiltration into the CNS, enhancement of the population of CD4+CD25+Foxp3+-expressing T-cells in the lymph nodes and the spleen. These effects were more significant when the combination of both strains was used. The inhibition of the disease associated cytokines and increment in anti-inflammatory cytokines, favoring Th2 and Treg differentiation via up-regulation of Foxp3 and GATA3 in the brain and spleen, inhibition of the differentiation of Th1 and Th17 cells.			[131]
Lewis rats	Immunization with guinea pig MBP or other antigens	Lactobacillus casei strain Shirota and Bifidobacterium breve strain Yakult before and after induction of the model in different regimens		Absence of autoimmune disease exacerbation after the use of both strains, in one of the regimens - tendency to suppression of neurological symptoms.			[114]
Additional data obtained using vaccination approaches
SJL mice	EAE (PLP139-151) 2	Vaccination with Salmonella expressing E. coli colonization factor antigen I fimbriae, with further transfer of isolated CD25+ and CD25−CD4+ T cells to naive mice		Reduced development and progression of the disease, suppression of the development and expansion of Th1 and Th17 cells, normalization of cytokine balance. It was ascertained that CFA/I fimbriae offer an alternative strategy to adapt Treg cells and modulate the expansion of myelin specific Treg cells to suppress autoimmune disease.			[73, 132, 133]
SJL/J mice	EAE (PLP139-151) 2	Vaccination with Salmonella-CFA/I vaccine expressing functional CFA/I fimbriae from Escherichia coli in a therapeutic regimen.		Reduction in disease severity and duration, enhanced production of TGF-β, (not IL-10), the optimal induction of the protective T(reg) cells in conjunction with immune deviation by Th2 cells.			[73, 134]

¹EAE (MOG_35-55) - experimental autoimmune encephalomyelitis induced by immunization with MOG_35-55 peptide in CFA and administration of Pertussis toxin. ²EAE (PLP_139-151) - experimental autoimmune encephalomyelitis induced by immunization with PLP_139-151 peptide in CFA and administration of Pertussis toxin.