vi sinh vật của một con người trưởng thành thiếu khả năng bổ trợ để kích thích phản ứng antirotavirus sIgA chuột gnotobiotic nhưng, ngược lại, gây tác dụng ức chế như E. coli (Bảng 2) (79). Vì vậy, hiệu ứng điều chỉnh của Bifidobacterium là straindependent, | Immune Modulation by the Intestinal Microbiota 109 Table 2 The Gut Colonization of Different Bacterial Strains Modulates the Intestinal Anti-rotavirus IgA Antibody Response Measured in Gnotobiotic Mice Intestinal microflora of gnotobiotic mice Anti-rotavirus sIgA antibody level AU g of feces Bifidobacterium bifidum from baby Bifidobacterium DN 173 010 a commercial strain Germ-free control Bifidobacterium infantisCB. pseudocatenulatumC B. angulatumC B. sp from human adult E. coli from infants or Bacteroides vulgatus from human adult 31 7a 21 3a 11 2 4 1aY 4 1aY a Significant difference with germ-free mice p . Abbreviation AU arbitrary units. Source From Refs. 72 79. microbiota of an adult human lacked the adjuvant ability to stimulate the sIgA antirotavirus response in gnotobiotic mice but on the contrary exerted a suppressive effect as do E. coli Table 2 79 . Thus the modulating effect of Bifidobacterium is straindependent as it has also been described for different Lactobacillus strains used as probiotics in other mice studies 80 . Taken together these data suggest that it is important to define the modulatory effect of the strains of bifidobacteria either normally colonizing the digestive tract of babies after birth or given as probiotics to modulate in a good protective way a specific intestinal immune response. In conclusion and on the basis of the experimental and clinical data we may consider that the presence of certain bacterial strains in the infantile intestinal microbiota namely some strains of Bifidobacterium or some transiting strains of probiotics enable activation of the mechanisms that result in optimization of the anti-rotavirus protective IgA Ab response. Elucidation of the immunomodulatory mechanisms must now be pursued. Regulation of the Immune Responses Tolerance to Soluble Proteins Oral Tolerance The role of the intestinal microbiota on the OT process has been demonstrated by various experimental studies using GF mice. Results depend on .
