Adjuvant properties and colonization potential of adhering and non‐adhering Lactobacillus spp. following oral administration to mice

This study aimed to determine whether adhesive strains of Lactobacillus possessed an increased ability to colonize the gastrointestinal tract and to examine the adjuvant capacities of these strains for the 50,000 molecular‐mass fragment C of tetanus toxin (TTFC) following oral administration. The three strains used in this study showed different patterns of adhesion to tissue from all regions of the gastrointestinal tract, with two strains adhering in high numbers and one strain showing negligible association with all tissue types. The colonization patterns in the gastrointestinal tract of C57BL/6 mice following oro‐gastric dosing was also monitored, and it was found that adhesive Lactobacillus strains could be detected for at least 24 h, in association with either fecal material and/or with gastrointestinal tissue or contents. In addition, mice were given an oro‐gastric dose of the lactobacilli (5×10 8 colony forming units) with TTFC (10 and 50μg), and the serum‐specific IgM and IgG antibody responses monitored in serum. The adhesive strains, which persisted within the gastrointestinal tract for at least 24 h, showed enhanced antigen‐specific serum IgG and IgM antibody responses in comparison to a non‐adhesive strain that failed to be detected in the gastrointestinal tract. Adhesion to the gastrointestinal tract is a factor affecting the capacity of lactobacilli to persist within the gastrointestinal tract and to act as an adjuvant for orally administered antigen.