Improved immunogenicity of oral D x RRV reassortant rotavirus vaccine by Lactobacillus casei GG

In a search for new strategies to improve oral vaccination, the effect of orally administered Lactobacillus casei strain GG (LGG) in conjunction with D x RRV rhesus-human reassortant live oral rotavirus vaccine was tested in 2–5-month-old infants. Infants who received LGG showed an increased response with regard to rotavirus-specific IgM secreting cells, measured using an ELISPOT technique, on day 8 after vaccination. In infants receiving LGG or placebo, respectively, a rotavirus IgM seroconversion was detected in 2627 (96%) versus 2327 (85%) cases (p=0.15) and rotavirus IgA seroconversion was detected in 2628 (93%) versus 2027 (74%) cases (p=0.05). These findings suggest that LGG has an immunostimulating effect on oral rotavirus vaccination. The clinical significance of LGG-enhanced immune responses to oral vaccines should be further evaluated.