Oral colonization and immune responses to Streptococcus gordonii expressing a pertussis toxin S1 fragment in mice

摘要

The ability of a recombinant Streptococcus gordonii RJM4 expressing the N-terminal 179-amino acid fragment of S1 subunit of pertussis toxin (PT) as a SpaP/S1 fusion protein was tested for oral colonization and immunogenicity in BALB/c mice. Following two consecutive oral inoculations, 100% of the mice were colonized by the recombinant strains for up to 9 weeks and > 60% of the animals still retained the strains after 19 weeks. RJM4 recovered from the animals continued to express the SpaP/S1 fusion protein indicating the stability of the fusion gene in vivo. Secretory (S) IgA antibody against PT could be detected in saliva from RJM4-colonized mice but not from the control groups of mice. SI.-A against SpaP was also detected in saliva from the RJM4-inoculated and the S. gordonii SL3 (control)-inoculated mice. Serum antibodies against PT and SpaP were not detected in these animals. In conclusion, long-term oral colonization of BALB/c mice with our recombinant S. gordonii was established and the colonization elicited mucosal antibodies against PT and SpaP. (C) 2002 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved. [References: 15]