Fimbria-specific antibodies in serum and saliva of mice immunized with Actinomyces viscosus T14V fimbriae

Fimbria-specific antibody responses were compared in mice immunized with purified fimbrial adhesins in the region of the submandibular gland (i.e., local site) or at a remote site in the back. One hundred micrograms of fimbriae isolated from Actinomyces viscosus T14V was used as the vaccine. Four subcutaneous injections of the vaccine in the local site induced greater amounts of fimbria-specific immunoglobulin G (IgG) in serum and saliva than three injections. However, there was no difference in the response of fimbria-specific IgA in serum and saliva. Fimbria-specific IgG in serum and saliva were first detected 21 days after the primary immunization at both the local or remote sites. Fimbria-specific IgA in serum was first detected 28 days after the primary immunization at both the local or remote sites. However, fimbria-specific IgA in saliva occurred only in mice immunized with the fimbrial vaccine at the local site and was first detected 14 days after the primary immunization. Both serum and saliva from mice immunized 4 times with the fimbrial vaccine in the local site inhibited in vitro adsorption of strain T14V cells to hydroxyapatite beads pretreated with normal mouse saliva, whereas adsorption of strain T14V cells suspended in serum and saliva from sham-immunized animals was not inhibited. Collectively, these data suggest that mice immunized locally in the submandibular gland region with a vaccine composed of purified fimbrial adhesins provide a potential model for evaluating the efficacy of fimbria-specific antibodies in saliva to inhibit strain T14V colonization of tooth surfaces.