Fig 5. Recombinant S. mitis induces mucosal and systemic antibody responses.

Germ-free Balb/c mice were inoculated orally with 10⁹ cfu rS. mitis expressing HIV Env gp120 (Smitis HIV Env), rS. mitis containing an integrated Erm^r gene without Env gp120 (Smitis), or PBS (Non-Immunized). Following immunization, the presence of IgA, IgG1, and IgG2a antibodies specific to the HIV Env gp120 protein (HIV Ag) or S. mitis lysate antigens (S. mitis Ag) was measured by ELISA in the saliva (A) and serum (B) of mice. The mean optical density (OD) (±SEM) values of the undiluted samples from 3 mice/group at various timepoints post-immunization are shown. The saliva and serum antibody dilution factor was 1:3 or indicated otherwise.