We studied the inhibitory effects of passive immunization with antibody against Streptococcus mutans surface protein antigen I/II (SAI/II) on experimental dental caries in rats and humans was investigated. The results obtained were as follows. Two groups of rats were infected with S. mutans (c) and fed a modified diet 2000 which contained 50% sucrose and 6% lyophilized normal rabbit serum or 6% lyophilized anti-SAI/II rabbit serum. A significantly lower caries score was observed in rats fed the modified diet 2000 containing anti-SAI/II serum powder as compared with the control rats. In the intraoral cariogenicity test experiment in humans, the enamel slabs set on both sides of the device were immersed in 3% sucrose solution for 10min. outside the mouth. One side of the enamel was treated with normal rabbit serum and the other side was treated with anti-SAI/II rabbit serum, 3 times daily for 2 weeks. The enamel treated with sucrose plus anti-SAI/II serum showed statistically significant lower demineralization, than the enamel treated with sucrose plus normal serum.
