Figure 2. Appearance of salivary IgA antibody to indigenous oral flora and antigens of immunization. The appearance of salivary IgA antibody (Ab) to micro-organisms associated with indigenous infection or immunization is indicated by arrows. The percentages of children infected with indigenous oral streptococci (S. mitis, S. salivarius, S. sanguis, S. mutans) are indicated by the bars. Data are summarized from Smith and Taubman, 1992, 1993.