抄録
In the present report, phagocytosis-accelerating factor of saliva was investigated with special reference to the serum opsonin and the components of complement. Although the phagocytosis-accelerating activity of saliva appears always lower than that of the serum, it seems to take a part in non-specific resistance to infection of invasive microorganisms in the oral cavity, and may be called saliva opsonin. Even if saliva opsonin is not always identical with serum opsonin because of its lack of C3' or/ and C4', it may consist of a part of serum globulin, or C1' and a minute amount of serum albumin or C2' which enforces the activity of the former. On the other hand, in cases of dental caries, opsonic activity is remarkably decreased in spontaneously secreted saliva, although sucked saliva from the opening of salivary glands retains intact opsonic activity; and the decrease of opsonic activity in carious cases is examined from the distribution of lactobacilli, the supposedly causative agent of the dental caries.
