Effect of anti-thymocyte serum on chronic gingival inflammation in dogs

The role of cellular immunity in chronic gingivitis has been studied in beagle dogs. The mechanism of delayed hypersensitivity in the animals was suppressed by administration of rabbit anti-dog-thymocyte globulin (ATS). The immunosuppressive effect of the antiserum was evaluated from the inhibition of a delayed hypersensitivity reaction in the skin to l-dinitro-2.4-chlorobenzene (DNCB). The level of gingival inflammation was determined before and after antiserum administration by measurements of crevicular leukocytes, gingival fluid and activity of acid phosphatase in crevicular samples.
Antiserum administration inhibited the hypersensitivity reactions in the skin towards DNCB. The gingival parameters were moderately reduced, but similar changes occurred in a group of control dogs injected with normal rabbit immunoglobulin. The results indicate that cellular immunity does not play a major role for the continuous maintenance of chronic gingivitis in the beagle dog.