Effect of anti-thymocyte serum on development of gingivitis in dogs

The effect of repeated injections of heterologous anti-thymocyte globulin (ATS) on the development of gingivitis has been studied in beagle dogs. Control dogs were injected with control rabbit immunoglobulin. The immunosuppressive effect of the antiserum was evaluated from the inhibition of a delayed hypersensitivity reaction in the skin towards l-dinitro-2.4-chlorobenzene (DNCB). The gingival condition was determined by measurements of crevicular leukocytes, gingival fluid, acid phosphatase activity in crevicular samples and by counts of inflammatory cells in sections of gingival biopsies. Antiserum administration, but not control rabbit IgG, abolished the hypersensitivity reaction in the skin towards DNCB. The parameters of gingival inflammation increased during the 28day experimental period, both in the experimental and in the control dogs. The results indicate that cellular immunity does not play a major role for the development of gingival inflammation in beagle dogs.