Effect of DTC on Humoral Response of SRBC-Immunized Mice Exposed to Restraint Stress Comparison with Calf Thymus Extract

Abstract

The studies were conducted on Balb/c mice exposed to restraint stress twice for 12 h at 24 h intervals. Some of the experimental mice were immunized i. p. with sheep red blood cells (SRBC). The antigen was injected before the first exposure of the mice to restraint stress or immediately after the second loading was ended. Sodium diethyldithiocarbamate (DTC) at a dose of 20 mg/kg or calf thymus extract (TFX) at a dose of 10 mg/kg were injected i. p. four times at 74 h intervals before or after the exposure to restraint stress.

In our experiment restraint stress drastically reduced the number of thymocytes and splenocytes as well as the weight ratio of the thymus and spleen and the changes sustained for 10 days of the observation. Besides humoral response of the restrained mice to SRBC was deteriorated as the number of plaque forming cells (PFC) and anti-SRBC antibody titers (total and 2-mercaptoethanol resistant) decreased. The suppressive action of the stress on humoral response was weaker when the antigen injection preceded the first exposure of mice to restraint stress as compared with that observed when antigen stimulation took place immediately after the exposure of mice to stress.

It has been found that DTC and TFX administered to mice either before or after the exposure to restraint stress effectively inhibit stress-induced immunosupression. The protective or immunomodulating action of the two drugs is expressed in accelerated and enhanced recovery of the spleen and thymus and in total or partial restoration of the humoral response to thymus-dependent antigen. TFX administered after the exposure of mice to restraint stress proves to have a stronger protective and reconstructive impact on thymus while DTC has a stronger restoring effect on the humoral response dependent on effector T lymphocytes. DTC administered immediately after the exposure of mice to restraint stress results in total restoration of humoral response to SRBC.