Suppressed immune response to T-cell dependent antigen in chemically sympathectomized mice

Chemical sympathectomy induced by 6-hydroxydopamine (6-OHDA) suppressed the secondary immune response of mice to a T-cell (thymus derived lymphocyte) dependent antigen, sheep red blood cells (SRBC). Treatment with 6-OHDA on the day of the secondary injection of SRBC resulted in depression of hemagglutinin titers to the antigen, while treatment with 6-OHDA on the day of the primary injection of SRBC had no effect upon the secondary response to the antigen. In addition, 6-OHDA treatment did not suppress the primary immune response to a T-cell independent antigen, Escherichia coli lipopolysaccharide (LPS). These results suggest that it is the T-cells which are mainly affected by chemical sympathectomy. Significant non-specific toxicity was not observed with 6-OHDA 100mg/kg, the dose of which suppressed the primary and the secondary immune response to SRBC.