Antinucleolar autoantibody induced in mice by mercuric chloride

Mercuric chloride (MC) was administered to mice subcutaneously 3 times a week for 4 weeks. When inbred BALB/c, CBA/JN, C3H/He, C57BL/6 and DBA/2 and outbred ICR female mice were given 1 mg/kg MC, 8 of 10 ICR mice developed antinucleolar autoantibodies (AnuA) of the IgG class but none of the inbred mice produced AnuA. So the ICR mice were used in the following experiments. In a kinetic study, in which mice were given 1.5 mg/kg MC, the positivities and titers of AnuA increased time-dependently, and were kept at high levels until 8 weeks after the final treatment. The AnuA titers of mice receiving 0.5-2.0 mg/kg increased dose-dependently, while the positivity was similar at all dosages. The antibody titers were higher in mice pretreated with an intramuscular injection of either complete or incomplete Freund's adjuvant. The titer increase was more prominent in mice administered doses lower than 0.5 mg/kg. Neither nude mice nor mice treated with a monoclonal antibody to L3T4 (GK1.5) developed AnuA. These results indicate that the induction of AnuA by MC depend primarily on L3T4-positive T cells.