EVALUATION OF MEBENDAZOLE ACTIVITY ON EXPERIMENTAL MURINE TOXOCARIASIS BY IMMUNE-COMPLEXES DETERMINATION

The mebendazole action on experimental murine toxocariasis, using diff erent formulations and vehicles, was studied by means of the detection of antibodies and immune complexes by ELISA. After inoculation with 1 000 embryonated Toxocara canis eggs, BALB/c mice were submitted to the anthelmintic treatment as follows: group 1 (control without treatment ); group 2 (mebendazole (MBZ), Lomper(R), Steve Laboratories, Barcelon a, Spain, suspended in 1% sodium carboxymethylcellulose (CMC) at a dos e of 100 mg/kg/day); group 3 (MBZ, pure compound suspended in 1% CMC a t a dose of 100 mg/kg/day);group 4 (MBZ, pure compound suspended in wa ter at a dose of 100 mg/kg/day); group 5 (MBZ, pure compound, formulat ed to a solid dispersion at 10% in polyethylene glycol 6000 (PEG) then dissolved in water at a dose of 100 mg/kg/day); group 6 (MBZ, pure co mpound, formulated to a solid dispersion at 10% in PEG then dissolved in water at a dose of 50 mg/kg/day); group 7 (MBZ, pure compound, form ulated to a solid dispersion at 10% in PEG then dissolved in water at a dose of 25 mg/kg/day). The treatments were administered on days 5-7 post-inoculation (p.i.) inclusive. The dynamics of the production of t he specific antibodies for both excretory-secretory (ES) antigen or cr ude extract showed a similar profile as compared to the control group. In groups 2 and 6, from the beginning of the treatment, values of imm une complexes fell rapidly and were undetectable for the remainder of the experiment. Reductions of immune complex levels by the 4th-6th, 2n d-3rd and 2nd-5th weeks p.i. were observed from groups 3, 5 and 7, res pectively. In the other groups, similar profiles as compared to the co ntrol group were observed in the dynamics of the specific immune compl exes. The evaluation of chemotherapy by immunological methods is a val id technique for the efficiency of the treatment without the disadvant ages of larval recovery from several digested tissues. Mebendazole, pu re compound, formulated to a solid dispersion in PEG, then dissolved i n water reduced immune complexes from the beginning of the treatment. The larval immobilization produced by MBZ should entail a reduction in their metabolic activity with a reduction in the production of excret ory-secretory substances which are responsible for the formation of im mune complexes. The rapid clearance of specific immune complexes toget her with a total larvae reduction would explain the decrease in specif ic immune complexes, which detection is a valid technique for monitori ng the efficiency of treatment.