200 mg daily, 400 mg daily and 200 mg twice daily for 4 weeks

Canine whole blood was collected in sodium heparin tubes from 29 beagle dogs and 23 mixed breed dogs. Whole blood (20 μL) was plated in 96-well plates (Costar 3598) with 180 μL of medium (RPMI 1640, Gibco #21870-076, with 1% heat inactivated fetal bovine serum, Gibco #10082-39, 292 μg/ml L-glutamine, Gibco #250030-081, 100 u/ml penicillin and 100μg streptomycin per ml, Gi bco #15 140- 122) containing vehicle control or test compound (0.001 to 10 μΜ), concanavalin A (ConA; 1 μg/ml, Sigma C5275), and canine inter-leukin-2 (IL-2 ; 50 ng/ml , R&D Systems 1815-CL/CF). Wells containing whole blood, medium with vehicle control and no ConA or I L-2 were used as background controls. Plates were incubated at 37° C for 48 hours. Tritiated thymidine, 0.4 μα/well (Perkin Elmer, Net027A-005 MC), was added for 20 additional hours. Plates were frozen and then thawed, washed and filtered using a Brandel MLR-96 cell harvester and pre-wet filter mats (Wallac 1205-401, Perkin Elmer). Filters were d ried at 60° C for one hour (Precision 16EG convection oven) and placed into filter sample bags (Wallac 1205-411, Perkin Elmer) with 10 mL of scintillant (Wallac 1205-440, Perkin Elmer). Sealed filters were counted on a LKB Wallac 1205 Betaplate liquid scintillation counter.