SARS Coronavirus Fusion Peptide-Derived Sequence Suppresses Collagen-Induced Arthritis in DBA/1J Mice

Shen, Zu T.; Sigalov, Alexander B.

Male 6-7 week old DBA/1 mice from Harlan (Indianapolis, IN) were anaesthetized with Isoflurane (VetOne, Boise, ID) and injected intradermally with 100 μ L of Freund's Complete Adjuvant (Sigma Aldrich Company, St. Louis, MO) (2.5 mg/ml final concentration) containing bovine type II collagen (Bolder BioPATH, Boulder, CO) (2 mg/ml final concentration) at the base of the tail on day 0 and again on day 21. On day 24, mice were randomized by body weight into treatment groups. Mice weighed approximately 17-25 grams (mean 20 g) at enrollment on day 24 when treatment was initiated. Mice were i.p. injected with 25 mg/kg/day MG11 or MG11-2G, or 2.5 mg/kg/day MG11-sHDL, or with PBS for 14 days beginning at day 24. Arthritis onset occurred on days 26-38. Mice were weighed on study days 24, 26, 28, 30, 32, 34, 36 and 38 (prior to necropsy) . Daily clinical scores were given on a scale of 0-5 for each of the paws (right front, left front, right rear, left rear) on days 24-38 using the following criteria: 0 = normal; 1 = one hind or fore paw joint affected or minimal diffuse erythema and swelling; 2 = two hind or fore paw joints affected or mild diffuse erythema and swelling; 3 = three hind or fore paw joints affected or moderate diffuse erythema and swelling; 4 = four hind or fore paw joints affected or marked diffuse erythema and swelling; 5 = entire paw affected, severe diffuse erythema and severe swelling, unable to flex digits. On day 38, mice were humanely euthanized for necropsy. Mice were anesthetized with Isoflurane and bled by cardiac puncture. Serum was prepared and stored frozen at − 80 °C for cytokine analysis.