Preparation of F(ab’)2 antivenom in Iraq against scorpion (Hottentotta saulcyi) venom

The aim of this study was to prepare specific F(ab’)2 antivenom against Iraqi scorpion (Hottentotta saulcyi). Venom was obtained by electrical stimulation method, the scorpions venom storage capacity was 1.7 ± 0.4 mg and LD50 found to be 1.07 mg/kg by subcutaneous (s.c) route. Three local horses aging 3–4 years were selected for immunization. During the schedule each horse received 0.5–14 mg venom in 49 days by s.c route. The horses immune response was monitored by Ouchterlony double immunodiffusion method, however, older horse A showed the highest antibody titer (1:1056576). Hyperimmune plasma was purified by modified World Health Organization (WHO) protocol using pepsin and ammonium sulfate, whereas high purity and total removal of albumin was detected by serum protein electrophoresis (SPEP) method on cellulose acetate. ED50 of the antivenom was determined via s.c route and found to be 83 LD50/ml, neutralizing 1.78 mg (venom)/ml (antivenom). Protein concentration of the antivenom was 30 mg/ml, less than limited value (100 mg/ml) by WHO. Abnormal toxicity test showed no abnormal signs when 0.2 ml of the antivenom injected intraperitoneally in mice. •First record of LD50 of H. Saulcyi via s.c. route.•First study for preparation of F(ab’)2 in domesticated horses in Iraq.•The efficacy potential of scorpion antivenom effect and immunization of the horses.•High purity of F(ab’)2 antivenom prepared by ammonium sulfate precipitation.