Venom and Antivenom of the Redback Spider (Latrodectus hasseltii) in Japan. Part II. Experimental Production of Equine Antivenom against the Redback Spider.

This is the first report on large-scale experimental production of an equine antivenom against the redback spider (Latrodectus hasseltii) lived in Japan. We captured 10,000 redback spiders in Japan and prepared the toxoids of crude venom extract, mixed the toxoids with a mineral oil adjuvant, and immunized healthy horses repeatedly over a period of several weeks. Thereafter, we separated the horse plasma, purified the γ-globulin fraction, and stocked it as a purified antivenom concentrate. Consequently, we manufactured approximately 6,500 vials of a single-dose freeze-dried test lot from a portion of the purified γ-globulin fraction, equivalent to the extract derived from 520 spiders. This test lot had an antitoxin titer comparable to that of a similar drug commercially available overseas (a liquid preparation), and the other quality met all quality reference specifications based on the Minimum Requirements for Biological Products and other guidelines relevant to existing antivenom drug products in Japan.

Attempt to curtail the observation period of mice in the tetanus vaccine potency tests.

Curtailing the observation of mice challenged with tetanus toxin in potency test of tetanus vaccine would reduce the agony of mice from spastic paralysis. From the viewpoint of animal welfare, we investigated the feasibility this measure. The potencies of 85 lots of vaccine obtained on the 4th day after challenge were compared with those obtained on the seventh day. No significant difference was found (P = 0.05), indicating that the observation period could be curtailed from 7 days to 4 days without impairing the assessment of the vaccine's potency.