Production of Anti-Sheep Hemolysin in a Donkey

Abstract

In the complement fixation test for the diagnosis of syphilis or other diseases, it is usual to use an anti-sheep hemolysin for the production of whiclv rabbits have been employed almost exclusively. Numerous methods have been proposed for the immunization of these animals to produce a high titer serum, but we have found in our routine immunization of such animals that they vary considerably in their individual response to the injections of sheep erythrocytes.

For a routine diagnostic laboratory handling a large number of Wassermann tests where a constant and reliable supply of hemolysin is required, it seems desirable to immunize a larger animal which will yield a supply of hemolysin sufficient to last for a number of years. This will obviate the necessity of immunizing rabbits for this purpose at short intervals and will result in an economy in time and money. Attempts have been made to produce anti-sheep hemolysin on horses but Gilbert 1 was unable to produce it in a horse showing no natural hemolysin in the blood, but was successful with a mule having a small amount of hemolysin before immunization. As these animals are rather costly, it appears to us worth while to find a less expensive experimental animal.

Our choice has accordingly fallen on the donkey, a common beast of burden, which is relatively inexpensive, costing about 20 times the price of a rabbit here, and is of a convenient size for our purpose. Before immunization the blood of the donkey was first tested for the presence of natural anti-sheep hemolysin, but not a trace of it was present. Immunization was then begun by a series of inoculations given through the ear vein. All series of injections were given on 3 successive days at 4-day interval between each series and trial bleedings were taken each day before injection.