Studies with Chick Embryo Tissue in Cultivation of B. Leprae

Abstract

Since the discovery by Hansen of the acid-fast bacillus in the lesion of human leprosy, many investigators who have attempted its cultivation have considered their “culture” the authentic one. Recently Soule and McKinley 1 in their attempts at cultivation of B. leprae prove no exception to this rule. In an earlier publication², they claim complete success with the CO₂, O₂ method of Wherry 3 regardless of the nutritives employed. McKinley and Verder 4 later claim that they have cultivated B. leprae in 5 days in chick embryo tissue suspended in Tyrode's solution under ordinary atmospheric conditions as well as CO₂ and O₂.

At the suggestion of Dr. Duval I have undertaken to repeat the work of McKinley and Verder. This paper reports results obtained upon that part of the work in which the chick embryo tissue is concerned.

The leprous tissue employed was the subcutaneous nodules and material from the socalled leprous abscess of human lepers, kindly supplied us through the courtesy of Dr. Denney of Carville, La. All the material was extremely rich in acid-fast bacilli as was evidenced upon microscopic examination of stained tissue sections and smear preparations. The Hansen microorganism of leprosy appeared chiefly in densely packed masses (globi) and small packets.

The leprous tissue was first cut into small pieces aseptically, then placed in a mortar and emulsified. A part of the emulsion was treated with a 3% NaOH solution for one hour, and immediately afterward was centrifugally washed several times in sterile Ringer's fluid. Leprous material which was not contaminated was used without treating it with NaOH. In addition, the purported culture of B. leprae in minced chick and Tyrode's solution which was sent to Dr. Duval by Dr. McKinley, was used in parallel experiments. Both liquid and solid media (plain neutral agar) containing the emulsified chick tissue were employed in the experiments.