The Cultivation of Vaccinia Virus in Deep Columns of Maitland Medium

Abstract

In the in vitro cultivation of vaccine virus there are significant results which point to oxygen tension as an important factor. Maitland and Laing1 failed to obtain growth under anaerobic conditions. Later, Maitland, Laing and Lyth2 contrasted the multiplication which took place in Carrel flasks at a depth of 1 to 2 mm. with the progressive decrease of virus in test tubes in which the depth of medium was approximately 15 mm. In the flasks, the tissue was spread out just beneath the surface of the medium, while in the tubes the tissue particles were massed at the bottom. The failure of growth in deep cultures has led to the assumption that test tubes are unsuitable containers for cultivation of the virus. But although the explanation of diminished oxygen tension, as offered by Maitland and his coworkers1,2 is in all probability correct, it is possible that deficiency of oxygen in their cultures was due not only to the depth of the container but also to the metabolism of the relatively large tissue inoculum. Rivers and Ward3 have shown that vaccine virus fails to grow in mixtures of serum and Tyrode' s solution if large amounts of tissue are used, and that it is capable of increasing in the presence of remarkably minute amounts. It has seemed worth while, therefore, to determine more precisely the reason for failure to obtain growth in deep layers of medium, and in particular to learn whether success might follow the use of small amounts of tissue in deep cultures. In the experiments which are described, containers of different diameters were used with various depths of medium. The effect of increasing and diminishing the oxygen tension, directly, by mechanically controlling the access of air to cultures, was also studied.