Studies of the Sparing Effect of Lymphocytic Choriomeningitis on Experimental Poliomyelitis

Abstract

The criteria used in establishing the sparing effect of lymphocytic choriomeningitis on experimental poliomyelitis have been the clinical behavior of the animals and survival (1–2). Since the diseases are dissimilar in the monkey and poliomyelitis of the kind we have used is almost invariably fatal, these criteria have sufficed not only to determine that an effect occurs, but also to establish certain features of this effect. To extend our knowledge, other criteria seemed necessary. The present report is based on determinations of the infectivity of appropriate tissues of monkeys influenced by both diseases. Methods. Poliomyelitis has been produced, as in the earlier experiments, by the intracerebral injection of 0.2 cc. of the supernate of a 10 per cent centrifuged emulsion of pooled monkey cord. Mixed virus (MV) has been used. In all but the preliminary experiments monkeys were sacrificed when their temperatures fell to 98°F. This was done for several reasons.