Serologic reactions in Schistosoma mansoni infections. II. Cercarial behavior in electrophoretically separated fractions of sera of infected and uninfected mice

Abstract

Sera from mice with Schistosoma mansoni infections of long duration and control uninfected mice of similar age were separated by moving boundary electrophoresis and photographs were made using the Schlieren scanning method. Samples were withdrawn from the electrophoresis cells at increasing depths from the salt boundaries. Six components were identified in uninfected serum with mobilities similar to albumin, alpha 1, alpha 2, beta 1, beta 2, and gamma globulins. In infected mouse serum, albumin, and alpha globulin areas were reduced and the beta area increased relative to uninfected mouse serum. The alpha 1 and alpha 2 peaks of uninfected mouse serum appeared as a single peak in infected mouse serum. Cercarial behavior was observed in eight globulin samples. The first and second samples below the epsilon boundary were effectively cercaricidal in both uninfected and infected mouse serum. Succeeding samples through the fifth were progressively less so. Beyond the fifth, no cidal activity was observed. Pericercarial envelopes were formed only in the third, fourth, and fifth samples of infected mouse serum. It was concluded from these findings that the first or “gamma” sample of infected mouse serum contained the factors responsible for both cercaricidal activity and pericercarial envelope formation and that the third or “alpha” sample introduced a cercaricidal inhibitor which thus made it possible for the cercariae to form envelopes. Envelopes were found, therefore, only in those infected serum samples which contained both gamma and alpha globulins or serum components with similar mobilities.