Alterations in total serum proteins and protein fractions in Biomphalaria glabrata parasitized by Schistosoma mansoni

Abstract

Samples of serum from healthy Biomphalaria glabrata and from those infected with the larval stages of Schistosoma mansoni were subjected to quantitative electrophoretic analysis and total protein determinations. In the case of the infected snails, samples of serum were taken at 14 time intervals post-exposure to 5 miracidia ranging from 1 hr to 70 days. A total of 34 serum protein fractions have been identified in the hemolymph of uninfacted B. glabrata, although all these fractions usually do not occur in every snail. In infected snails, there is a gradual reduction in the staining intensity of the serum protein fractions until day 35 post-exposure to miracidia, and this is correlated with a reduction in the total serum protein concentration. By day 70 post-exposure to the parasite, the total protein concentration had declined to one-third of that in uninfected snails. Although the decrease in the amount of serum protein fractions as a result of parasitization by S. mansoni is generally nonselective; i.e., almost all the fractions are reduced, three fractions, 7, 9, and 10, do not appear to be reduced in quantity. These remain essentially unaltered in their intensity to staining for up to 70 days, the duration of this experiment. It is postulated that the reduction of serum protein is due to utilization by sporocysts of S. mansoni.