Inhibition of Cysteine Proteinase from Schistosoma mansoni Larvae by α-Macroglobulin from the Plasma of Biomphalaria glabrata

• Published in: The Journal of parasitology 1996-04, Vol.82 (2), p.343-347
• Main Authors: Fryer, Sarah E., Bender, Randall C., Bayne, Christopher J.
• Format: Article
• Language: English
• Subjects: alpha-Macroglobulins - isolation & purification; alpha-Macroglobulins - pharmacology; Animals; Biochemistry. Physiology. Immunology; Biological and medical sciences; Biomphalaria - metabolism; Biomphalaria - parasitology; Biomphalaria glabrata; Blood plasma; Cysteine Endopeptidases - isolation & purification; Cysteine Endopeptidases - metabolism; Cysteine Proteinase Inhibitors - blood; Cysteine Proteinase Inhibitors - isolation & purification; Cysteine Proteinase Inhibitors - pharmacology; Freshwater; Fundamental and applied biological sciences. Psychology; Hemocytes; Hemolymph; Hemolymph - chemistry; Host parasite relationships; Host-Parasite Interactions; Invertebrates; Larva - drug effects; Larva - enzymology; Larvae; Mollusca; Mortality; Parasite hosts; Parasites; Parasitology; Physiology. Development; Research Notes; Schistosoma mansoni; Schistosoma mansoni - drug effects; Schistosoma mansoni - enzymology; Schistosoma mansoni - physiology; Sodium
• ISSN: 0022-3395; 1937-2345
• DOI: 10.2307/3284177

The hemolymph of Biomphalaria glabrata, a molluscan host of Schistosoma mansoni, contains an a-macrogobulin proteinase inhibitor (αM). In this study we have demonstrated that this host molecule inhibits a cysteine proteinase produced by larval S. mansoni. Inhibition by αM involves conformational changes through proteolytic cleavage by the proteinase, thus the enzyme must be active for interactions to occur. A specific cysteine proteinase inhibitor (E64) was used to block the interaction between parasite cysteine proteinase and host αM during an in vitro parasite killing assay. Increased sporocyst mortality was not observed in hemolymph from susceptible strains of B. glabrata when E64 was included, nor was there decreased killing in similarly treated hemolymph from a resistant strain. This suggests that the inhibition of this parasite proteinase by host αM is not involved in processes determining either resistance or susceptibility to this trematode.