The Collagenaselike Enzymes of Skin-Penetrating Helminths

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  • University of Chicago, Department of Microbiology

Our presentation might more accurately be titled a brief summary of studies on the mechanisms involved in penetration of tissues by helminths, rather than the collagenaselike enzymes of skin penetrating helminths. The latter is a significant portion of the broader study, and the title serves to limit this discussion. Throughout the course of our investigations we have utilized a variety of tissue-penetrating helminths (Lewert and Lee, 1954; 1955), but for the sake of brevity we will present material primarily on the activities and characteristics of schistosome cercariae, with some comparisons of these activities with those of the infective larvae of Strongyloides. To date, our investigations have developed through five relatively distinct but interdependent phases which include: histochemical studies of the extracellular changes caused by penetrating larvae; the effect of the physiological state of the host on the extent or degree of these changes; qualitative studies of the nature of the enzymes causing these changes, presumably related to the penetration mechanism; quantitative studies of the collagenaselike enzymes; and finally, studies on the antienzymatic activity of serum from individuals infected with Schistosoma mansoni.