Abstract
The role of complement in infections by dermatophytes is unknown. Therefore we evaluated the ability of the dermatophyte Trichophyton rubrum to activate complement in vitro. Aliquots of human plasma that had been incubated with T. rubrum were examined for evidence of complement activation. Following incubation, the total hemolytic complement activity of plasma fell 76%. Further, each T. rubrum incubation led to obvious C3 conversion and generation of polymorphonuclear leukocyte (PMN) aggregating activity. Plasma that had complement activity depleted by heat (56°C x 30 min) or 10 mM EDTA failed to develop C3 conversion or PMN aggregating activity. Complement activation was not affected when the classical complement pathway was selectively blocked by MgEGTA. These studies indicate that T. rubrum can activate the complement system by the alternative pathway. The consequent generation of anaphylatoxins, chemotaxins, and opsonins might be important both in host defense against dermatophytic infections and in the inflammatory reactions mediated by them.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 156-158 |
| Number of pages | 3 |
| Journal | Journal of Investigative Dermatology |
| Volume | 80 |
| Issue number | 3 |
| DOIs | |
| State | Published - 1983 |
Bibliographical note
Funding Information:MATERIALS AND METHODS Isolates of T. rubrum were identified by gross and microscopic examination and growth characteristics on special media. The fungus was grown in nutrient broth medium (DIFCO, Detroit, Michigan) to which 100 11g/ ml of streptomycin and 100 11g/ml of penicillin were added. The broth remaining after harvest 9f the fungus was free of bacteria as determined by culture. Heparinized fresh venous plasma was obtained from random normal donors. Heparin concentration was rigidly controLled (2 units/ml) to avoid inhibition of alternative pathway complement activation [3]. Aliquots of the heparinized plasma were depleted of complement activity by heat (56°C X 30 min) or EDTA (10 mM), or had the classical pathway selectively blocked by the addition of MgEGTA (10 mM) [ 4]. These plasmas were then incubated as described below wilh (a) desiccated T. rubrum., (b) zymosan (as a positive control for complement activation) , (c) a saline blank, or (d) a sample of sterile culture broth. The fo llowing evidence of complement activation was then sought: (a) decrements in total hemolytic comple- Manuscript received May 3, 1982; accepted for publication August 2, 1982. Supported in part by NIH Grants HL 19725, HL 25403, and HL 26218. * Abstracted in Clin Res 29:790A, 1981. Reprint requests to: Dr. Mark V. Dahl, Box 98 Mayo Building, University of Minnesota Medical School, Minneapolis, Minnesota 55455. . Abbreviations: EDTA: ethylenediaminetetraacetate EGTA: ethyleneglycoltetraacetate PMN: polymorphonuclear leukocyte ment (CHr.o), assayed by standard techniques [5], (b) C3 conversion, detected immunoelectrophoretically, and (c) the presence of C5a, assayed as granulocyte aggregating activity [5-7].