TRICHINELLA-SPIRALIS - SYNTHESIS OF TYPE-IV AND TYPE-VI COLLAGEN DURING NURSE CELL-FORMATION

The portion of skeletal muscle fiber (Nurse cell) harboring Trichinell a spiralis is surrounded by an acellular capsule susceptible to digest ion with collagenase. Antibodies recognized type IV and type VI collag en in the capsule, while the periodic acid Schiff reagent stained the capsule differentially, revealing at least two distinct layers. RNA an alysis showed that mRNA specific for type IV and type VI collagen was present in muscle tissue on Days 9 and 15, but not on Day 3, following intracellular infection. In situ hybridization showed that most of th e mRNA for both types was within the Nurse cell, and all enlarged Nurs e cell nuclei were transcriptionally active for those messages. Synthe sis of type IV collagen mRNA was absent by Day 24. In contrast, type V I collagen mRNA was still present at 24 days and 8 months. These resul ts support the hypothesis that T. spiralis, either directly or indirec tly, influences the synthesis of these two collagen types throughout i ts own developmental cycle in the Nurse cell. (C) 1997 Academic Press.