Viral infections are known to exacerbate asthma and other lung diseases where chronic inflammatory processes are implicated, but the mechanism is not well understood. The viral mimetic, polyinosine-polycytidylic acid (poly I:C), causes accumulation of a versican- and hyaluronan-enriched extracellular matrix (ECM) by human lung fibroblasts (HLF) with increased capacity for monocyte adhesion. The 5-fold increase in versican retention in this ECM is due to altered compartmentalization with decreased degradation of cell-layer associated versican rather than an increase in total accumulation in the culture. This is consistent with decreased mRNA levels for all of the versican splice variants. Reduced versican degradation is further supported by low levels of the epitope, DPEAAE, a product of versican digestion by ADAMTS enzymes, in the ECM. The distribution of hyaluronan is similarly altered with a 3.5-fold increase in the cell layer. Pulse-chase studies of radio-labeled hyaluronan show a 50% reduction in the rate of loss from the cell layer over 24 hours. Formation of monocyte-retaining, hyaluronidase sensitive, ECMs can be blocked by the presence of anti-versican antibodies. In comparison, HLF treated with the cytokines, IL-1 plus TNF, synthesize increased amounts of hyaluronan, but do not retain it or versican in the ECM which, in turn, does not retain monocytes. These results highlight an important role for versican in the hyaluronan-dependent binding of monocytes to the ECM of lung fibroblasts stimulated with poly I:C.