T Cell Fibronectin, Delayed Hypersensitivity and Human Disease

Abstract

Extracellular matrix molecules such as fibronectin (FN) are commonly thought of as structural elements of tissue, and as such, to have limited involvement in the pathogenesis of infectious disease. In point of fact, FN is involved in multiple aspects of the host-parasite relationship. On the host side, a special FN, T cell FN, is produced as a lymphokine by antigen-activated B lymphocytes. T cell FN is associated with initiation of the tissue-damaging delayed hypersensitivity reactions seen in typhoid fever and tuberculosis (Godfrey, 1990). On the parasite side, FN-binding proteins are found in the outer membranes of many bacteria, including Salmonella typhi and Mycobacterium tuberculosis, and may be involved in bacterial adhesion to and/or infection of host cells (Van de Water et al., 1983; Froman et al., 1984; Baloda et al., 1988, 1991; Barnes et al., 1989; George and Falkingham, 1989; Ljungh et al., 1990; Wiker et al, 1990; Visai et al., 1991). Bacterial FN-binding proteins are sometimes major secretory products (Wiker et al., 1986; De Bruyn et al., 1987; Abou-Zeid et al., 1988). For example, FN-binding proteins of the antigen 85 (Ag85) complex are both major mycobacterial secretory proteins and strong immunogens in human beings infected with M. tuberculosis (Kaplan and Chase, 1980; Wiker et al., 1986; De Bruyn et al., 1987; Abou-Zeid et al., 1988; Turneer et al., 1988; Sada et al., 1990). Interactions between FN and bacterial FN-binding proteins can also modulate expression of delayed hypersensitivity in sensitized hosts (Godfrey et al., 1992).