Fibronectin associated with infiltrating T lymphocytes. Evidence for in situ localization in biopsies and synthesis in vitro

Abstract

Dermal and mucosal lymphocyte infiltrates in patients with lichen ruber planus and chronic graft-vs.-host disease exhibited reactivity with anti-fibronectin antibodies. This reactivity was associated with the lymphocytes and localized pericellularly. In contrast, biopsy areas outside lymphocyte accumulations were relatively devoid of reactivity with anti-fibronectin antibodies. Furthermore, the corresponding biopsies from healthy individuals or patients without lymphocyte infiltration showed negligible reactivity with anti-fibronectin antibodies. The fibronectin associated with infiltrating lymphocytes in biopsies may be exogenous of non-lymphoid origin. However, another possibility suggested by in vitro experiments is that this fibronectin is lymphocyte derived. Thus, during cultivation in vitro lymphocytes appear to synthesize a component with fibronectin-like properties. Furthermore, a prerequisite for detection of this synthesis was that the cells were cultured in the presence of serum depleted of fibronectin. These results point to the possibility that fibronectin may play a role for lymphocyte interactions with tissues during infiltrative processes.

Expression of Extracellular Matrix Ligands and Receptors in the Muscular Tissue and Draining Lymph Nodes of mdx Dystrophic Mice

“…Furthermore, fibronectin and laminin induce in vitro production of TNF-␣ and IL-1␤ by macrophages and lymphocytes via integrin receptors (21). In this regard, knowing that in chronic inflammatory diseases T lymphocytes are often associated with ECM components (10,22), the increased expression of ECM components in both lymphoid tissues and lesioned skeletal muscle would contribute to local regulation of proliferation and cytokine production by infiltrating T lymphocytes. Thus, altered ECM production in the dystrophic skeletal muscle (13) in association with locally secreted cytokines and/or released antigens from the foci of myonecrosis may be functioning as an attractant for leukocyte immigration and perpetuation of the process.…”

Fibronectin at the Lymphocyte Surface. Evidence for Activation‐Dependent Binding to VLA4 and VLA5 Integrins

“…Gelatin-bound material was eluted using 8 M Urea and subsequently dialysed and lyophilized. The gelatin-binding iodinaied components were then separated on a 6"/;, SDS PAGB gel and transblotted and reacted with anti-FN antibodies as described earlier [16]. Human plasma FN (Sigma) was labelled with ['H]-NaBH4 (Amersham, Bucks, UK) using Ibe reductive methylation method as described elsewhere [19].…”

“…We have previously presented evidence that FN is asso-ciated with infiltrating lymphocytes in biopsies [16]. This raised a number ofquestions on whether FN can be bound to the lymphocyte surface and concerning the origin of such putative lymphocyte surface fibronectin.…”

Short‐term phytohaemagglutinin‐activated mononuclear cells induce endothelial progenitor cells from cord blood CD34+ cells

“…These data suggest that fibronectin is an integral part of both EC ontogeny and vessel formation. Activated lymphocytes are known to produce fibronectin (Sundqvist et al , 1991; Hauzenberger et al , 1996). Therefore, it is very probable that fibronectin produced by activated lymphocytes plays an important role in lymphocyte‐supported EC induction.…”

“…In these systems, Flk-1 2 ESs differentiate to Flk-1 1 cells, or Flk-1 1 VE-cadherin 2 CD31 2 cells and then into Flk-1 1 VE-cadherin 1 CD31 1 cells when appropriately conditioned (Nishikawa et al, 1998). ESs further differentiate to the putative haemangioblasts and finally to ECs with serial phenotypic changes in Flk-1, CD31 and VE-cadherin (Vittet et al, 1996). Embryonic stem cells have been so named as they have been shown to give rise to both haematopoietic and EC lineages and have a Flk-1 1 CD31 1 VE-cadherin 1 CD45 2 phenotype (Nishikawa et al, 1998).…”