Interaction of plasma fibronectin (pFN) with membranous constituents of peritoneal exudate cells and pulmonary macrophages
The prominent role of plasma fibronectin (pFN) in the host defense system as an opsonin for gelatin (collagen)-coated colloids has been established. In the present study the authors investigated the interaction of pFN and membrane isolates from cells devoid of collagen, as well as several tissues. In a liver slice assay system it was shown that subcellular membrane fractions from lung macrophages, peritoneal exudate cells, spleen, testis, and liver were able to competitively inhibit the pFN-mediated uptake of /sup 125/I-gelatin coated latex beads (gLtx) at low concentrations. Endocytosis of /sup 125/I-labeled membrane isolates by macrophage monolayers was also promoted by addition of pFN. In an attempt to characterize the membrane component(s) interacting with pFN, it was found that mild extraction procedure with 1 M KBr could release a significant amount of this inhibitory activity. Further studies demonstrated that the agent(s) responsible for inhibition of gLtx uptake was heat sensitive, not altered by trypsin treatment, and did not contain actin, a protein known to interact with pFN. This work indicates that pFN interacts specifically with an as yet unknown membrane component(s) and that such interaction will promote clearance of cellular debris by macrophages. This suggests that pFN may be an important opsonin for the reticuloendothelial system in clearance of collagenous and noncollagenous cellular debris once they are exposed to interact with it.
- Research Organization:
- Univ. of Illinois, Chicago
- OSTI ID:
- 5779448
- Journal Information:
- J. Leukocyte Biol.; (United States), Journal Name: J. Leukocyte Biol.; (United States) Vol. 36:5
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ANIMAL TISSUES
ANTIBODIES
BETA DECAY RADIOISOTOPES
BIOCHEMISTRY
BODY
CELL CONSTITUENTS
CELL MEMBRANES
CHEMISTRY
CONNECTIVE TISSUE CELLS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
IMMUNITY
INHIBITION
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
LUNGS
MACROPHAGES
MEMBRANES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PERITONEUM
PHAGOCYTES
PHAGOCYTOSIS
PROTEINS
RADIOISOTOPES
RESPIRATORY SYSTEM
RETICULOENDOTHELIAL SYSTEM
SEROUS MEMBRANES
SOMATIC CELLS
TISSUES
UPTAKE