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KM Lohr, CA Kurth, DL Xie, JM Seyer and GA Homandberg
Department of Medicine, University of Tennessee, Memphis.
Proteolytic fragments of fibronectin (Fn) can possess properties not
inherent to intact Fn. Previously, only mixtures of low molecular weight Fn
fragments, and the 120-Kd fibroblastic cell-binding segment, but not intact
Fn, were shown to be selectively chemotactic for human monocytes (MOs). In
order to determine if other structural domains of Fn were responsible, we
tested six Fn fragments. The amino-terminal 72- Kd fragment at 1.5 microns
was about 75% as potent as zymosan-activated serum (ZAS). Its
amino-terminal 29-Kd degradation product at 1.0 micron was about one third
as potent as ZAS. Checkerboard analysis confirmed chemotaxis. Complexing
gelatin to 72-Kd fragments reduced MO chemotaxis by 28% to 30%. Reducing
disulfide bonds in 29- and 72-Kd segments had no effect. A synthetic
peptide containing the thrombin cleavage site between the 29- and 50-Kd
segments of the 72-Kd fragment was chemotactic. The 50-, 190/170-, 35-, and
160/150/120-Kd fragments, and intact Fn were not chemotactic for MOs. The
data suggest that the 72-Kd fragment and its 29-Kd subfragment are
additional Fn fragments that mediate selective MO chemotaxis. We speculate
that proteinases present at inflammatory sites can liberate such fragments
that selectively recruit MOs.
This article has been cited by other articles:
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| Copyright © 1990 by American Society of Hematology Online ISSN: 1528-0020 | |||||||||
