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Insect cell stimulation by LPS requires the activity of cell‐released proteases
Author(s) -
Wittwer Daniela,
Wiesner Andreas
Publication year - 2001
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.14
Subject(s) - proteases , proteolysis , lipopolysaccharide , lysozyme , biology , macroglobulin , stimulation , microbiology and biotechnology , biochemistry , immune system , cell culture , cell , protease , enzyme , immunology , endocrinology , genetics
The hemocyte line BTI‐EA‐1174‐A from the lepidopteran insect Estigmene acraea responds to bacterial lipopolysaccharide (LPS) by an enhanced phagocytic reaction and a dose‐dependent increase of lysozyme release [Wittwer et al., Dev Comp Immunol 21 :323 (1997)]. This paper provides evidence for a strong proteolytic activity in cell culture supernatants occuring after addition of LPS (1 mg/ml). The proteolysis is caused by cell‐released proteases and seems to be necessary for cell activation. Its inhibition by α 2 ‐macroglobulin results in a dose‐dependent reduction in cellular response strength. Phagocytic reactions, as well as lysozyme release, are lowered to about half in the presence of 0.0001 mg/ml α 2 ‐macroglobulin. A nearly complete abolishment of activation was achieved with final concentrations of 1.0 mg/ml α 2 ‐macroglobulin. The data presented allow us to conclude that the LPS‐triggered proteolytic activity is an important part of the activation process; it occurs outside of the cells and delivers immune response activating factors. Arch. Insect Biochem. Physiol. 39:91–97, 1998. © 1998 Wiley‐Liss, Inc.