Interleukin-8 and neutrophil leucocytes: adhesion, spreading, polarisation, random motility, chemotaxis and deactivation in assays using 'sparse-pore' polycarbonate (nuclepore) membranes in the Boyden chamber

Abstract

Adhesion, spreading, chemotaxis and deactivation of chemotactic responses of separated human peripheral blood neutrophil leucocytes under the influence of interleukin-8 (IL-8) were tested using a previously described Boyden chamber-type method involving 'sparse-pore' polycarbonate (Nuclepore) filtration membrane. The random motilities of neutrophils in similar concentrations of IL-8 were tested using corresponding chambers with polycarbonate membranes of standard pore densities. In addition, polarisation of neutrophils in suspension in various concentrations of IL-8, and the possibility of deactivation of this polarisation response by IL-8 itself or by N-formyl-methionyl-leucyl-phenylalanine (FMLP) were examined. Neutrophils exhibited maximum chemotaxis to IL-8 in a concentration of 100 ng/ml, and to a degree which was similar to the maximum response to FMLP (10(-7) M). This chemotactic response to IL-8 was markedly reduced by pretreatment of the cells with either 100 ng/ml IL-8 (deactivation) or 10(-7) M FMLP (cross-deactivation). On the other hand, the chemotactic response of the neutrophils to FMLP was reduced by pretreatment with FMLP but was not deactivated by pretreatment with IL-8 (i.e. deactivation but not cross-deactivation). Neutrophils in suspension were maximally polarised by 100 ng/ml IL-8, and to lesser degrees by 1, 10 and 1,000 ng/ml IL-8. The detailed morphology of the polar cells was not distinguishable from that induced by 10(-8) M FMLP. Pretreatment of the cells with either IL-8 or FMLP resulted in no reduction of polarisation in response to subsequent exposure to either agent (i.e. neither deactivation nor cross-deactivation).(ABSTRACT TRUNCATED AT 250 WORDS)