CHEMOTACTIC FACTOR RECEPTORS OF HUMAN-PMN LEUKOCYTES .1. EFFECTS ON MIGRATION OF LABELING PLASMA-MEMBRANE DETERMINANTS WITH IMPERMEANT COVALENT REAGENTS AND INHIBITION OF LABELING BY CHEMOTACTIC FACTORS

  • 1 January 1979
    • journal article
    • research article
    • Vol. 37  (2) , 407-418
Abstract
The mechanism of stimulation of human PMN [polymorphonuclear] luekocyte-directed migration by chemotactic factors was studied by pre-labeling plasma membrane determinants with impermeant covalent reagents and assessing the effects of such modification on spontaneous mitration and chemotaxis in modified Boyden chambers. Pre-treatment of PMN leukocytes with 10-9-10-6 M isethionyl acetimidate, which selectively labels amino groups, enhanced spontaneous migration and concomitantly inhibited chemotaxis to fragments to the 5th component of complement (C5fr), 12-L-OH-5,8,10,14-eicosatetraenoic acid (HETE) and several formyl-methionyl (f-Met) peptides to an extent that was inversely related to the magnitude of the chemotactic response of untreated PMN leukocytes. Para-chloromercuribenzene sulfonate, which selectively labels sulfhydryl groups, inhibited chemotaxis to diverse stimuli without substantially influencing spontaneous migration, while the diazonium salt of sulfanilic acid, which labels several types of plasma membrane determinants, altered neither spontaneous nor chemotactic migration. Incubation of PMN leukocytes with various concentrations of [3H]-isethionyl acetimidate labeled from 33,000 amino groups per PMN leukocyte at 10-6 M to over 800,000 at 10-4 M, a reaction that was substantially inhibited by chemotactic concentrations of C5fr and HETE, but not by f-Met peptides. Subcellular fractionation of PMN leukocytes labeled with [3H]-isethionyl acetimidate localized the radioactivity to membrane-rich fractions. Free amino groups are possibly functionally critical determinants of some chemotactic factor receptors on the plasma membrane of PMN leukocytes.