Summaryalso show defective chemotaxis, thereby suggesting an association --between capping and movement in PMNS.-P~Y~~~P~~~~~~~~~ leukocytes (PMNs) have previPMNs from normal human neonates also show deficient themously been shown be chemotactically deficient' To probe the otaxis (2,4,8). To better characterize the nature of this defect, we mechanism(s) responsible for this deficiency, we have investigated studied capping in neonatal PMNs, both spontaneously and in the phenomenon of concanavalin A-induced capping in neonatal response to with colchicine. PMNs. PMNs horn cord blood of 17 healthy, full-term infants and 17 normal adult volunteers were isolated by standard Ficoll-Hypaque and dextran sedimentation. After incubation with and without colchicine, the cells were reincubated with fluorescein isothiocyanate-Con A, fixed, and prepared in wet mounts. Using a fluorescence microscope, PMNs were identified, and the percentage of the capped cells was counted.Upon treatment with colchicine, adult PMNs showed a significant increase in the percentage of capped cells. By contrast, the cord blood PMNs showed no significant increase in capping after colchicine treatment. The difference between percentage of PMNs showing colchicine-induced capping in adult and cord blood was highly significant ( P < 0.01; Student's t test). SpeculationIncreasing evidence suggests that a primary developmental deficiency of neonatal polymorphonuclear leukocyte movement plays an important role in the compromised inflammatory response characteristic of this period of life. The data presented in this report strengthen the argument that the level a t which the developmental deficiency operates is at the cell membrane. Future studies should be directed towards determining whether this represents a primary membrane abnormality or, rather, reflects a defect of cytoskeletal or other submembranous components. Such knowledge-would hopefully lead to improved therapeutic enhancement of the efficiency of neonatal polymorphonuclear leukocyte movement.Chemotaxis of human polymorphonuclear leukocytes (PMNs) involves interactions between the cell membrane and several cytoplasmic cytoskeletal elements-the microtubules and microfilaments. The precise nature of these relationships, however, is unclear. Among the available in vitro probes for characterizing these interactions is "capping," or the accumulation of ligandreceptor complexes at a localized site (9).In lymphocytes, capping can be induced by incubation with polyvalent ligands such as antibodies.Capping in normal human PMNs can abo be demonstrated after exposure to the lectin, concanavalin A (Con A). In normal PMNs, however, Con A capping is significantly increased by incubation of cells with an agent such as colchine, a microtubule disrupter (6).By contrast, PMNs from patients with Chediak-Higashi syndrome do not require preincubation with colchicine and will significantly cap just upon Con A treatment (6, 7). Such PMNs MATERIALS AND METHODSCord blood from normal human term neonates was obtained imm...

The orientation (chemotaxis) and locomotion (chemokinesis) of human polymorphonuclear leukocytes (PMNs) are generated by an internal movement mechanism that involves active cytoplasmic movement; they are influenced by external environmental and ionic conditions. We have studied the degree to which the orientation and movement mechanisms of PMNs are self-contained within the cell and the degree to which they are under membrane control. PMNs were partially and selectively demembranated by treatment with the non-ionic detergent, octyl-phenoxyl-polyethoxyethanol (commercially known as Triton X-100) under controlled conditions. The tritonated PMNs (referred to in the literature as models) were non-motile and non-locomotory. Addition of ATP/Mg++ with a trace amount of Ca++ to the medium was followed by reactivation of the tritonated PMN models to move again as motile cells. Although these reactivated PMN models actively locomoted, they could no longer orient to chemoattractants. Thus, the reactivation process restored the physical self-contained movement parameters but could not reestablish the orientation capacity (chemotactic responsiveness) that was characteristic of live PMNs. The demembranation process apparently destroyed the chemotactic receptors and/or eradicated the coordination function of the membrane. Videotapes of normal (control) as well as reactivated PMN movement were analyzed for movement characteristics. These characteristics were objectively analyzed with a newly designed computer-assisted micro-image-processing technique whereby the videotapes were digitized and quantified and the actual PMN movement printed out in computer-graphics and tracings (Freeman codes) for confirmation of orientation and movement arising as a result of reactivation.

The technique of capping, a probe designed to evaluate the fluidity and functional competence of human polymorphonuclear leukocytes (PMNs), has been successfully adapted for rhesus monkey PMNs. The capping characteristics of rhesus monkey PMNs are very similar to those of human PMNs. Utilizing this capping technique as an evaluation tool and with fetal/neonatal rhesus monkey as a functional animal model, the ontogeny of movement and chemotactic characteristics of PMNs can TOW be studied.