A quantitative microassay for leukocyte chemotaxis, using a microscopic slide system with complement-activating yeast particles as gradient source

Neutrophils are hyperactive in recurrent tonsillitis

The pathogenesis of recurrent tonsillitis has not been fully explored. Most studies in this field have focused on pathogenic bacteria whereas less research has been done concerning the host defense. In earlier studies it was shown that there is an active cellular defense in the tonsillar surface secretion, consisting of phagocytes, and therefore in this study the possibility that this defense is altered in patients with recurrent tonsillitis was explored. Neutrophils were obtained from tonsillar surface secretions in eight patients with recurrent tonsillitis and eight healthy volunteers and the capacity of the neutrophils to respond to chemotactic stimuli was examined in an in vitro system. A significantly higher fraction of the neutrophils obtained from the patients with recurrent tonsillitis responded to chemotactic stimuli compared to those obtained from the healthy volunteers. It is concluded that there is a hyperactive cellular defense in the tonsillar surface secretion in patients with recurrent tonsillitis. This finding and its significance in the pathogenesis of recurrent tonsillitis are discussed.

Bacterial clearance and granulocyte response in experimental peritonitis

Clearance kinetics of Escherichia coli and Bacteroides fragilis from the peritoneal cavity and functional properties of peritoneal and blood polymorphonuclear leukocytes (PMNL) were studied in pigs. The bacteria, approximately 10(10) colony forming units (CFU) of each species, were intraperitoneally injected. Blood and peritoneal exudate were sampled regularly during 24 hr for bacterial quantification and PMNL analysis. The peritoneal concentration of both species fell rapidly in the first 3 hr and then stabilized. Approximately 10(2) CFU/ml remained after 24 hr. Chemotaxis, phagocytosis, and metabolic activation of the peritoneal PMNL showed little change. In some pigs a second bacterial dose was injected 6 hr after the first dose and gave an identical clearance pattern. Exhaustion of the local defence capacity thus was excluded as cause of the impaired bacterial elimination.

Influence of fluid-phase chemoattractants on polymorphonuclear leukocyte chemotaxic responsiveness to a surface-bound attractant

Polymorphonuclear leukocytes (PMNLs) were allowed to migrate on slides with fixed yeast particles dotted about on the surface. Locomotion was quantified by counting the number of yeast particles in association with a PMNL. Addition of a complement source to yeast particles able to activate the complement system resulted in a chemotactic response even when fluid-phase attractants were removed prior to the measurement of PMNL chemotaxis, indicating that surface-bound attractants guided the PMNLs to the yeast particles. The presence of high concentrations of fluid-phase chemoattractants resulted in a reduced PMNL chemotactic response to the surface-bound gradient. From comparisons between the yeast-slide system and the locomotion-under-agarose assay, it could be concluded that PMNL chemotaxis in response to a surface-bound gradient is less influenced by factor-specific deactivation than the response to a fluid-phase attractant. The PMNL chemotactic response is reduced to both surface-bound and fluid-phase gradients as a result of a non-factor-specific deactivation.

Concentration gradients in the under-agarose chemotaxis assay system with attractant surface adsorption

To evaluate directional locomotion or chemotaxis of polymorphonuclear leukocytes (PMNL), assay conditions need to be understood quantitatively. The characteristics of the gradient of a chemoattractant in an assay system depend on, for example, the geometry of the system and the diffusion coefficient of the attractant, but since PMNL are able to respond to surface-bound attractants, surface adsorption of the attractant might also be a factor of importance. We have solved the diffusion equation to characterize the gradients present in the under-agarose assay system, when surface adsorption of the chemoattractant is taken into account. Application of the theory to experimental data shows that surface adsorption is important for the cellular response to the chemotactic factor generated from normal human serum, but not for the response to the chemotactic peptide fMLP.

Chemotaxis of polymorphonuclear leukocytes in response to surface-bound complement-derived chemoattractants generated in situ

Polymorphonuclear leukocytes (PMNLs) were allowed to migrate on slides with fixed yeast particles dotted about on the surface. Locomotion was quantified by counting the number of yeast particles in association with a PMNL. Yeast particles that differed in their ability to consume hemolytic complement differed also in their ability to generate chemoattractants. Addition of a complement source to yeast particles able to activate the complement system resulted in a chemotactic response, as well as when fluid-phase attractants were removed prior to the measurement of PMNL chemotaxis, indicating that the chemoattractants generated were absorbed to the surface. Using an immunofluorescence technique, it was found that complement factor 5 coated a circular area around each yeast particle, provided that the particles were able to activate the complement system.