Leukocyte migration agarose test for the assessment of human neutrophil chemotaxis. II. Variables in the attraction assay

Cortactin activation by FVIIa/tissue factor and PAR2 promotes endothelial cell migration

Cellular migration is a complex process that requires the polymerization of actin filaments to drive cellular extension. Smooth muscle and cancer cell migration has been shown to be affected by coagulation factors, notably the factor VII (FVIIa) and tissue factor (TF) complex. The present studies delineated mediators involved with the process of FVIIa/TF-induced cell migration and utilized a simple, precise, and reproducible, migration assay. Both FVIIa and protease-activated receptor-2 (PAR2)-activating peptide, SLIGRL, increased the migration rate of porcine cerebral microvascular endothelial cells (pCMVECs) overexpressing human TF. Ras homolog gene family member A (RhoA) and cortactin were upregulated during the process; expression of HIF, actin polymerization nuclear diaphanous-related formin-1 and -2 (Dia1, and Dia2) were unaffected. Gene silencing by shRNA to PAR2, RhoA, and cortactin attenuated this gene upregulation and migration induced by FVIIa/TF. Utilizing immunocellular localization, we demonstrate that during FVIIa/TF and PAR2 activation, cortactin molecules translocate from the cytoplasm to the cell periphery and assist in lamellipodia formation of pCMVECs. Overall, we demonstrate a novel regulation and role for cortactin in FVIIa/TF-mediated endothelial cell migration that occurs through a PAR2 and RhoA dependent mechanism.

Neutrophils recruited to the lungs of humans by segmental antigen challenge display a reduced chemotactic response to leukotriene B4

Allergic asthma is characterized by an infiltration of the lung with inflammatory cells including eosinophils and neutrophils. The mechanism by which inflammatory cells are recruited to the lung in IgE-mediated disorders is unknown. In order to explore the mechanism responsible for cell recruitment, ragweed-allergic volunteers underwent segmental (bronchoscopic) antigen challenge, followed 24 h later by bronchoalveolar lavage (BAL). Experimental conditions were chosen to favor neutrophil, rather than eosinophil, recruitment. Chemotactic responses of purified BAL neutrophils (under agarose) were then compared with blood neutrophils obtained from the same subjects. We hypothesized that neutrophils recruited to the lung would be desensitized to the chemotaxin(s) responsible for their recruitment. BAL neutrophils showed a profound inhibition of their chemotactic response to an optimal concentration of leukotriene B4 (LTB4) ex vivo (approximately 40% of the response of blood neutrophils) with a slightly reduced response to the anaphylatoxin C5a and to FMLP. In addition, they displayed a normal production of superoxide anion in response to phorbol myristate acetate. These results demonstrate that neutrophils recruited to the lung of humans by local antigen challenge display a marked inhibition of their chemotactic response to LTB4, and are consistent with the hypothesis that LTB4 is instrumental in recruiting neutrophils to the lung in IgE-mediated reactions.

Defective in vitro motility of polymorphonuclear leukocytes of homozygote and heterozygote Chediak-Higashi cats

The in vitro migratory responses of neutrophils of homozygote and heterozygote Chediak-Higashi cats were defective in an under-agarose assay when compared to the behavior of phagocytes of control cats. The linear distances traversed by the leading front of migrating Chediak-Higashi neutrophils toward streptococcal culture supernatant, zymosan-activated serum or buffer were reduced and smaller numbers of Chediak-Higashi phagocytes populated the resulting migration areas than did cells of control animals. The relative migration parameters of the Chediak-Higashi phagocytes, however, did not differ from the corresponding parameters of control neutrophils in the presence of streptococcal culture supernatant. Therefore, phagocytes of homozygote and heterozygote Chediak-Higashi cats recognized and responded equally well to the bacterial stimuli as did cells of control animals but traveled shorter distances primarily because of a reduced inherent motility. Similar results were also obtained when the feline phagocytes were attracted by zymosan-activated serum. In addition the relative migration parameters of the neutrophils of homozygote Chediak-Higashi cats were reduced and the normalized spatial distributions of their migrating cells were significantly different in the presence of 100% and 20% zymosan-activated serum when compared to the corresponding migration parameters of carrier and control animals. Defective recognition or responses to the higher concentrations of these host-derived attractants complicated, therefore, the already reduced inherent motility of the phagocytes of homozygote Chediak-Higashi cats.

Chemotaxis and chemiluminescence responses of synovial fluid polymorphonuclear leucocytes during acute reactive arthritis

The chemotaxis and chemiluminescence responses of polymorphonuclear leucocytes (PMN) of synovial fluid and peripheral blood from patients with acute reactive arthritis were studied. Rates of chemotactic and chemokinetic migration of synovial fluid PMN were significantly decreased. In addition, chemiluminescence responses tended to be depressed, suggesting that the cells were deactivated for both chemotaxis and production of oxygen derived free radicals. Such deactivation has been described previously as a characteristic of synovial fluid PMN in rheumatoid arthritis. Compared with those with a mild disease, patients with severe acute reactive arthritis had higher chemiluminescence responses of synovial fluid PMN to phorbol myristate acetate during acute disease and developed increased migration of peripheral blood PMN towards zymosan treated serum after recovery from the disease. This supports the view that hyperreactive PMN contribute to the development of severe inflammatory symptoms in acute reactive arthritis.

Influence of technical parameters on the in vitro motility of equine neutrophils in the presence of streptococcal culture supernatant

To identify the influence of technical factors on the in vitro motility of equine neutrophils towards streptococcus culture supernatant in an under-agarose assay, we studied the changes in eight cell migration parameters. The distances the phagocytes travelled by directed, random and spontaneous migration increased with incubation time, cell concentration and the gelatin and serum contents of the migration plates. The contribution of chemotaxis to the phagocyte migrations, however, decreased simultaneously. The directed and random, though not the spontaneous, migrations of the phagocytes increased also when the chemoattractant wells were placed closer to the cell wells but so did the influence of the chemokinetic activity of the bacterial culture supernatant on phagocyte motility. In contrast, preincubation of migration plates with the chemoattractant, the agarose content of the migration plates and contamination of the granulocytes with non-migrating, mononuclear cells did not substantially affect the in vitro migrations of the neutrophils. The changes in the in vitro motility of the equine neutrophils by these technical factors were, in general, comparable to those reported for human cells attracted by a variety of host-and bacteria-derived chemoattractants.

Polymorphonuclear leucocyte function and previous yersinia arthritis: enhanced chemokinetic migration and oxygen radical production correlate with the severity of the acute disease

Polymorphonuclear leucocyte (PMN) functions (migration in vitro, chemiluminescence, O-2 production, binding of chemotactic peptide, and aggregation) were studied in HLA-B27 positive patients with previous yersinia arthritis (YA). PMNs of patients whose disease had been severe showed chemokinetic and chemiluminescence responses significantly higher than the PMNs of those with a mild disease. The results support the view that enhanced PMN function contributes to inflammatory symptoms in patients with YA.

Advantages and limitations of methods for measuring cellular chemotaxis and chemokinesis

Cell migration is an important component of many physiological reactions, for example inflammation, wound healing and formation of atherosclerotic lesions. This review summarizes the methods currently available for examining cell movement in vitro. The applications of each method, and its particular advantages and disadvantages are discussed. Techniques are described for preparing purified leukocyte populations for use in migration studies and for differentiating between chemotactic and chemokinetic cell migration.

Chemotaxis under agarose: dependence upon polymorphonuclear leukocyte density

Since the number of polymorphonuclear leukocytes (PMN) responding to a chemotactic stimulus in the Boyden chamber is influenced by the cell density, we studied whether this variable was important in determining chemotaxis under agarose. The chemotactic index was determined by summing the product of each cell that had migrated from the chemotactic well by its distance and correcting this sum for random migration. Cell density (number of PMN per mm2 surface area of the agarose plate well) influenced the number of cells responding to the chemotactic stimulus. Only when more than 1.8 x 10(2) PMN/mm2 were used was chemotaxis then detected. For cell densities greater than this number, there was a highly positive correlation between cell density and chemotactic index (P less than 0.001). These findings are consistent with previous reports and indicate that PMN density is a critical variable when using the agarose method. In addition, these studies provide further evidence for cellular cooperation in the initial phases of the chemotactic response.

Neutrophil chemotaxis under agarose: a statistical analysis and comparison of the chemotactic response of cells from different donors

Distance of migration and cumulative cell count were determined in parallel to quantitate migration of polymorphonuclear leukocytes (PMNs) of healthy volunteers in the chemotaxis-under-agarose assay. The cumulative percent distributions of the rates of spontaneous migration in the absence of an attractant, of chemokinetic migration in zymosan-activated human serum (ZAS) incorporated in agarose, and of chemotactic migration toward ZAS were approximately normal. Cord blood PMNs are known to respond poorly to ZAS in vitro; this was used to determine whether the chemotactic indices (CI: ratio of migration toward ZAS to spontaneous migration) and the chemotactic differentials (CD: difference between migration toward ZAS and spontaneous migration) correlated with impaired chemotaxis under agarose. Both CI and CD values of cord PMNs were significantly low, indicating a positive correlation. The CI values of healthy volunteers correlated negatively with spontaneous migration, whereas the correlation of the CD values was neither negative nor positive. Since spontaneous migration of PMNS varies, the results support the use of CD values when comparing chemotactic responses of PMNs from different donors; e.g., the CD values were determined to evaluate the responsiveness of HLA-B27-positive PMNs, which we recently found to migrate under agarose toward ZAS more than HLA-B27-negative PMNs. The CD values of HLA-B27-positive PMNs were significantly high, indicating that the cells were high responders.

Chemotaxis under agarose utilizing human serum depleted of C-5 derived peptides

An immunoabsorbent column was made with antibody to trypsinized human C5. This column removed the chemotactic activity from zymosan-activated serum as well as from C5a des-arg-enriched fractions. Anti-trypsinized C5-absorbed human serum was substituted for unabsorbed human serum in the chemotaxis under agarose system. This resulted in significantly reduced random neutrophil migration with a negligible effect on C5a des-arg or FMLP-directed migration. The results indicate that much of the random migration observed in the chemotaxis under agarose system is due to C5-derived peptides present in normal human serum.

A modified leukocyte migration under agarose technique (LMAT). Technical aspects

Variables influencing the cell environment were investigated and found to have a profound influence on polymorphonuclear leukocyte migration and chemotaxis, using the LMAT (leukocyte migration under agarose technique) as the test system. Temperature, pH, gas mixtures, time allowed for migration and storage of leukocyte suspensions were all found to be critical factors for the migration response. The presence of divalent cations and protein in the leukocyte suspension were found as well to be essential for cell migration. the influence of different chemo-attractants on cell migration in the LMAT was investigated, and a previously unreported limitation regarding the use of serum was delineated. Serum was found to behave satisfactorily as a chemotactic factor only in freshly-made agar matrices, a consequence most probably due to the development of anti-complementary activity in agar. The technical factors influencing the modified LMAT and problems concerned with the test variables are discussed.

Increased chemotactic activity of neutrophil leukocytes in psoriasis

The random and active migration of neutrophil leukocytes in agarose was studied in sixty-one patients with psoriasis and in healthy controls. E. coli filtrate was used as chemoattractant. The random as well as the active migration was increased in psoriasis. The increase was most pronounced in those cases with widespread psoriasis. In twenty patients who were followed for 1-3 years, the neutrophil chemotactic activity remained essentially unchanged.

Quantitation of chemotactic factor generation in human sera

Increased sensitivity of chemotaxin titration in the 'migration under agarose' method was achieved by reduction in agarose concentration of the medium from the conventional 1.0% to 0.5%. Satisfactory technical properties of the gel were achieved by inclusion of 2.0% bovine serum albumin. The modificatin resulted in increased migration rates and greater reproducibility than those achieved with other media. The range of normal values was established by study of sera of 20 normal adults with use of a single batch of target cells. It is concluded that under the conditions described, a difference in chemotactic differential of 10% or more between a serum sample submitted for assay and that of pooled serum from normal subjects is statistically significant.

Chemotaxis in yersinia arthritis. HLA-B27 positive neutrophils show high stimulated motility in vitro

Chemotaxis, chemokinesis, and spontaneous locomotion of polymorphonuclear leukocytes (PMNs) of yersinia arthritis (YA) patients and healthy subjects with or without HLA-B27 were studied by agarose assay and membrane filter technique. HLA-B27 positive healthy control subjects and yersinia patients showed significantly higher response to chemotactic stimulus than HLA-B27 negative controls. Consequently, the high response was associated with HLA-B27 irrespective of YA. The high responder PMNs may contribute to the more severe inflammatory symptoms in YA patients with HLA-B27.

Neutrophil chemotaxis defect in IgA deficiency evaluated by migration agarose method

The chemotactic and random mobility functions of twelve selectively IgA-deficient patients were evaluated by a method using agarose gel. A severe polymorphonuclear cellular chemotactic defect was found in ten out of twelve patients, but only five of them also showed a marked associated impairment of random locomotory function. Furthermore, in one subject, levamisole therapy resulted in a dramatic improvement of both chemotactic and random mobility functions. These results are discussed in the paper with respect to the possible pathogenetic implications.

The chemoattractant properties of comedonal components

Acculation of clusters of polymorphonuclear leukocytes (PMN) along the periphery of the walls of comedones (predominantly of the closed variety), has been described as the first change marking the transition of quiescent, noninflamed lesions in acne, into inflammatory ones. The present study analyzed the chemoattractant properties of different comedonal components for human PMN in an effort to evaluate the potential significance of these substances in stimulating the chemotactic response of PMN in the initial phases of inflammatory acne. It was found that the lipids extracted from pooled comedones had chemotactic activity for PMN in vitro. Beyond that, all chemotactic activity in comedones was related to bacteria. Propionibacterium acnes produced low molecular weight, dialyzable, heat stable chemotactic factors which were released into culture medium during bacterial growth. In addition to the extracellular cytotaxins, P. acnes whole cells and other extracellular products were strong cytotaxigens and activated heat labile chemotactic factors in human and guinea pig serum.

Leukocyte migration agarose test for the assessment of human neutrophil chemotaxis. I. Effects of environmental factors on neutrophil migration under agarose

To apply the leukocyte migration agarose test (LMAT) to the in vitro assessment of human neutrophil chemotaxis, effects of different culture conditions on neutrophil migration under agarose were studied. Presence of either serum or human serum albumin (HSA) in the culture medium was necessary for detectable neutrophil migration. HSA was preferred since heat-stabile chemotactic agents were found to be generated from fresh serum in the presence of agarose. Additional CO2 in the assay milieu could be replaced by decreasing the NaHCO3 concentration of the culture medium. Both the directed and the spontaneous migration rates of neutrophil leukocytes increased when the concentration of agarose was decreased. Area and distance of migration and cumulative cell count of migrated neutrophil leukocytes were suitable for quantitating the neutrophil migration rate.