Biomedical subjects

C von Allmen

Publications and source records attributed to C von Allmen.

23 records · Page 2Linked to original sources

PubMed1990

Platelet-activating factor- and leukotriene B4-induced release of lactoferrin from blood neutrophils of atopic and nonatopic individuals.

We found increased accumulation of neutrophils and their components, lactoferrin (Lf) and elastase, as well as platelet-activating factor (PAF) and leukotriene B4 (LTB4) at sites of ongoing human allergic reactions. To determine whether PAF or LTB4, could be the stimulus for in vivo Lf release, blood neutrophils of 17 subjects were incubated with PAF, LTB4, or the phorbol ester, phorbol myristate acetate (PMA), and the released Lf (ELISA assay) was compared with spontaneous release. Significantly increased Lf release was induced by PAF, 10(-5) to 10(-8) mol/L (p less than 0.002); LTB4, 10(-7) to 10(-8) mol/L (p less than 0.004); and PMA (0.05 micrograms/ml) in a dose-dependent reaction. Cytochalasin was not required for Lf secretion but did enhance such responses. PAF-induced Lf secretion was inhibited by the specific PAF antagonist, BN 52063. More Lf was released from neutrophils of atopic than from nonatopic subjects in response to PAF, 10(-6) mol/L (4.2 micrograms/ml +/- 0.2 versus 2.6 micrograms/ml +/- 0.2; p less than 0.001) but not to LTB4, PMA, or buffer (p, not significant). We conclude that (1) PAF and LTB4 released in vivo could stimulate local neutrophils to release Lf with possible pathogenic effects and (2) neutrophils of atopic subjects are more responsive to PAF than neutrophils of nonatopic subjects in this regard.

Adult↗

PubMed1987

Increased expression of CR3 (C3bi receptor) on neutrophils in human inflammatory skin reactions.

To help determine whether the neutrophils (PMN) found in skin inflammatory reactions are activated, we have compared the expression of the C3bi receptor (CR3) on such cells with that on autologous blood PMN in 10 pollen-sensitive subjects. Using skin chambers overlying denuded blister bases we collected PMN at 2 or 4 hr at sites of challenge with pollen antigen or buffer solution. These cells and PMN in autologous blood were incubated with monoclonal anti-CR3 antibody and the expression of CR3 was measured by indirect fluorescence and flow cytometry. Significantly more PMN were found at antigen than at buffer sites at 2 hr (7.02 +/- 0.45 X 10(5) vs 0.71 +/- 0.25 X 10(5] and at 4 hr (2.2 +/- 0.57 X 10(6) vs 5.47 X 10(5). The mean CR3 expressions on PMN at antigen and buffer sites were similar (117 +/- 7.4 vs 118 +/- 9.0); both were significantly greater than on blood PMN (17.6 +/- 1.5; P less than 0.005). PMN from both sites could be stimulated further in vitro with formyl-methionyl-leucyl-phenylalanine (FMLP) to express more CR3 to a level even greater than in FMLP-stimulated blood PMN (155 +/- 11 and 157 +/- 12, respectively, vs 108 +/- 7 in blood PMN). The incubation of blood PMN with the noncellular component of the chamber fluid led to a moderate (28-100%) increase in CR3 expression, but far less than the CR3 expression on the chamber fluid PMN themselves. Since surface CR3 is thought to be an activation marker important in PMN adhesion, these findings may be important in understanding the emigration of PMN in skin inflammatory reactions.

Adult↗

PubMed1987

Cellular inflammatory responses in human allergic skin reactions.

To define better the role of inflammation in the response to pollen antigens, we have used our skin chamber model to study inflammatory cells recovered from the sites of ongoing allergic reactions. In 15 atopic subjects, paired skin blister sites were simultaneously challenged with ragweed- or grass-pollen antigen or buffer for 5 hours. There were 10 times as many cells recovered at antigen (20.7 X 10(5)) than at buffer (2.0 X 10(5)) sites, p less than 0.005; greater than 97% of the cells recovered were neutrophils. The number of cells recovered at the antigen sites correlated with the total amount of histamine released (r = 0.57; p less than 0.05) but not with the extinction dilution skin test reactivity nor with the intensity of the late cutaneous allergic response measured 6 hours after the injection of antigen. Phase-contrast microscopic examination of the cells recovered from the antigen sites demonstrated that 82% to 95% were polarized compared to 0% to 1.5% of autologous blood neutrophils obtained simultaneously from the peripheral blood. Antigen site cells were as capable of serum-dependent phagocytosis as peripheral blood neutrophils. There was no significant difference in the migratory response to buffer, the chemoattractant N-formyl-methionyl-leucyl-phenylalanine, or leukotriene B4, but there was a significantly decreased response to platelet-activating factor when the cells recovered from antigen sites were compared to autologous blood neutrophils.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens↗

PubMed1987

Neutrophil activation in human inflammatory skin reactions.

To determine the functional activity of neutrophils emigrating to the sites of ongoing human allergic inflammatory reactions, we assessed the intensity of their intracellular oxidative metabolism by measuring the intracellular oxidation by H2O2 of the dye, 2',7'-dichlorofluorescein diacetate (DCFH-DA), to fluorescent 2',7'-dichlorofluorescein. The intensity of intracellular fluorescence was measured by flow cytometry. In 13 atopic subjects, two denuded skin blister bases were challenged for 5 hours with pollen antigen and two blister bases with buffer. Both the level of histamine and mean number of cells recovered at antigen sites were greater than at buffer sites. Oxidation of DCFH-DA by neutrophils recovered from both antigen and buffer sites was significantly greater than that of autologous peripheral blood neutrophils (PBNs), reflecting an increase in the spontaneous generation H2O2 of cells recovered from the sites of inflammation. DCFH-DA oxidation by cells recovered from sites of antigen incubation was significantly greater than cells from buffer site incubations. Neutrophils from both antigen and buffer sites could be stimulated further in vitro by phorbol myristate acetate to the same level of H2O2 generation as phorbol myristate acetate-stimulated PBNs. In five subjects studied, the noncellular component of chamber fluids collected at 1 and 5 hours stimulated PBNs to increase their oxidative metabolism by 42% to 62%; however, this increased level of intracellular H2O2 was still much less than the spontaneous H2O2 generation observed in cells recovered from sites of allergic inflammation. The increased oxidative metabolism of neutrophils in human allergic and inflammatory skin reactions has important pathophysiologic implications for the role of these cells in inflammatory responses.

Adult↗

PubMed1978

Specific cell-induced transformation of Paramecium surface antigens.

Paramecia may induce in other paramecia specific changes in the expression of genes determining surface protein synthesis, probably via cell-to-cell contact. Transformation from one antigenic type to a newly induced one is stimulated by the pretreatment of a cell with 5-fluorouracil. These observations are considered in terms of the regulation of the activity of genes in stable cells and in unstable cells which tend to transform spontaneously.

Animals↗