Tigecycline achieves high intracellular concentrations in polymorphonuclear leukocytes (PMNs). To evaluate the effects of tigecycline on human PMNs, PMNs were incubated with tigecycline dilutions (0.1 to 100 mg L-1). Phagocytosis-associated PMN Fcγ- and complement receptors as well as phagocytosis and oxidative burst induced by Staphylococcus aureus were measured by flow cytometry. Incubation w...

Suppression of host-cell-mediated immunity is a hallmark feature of Yersinia pseudotuberculosis infection. To better understand this process, the interaction of Y. pseudotuberculosis with macrophages and the effect of the virulence plasmid-encoded Yersinia tyrosine phosphatase (YopH) on the oxidative burst was analyzed in a chemiluminescence assay. An oxidative burst was generated upon infectio...

Iron (Fe) is a ubiquitous redox-active element essential for most life. The formation of localized cell wall appositions, the oxidative burst and the production of pathogenesis-related proteins are hallmarks of plant defense responses. Here, we report that iron is a central mediator linking these three phenomena. We show that in response to pathogen attack, reactive Fe3+, but not Fe2+, is depos...

In response to wounding, potato tubers generate reactive oxygen species (ROS) in association with suberization. Immediately following wounding, an initial burst of ROS occurs, reaching a maximum within 30 to 60 min. In addition to this initial oxidative burst, at least three other massive bursts occur at 42, 63 and 100 h post-wounding. These latter bursts are associated with wound healing and a...

Recognition of an avirulent pathogen stimulates an oxidative burst generating O2- and H2O2, and these reactive oxygen intermediates (ROIs) cue the induction of defense genes and cell death in the development of a restricted lesion. This localized hypersensitive response (HR) is accompanied by the development of systemic acquired resistance to virulent pathogens. Here we show that inoculation of...

The high-affinity, type I lg Fc receptor (FcyRI) for human IgG1, human lgG3, murine IgGZa, and murine lgG3 is highly expressed on monocytes, neutrophils (PMN) in certain disease states, and phagocytes treated with interferon-y (IFN-7). We studied the activation of the human PMN oxidative burst and stimulated fluid pinocytosis induced by three monoclonal antibodies (MoAbs) directed against FcyRl...

Caspases are a family of cysteine proteases that play essential roles during apoptosis, and we presume some of them may also protect the cell from oxidative stress. We found that the absence of yeast caspase 1(Yca1)in Saccharomyces cerevisiae leads to a more intense burst of mitochondrial reactive oxygen species (ROS). In addition, compared to wild type yeast cells, the ability of yca1 mutant c...

Flow cytometric analysis provides a rapid screen for abnormalities of polymorphonuclear neutrophils (PMN) function and reflect their behavior in vivo more accurately. This review summarizes the major fluorescent probes used to study PMN oxidative burst and apoptosis using flow cytometry (FCM). We also provide examples of FCM studies in physiological and pathological situations, illustrating the...

Phagocytosis and oxidative burst are two major effector arms of innate immunity. Although it is known that both are activated by Toll-like receptors (TLRs) and Rac GTPases, how their strengths are controlled in quiescent and TLR-activated cells is not clear. We report here that TIPE2 (TNFAIP8L2) serves as a negative regulator of innate immunity by linking TLRs to Rac. TLRs control the expressio...

Despite the fundamental function of neutrophils (polymorphonuclear leukocytes (PMNs)) in innate immunity, their role in Escherichia coli K1 (EC-K1) -induced meningitis is unexplored. Here we show that PMN-depleted mice are resistant to EC-K1 (RS218) meningitis. EC-K1 survives and multiplies in PMNs for which outer membrane protein ...