Fc- and non-Fc-mediated phagocytosis of Borrelia burgdorferi by macrophages

The Fc receptor (FcR) for immunoglobulin has been assigned a major role in the ingestion of Borrelia burgdorferi, the Lyme disease spirochete, by macrophages. Yet macrophages readily take up and kill B. burgdorferi that have not been opsonized. By use of doubly-labeled macrophages infected with spirochetes and analyzed by confocal fluorescence microscopy, simultaneous localization of both FcR and spirochetes (opsonized and unopsonized) was quantified. After infection with unopsonized spirochetes, bacterial surface antigen and the FcR remained distinct, confirming the expectation that unopsonized uptake of B. burgdorferi is largely independent of the FcR. A similar lack of colocalization was seen when opsonized spirochetes were ingested by macrophages whose FcRs were sequestered by an immune complex-coated substrate. Furthermore, comparable efficiency of uptake was observed whether or not the FcR was engaged.

Acrodermatitis chronica atrophicans in the United States: clinical and histopathologic features of six cases

Acrodermatitis chronica atrophicans is a chronic cutaneous disease caused by the Lyme disease spirochete Borrelia burgdorferi. Acrodermatitis chronica atrophicans is endemic in some regions of Europe but is only rarely seen in the United States. This report describes the clinical and histopathologic findings in six cases of acrodermatitis chronica atrophicans seen at the Mayo Clinic between 1912 and 1961. Histologic differences between early and late phases of the disease were observed, and multisystemic symptoms consistent with chronic Lyme disease were documented in a subset of the patients. All five patients from whom biographical data were available were European immigrants. Our data suggest that some of the first patients with Lyme disease in the United States came to the Mayo Clinic earlier in this century.

Tyrosine phosphorylation in activated human neutrophils. Comparison of the effects of different classes of agonists and identification of the signaling pathways involved

The tyrosine phosphorylation responses initiated in human neutrophils by soluble and particulate agonists were characterized. Chemotactic factors, hematopoietic growth factors, and inflammatory microcrystals stimulated in a time- and concentration-dependent manner the tyrosine phosphorylation of distinct patterns of substrates: pp120, pp85, pp70, and pp60 in the case of chemotactic factors; pp155, pp130, pp120, pp85, pp60, and pp40 in the case of granulocyte macrophage-CSF; and pp130, pp120, pp70, and pp60 in the case of monosodium urate (MSU) crystals. Several of the single bands on one-dimensional blots (including pp40, pp70, and pp120) could be resolved into multiple spots on two-dimensional gels. The responses of several other chemotactic factors resembled those of FMLP. Cytokineplasts retained the capacity to respond to FMLP, granulocyte-macrophage-CSF, or MSU crystals with a stimulation of tyrosine phosphorylation, and contained the major substrates detected in intact neutrophils. Several unrelated tyrosine kinase inhibitors (herbimycin A, genistein, and erbstatin) strongly diminished the tyrosine phosphorylation response to chemotactic factors. Pertussis toxin abrogated the tyrosine phosphorylation response to FMLP, whereas protein kinase C (Ro 21-8220, chelerithryn) inhibitors were without effect. Chelation of intracellular calcium attenuated the tyrosine phosphorylation response to FMLP. These results indicate that G proteins play a crucial role in the coupling of chemotactic factor receptors to tyrosine phosphorylation and that this coupling occurs in parallel to that of phospholipase C. These results also underline the complexity of the transduction pathways implicated in the initiation of tyrosine phosphorylation.

Tyrosine phosphorylation in activated human neutrophils. Comparison of the effects of different classes of agonists and identification of the signaling pathways involved

The tyrosine phosphorylation responses initiated in human neutrophils by soluble and particulate agonists were characterized. Chemotactic factors, hematopoietic growth factors, and inflammatory microcrystals stimulated in a time- and concentration-dependent manner the tyrosine phosphorylation of distinct patterns of substrates: pp120, pp85, pp70, and pp60 in the case of chemotactic factors; pp155, pp130, pp120, pp85, pp60, and pp40 in the case of granulocyte macrophage-CSF; and pp130, pp120, pp70, and pp60 in the case of monosodium urate (MSU) crystals. Several of the single bands on one-dimensional blots (including pp40, pp70, and pp120) could be resolved into multiple spots on two-dimensional gels. The responses of several other chemotactic factors resembled those of FMLP. Cytokineplasts retained the capacity to respond to FMLP, granulocyte-macrophage-CSF, or MSU crystals with a stimulation of tyrosine phosphorylation, and contained the major substrates detected in intact neutrophils. Several unrelated tyrosine kinase inhibitors (herbimycin A, genistein, and erbstatin) strongly diminished the tyrosine phosphorylation response to chemotactic factors. Pertussis toxin abrogated the tyrosine phosphorylation response to FMLP, whereas protein kinase C (Ro 21-8220, chelerithryn) inhibitors were without effect. Chelation of intracellular calcium attenuated the tyrosine phosphorylation response to FMLP. These results indicate that G proteins play a crucial role in the coupling of chemotactic factor receptors to tyrosine phosphorylation and that this coupling occurs in parallel to that of phospholipase C. These results also underline the complexity of the transduction pathways implicated in the initiation of tyrosine phosphorylation.

Misoprostol stimulates leukocyte cyclic adenosine 3',5' monophosphate production and synergizes with colchicine: novel combination of established drugs may boost anti-inflammatory potential

Elevation of intracellular cyclic adenosine 3',5' monophosphate (cAMP) inhibits various proinflammatory and immune responses of leukocytes. Among agents known to stimulate cAMP production in these cells, prostaglandins E (PGEs) have received particular attention as potential immunosuppressive and/or anti-inflammatory drugs. Their clinical use, however, is limited by poor oral absorption and extreme metabolic instability. Misoprostol, a synthetic analog of PGE1 that can be given orally and that has a significantly longer biological half-life, is now used to prevent or treat nonsteroidal anti-inflammatory drug (NSAID)-induced gastric injury. Because it might also exert anti-inflammatory effects on leukocytes, we have characterized the effects of misoprostol on cAMP production in these cells. We have found that misoprostol does stimulate cAMP production, although with some-what less potency and maximal effect than PGE1; this stimulation is synergistically increased by pretreatment of cells with colchicine; a clinically relevant dose of colchicine is effective given sufficient pretreatment time, and preexposure of cells to colchicine enables a clinically relevant dose of misoprostol to stimulate cAMP generation. We conclude that colchicine and misoprostol represent a drug combination that might prove clinically useful for therapy of inflammatory disease.

Target imbalance: disparity of Borrelia burgdorferi genetic material in synovial fluid from Lyme arthritis patients

Lyme arthritis is a late manifestation of Lyme disease that results in episodic synovial inflammation and swelling. Although this process is thought to be driven directly by the spirochetal etiologic agent, Borrelia burgdorferi, the organism itself has been recovered by culture only twice. In contrast, polymerase chain reaction (PCR) studies are usually positive. This apparent discrepancy in 19 culture-negative synovial fluid specimens from 18 patients with Lyme arthritis was investigated. In all 19, DNA sequences characteristic of plasmid-encoded genes OspA and OspB were easily detected. However, despite equivalent or even superior analytic sensitivity for detection of cultured organisms, the reactivity of two genomic DNA targets was often weak or absent altogether in the clinical specimens. This apparent overrepresentation of B. burgdorferi plasmid sequences was found exclusively in clinical specimens and not in cultured organisms. The physiologic imbalance of genomic and plasmid DNA reactivity in B. burgdorferi infection may signal an underlying pathogenetic mechanism.

Circulating Borrelia burgdorferi in patients with acute Lyme disease: results of blood cultures and serum DNA analysis

To determine the usefulness of blood culture and polymerase chain reaction (PCR) analysis in detecting circulating Borrelia burgdorferi or its DNA, blood and serum from untreated patients with acute Lyme disease were examined. None of the cultures of blood or serum from the 7 patients tested demonstrated spirochetes. Similarly, all patient serum samples, assayed in two laboratories, were negative for B. burgdorferi DNA using PCR amplification. These results suggest that in patients with acute Lyme disease, spirochetes, spirochete DNA, or both circulate early, only intermittently, or at low levels and that neither culture nor PCR testing of blood or serum, as currently done, appears likely to prove generally useful in the diagnosis of Lyme disease.

Heat shock in human neutrophils: superoxide generation is inhibited by a mechanism distinct from heat-denaturation of NADPH oxidase and is protected by heat shock proteins in thermotolerant cells

Independently of the stimulating agent used, generation of O2- by human neutrophils is transiently inhibited when the cells have been exposed to elevated temperatures. This phenomenon is concomitant with the synthesis of heat shock proteins (HSPs). We have investigated a possible relationship between HSPs and modulation of NADPH oxidase activity in human neutrophils exposed to heat. HSPs were not involved in the inhibition of O2- generation since 1) in enucleated cytoplasts, which are unable to synthesize proteins, the generation of O2- was inhibited after exposure to 43 degrees C, 2) using actinomycin D (Act D) in intact cells, it was possible selectively to inhibit the synthesis of HSPs without modifying the inhibition of NADPH oxidase activity that followed HS. Furthermore, the recovery of NADPH oxidase activity was not under the control of HSPs because the enzyme recovered as well in Act D-treated neutrophils. The NADPH oxidase activity was reconstituted in a cell-free assay by combining the cytosol with the plasma membrane-enriched fraction in the presence of arachidonic acid (AA) and NADPH. Subcellular fractions obtained from control or heated neutrophils exhibited similar oxidase activities suggesting that heat exposure did not induce denaturation of the oxidase components but rather altered the mechanisms of translocation and/or assembly of these components with the plasma membrane. This hypothesis was supported by the inhibition of the granule release in heated cells, a process which also requires translocation and association fusion with the plasma membrane. On the other hand, preexposure of neutrophils to HS prevented the inhibition of O2- generation during a second challenging HS. This acquired thermotolerance was abolished when the synthesis of HSPs was inhibited during the first HS with Act D, indicating a direct relationship between protection of O2- generation and synthesis of HSP. Here we demonstrate that synthesis of HSPs and inhibition or recovery of NADPH oxidase activity are concomitant but unrelated phenomena. In contrast, accumulation of HSPs in thermotolerant neutrophils appeared to play an important role in the prevention of NADPH oxidase inhibition. These results provide further insights into the behavior of human neutrophils and NADPH oxidase upon heat injury.

The fate of Borrelia burgdorferi, the agent for Lyme disease, in mouse macrophages. Destruction, survival, recovery

The macrophage is a known reservoir for a number of infectious agents, and is therefore a likely candidate site for persistence of Borrelia burgdorferi, the Lyme spirochete. We report that unopsonized B. burgdorferi enter macrophages rapidly, resulting mainly in degradation but occasionally in apparent intracellular persistence. We studied uptake of spirochetes by macrophages by simultaneously labeling infected cells with antibodies to B. burgdorferi and with sequential components of the endocytic pathway, and we examined optical sections (0.5-1.0 micron in thickness) of these cells by confocal fluorescence microscopy at multiple time points after infection. We found that only 5 min of incubation at 37 degrees C were required for nearly 100% of B. burgdorferi to enter a lysosomal glycoprotein-positive compartment, whereas 60 min were required for 90% of the spirochetes to appear in a cathepsin L-positive compartment under the same conditions. We also labeled infected living cells with acridine orange to distinguish live from killed intracellular organisms. Although the large majority of spirochetes within a given cell were dead, we saw occasional live ones up to 24 h (the longest interval examined) after all extracellular organisms had been lysed in distilled water. Moreover, we can reculture spirochetes from macrophages after infection. Persistence of spirochetes within macrophages provides a possible pathogenetic mechanism for chronic or recurrent Lyme disease in man.

The fate of Borrelia burgdorferi, the agent for Lyme disease, in mouse macrophages. Destruction, survival, recovery

The macrophage is a known reservoir for a number of infectious agents, and is therefore a likely candidate site for persistence of Borrelia burgdorferi, the Lyme spirochete. We report that unopsonized B. burgdorferi enter macrophages rapidly, resulting mainly in degradation but occasionally in apparent intracellular persistence. We studied uptake of spirochetes by macrophages by simultaneously labeling infected cells with antibodies to B. burgdorferi and with sequential components of the endocytic pathway, and we examined optical sections (0.5-1.0 micron in thickness) of these cells by confocal fluorescence microscopy at multiple time points after infection. We found that only 5 min of incubation at 37 degrees C were required for nearly 100% of B. burgdorferi to enter a lysosomal glycoprotein-positive compartment, whereas 60 min were required for 90% of the spirochetes to appear in a cathepsin L-positive compartment under the same conditions. We also labeled infected living cells with acridine orange to distinguish live from killed intracellular organisms. Although the large majority of spirochetes within a given cell were dead, we saw occasional live ones up to 24 h (the longest interval examined) after all extracellular organisms had been lysed in distilled water. Moreover, we can reculture spirochetes from macrophages after infection. Persistence of spirochetes within macrophages provides a possible pathogenetic mechanism for chronic or recurrent Lyme disease in man.

Cytokineplasts and U-cytoplasts from human polymorphonuclear leukocytes: role of granule-poor motile fragments in the analysis of cell physiology

We have been using granule-poor anucleate fragments--cytokineplasts and U-cytoplasts--released from human peripheral blood polymorphonuclear leukocytes (granulocytes; PMN) to study cell functions that bear on aspects of the inflammatory response. The work is particularly aimed at the relationships among specific but overlapping areas of leukocyte activity: adherence, locomotion, target recognition, chemotaxis, penetration of endothelial monolayers, ingestion, the increased metabolic activity that ordinarily accompanies phagocytosis or other cell activation processes, degranulation of lysosomal structures, and intracellular killing. The ways in which these activities can be separated from one another may distinguish obligate interactions from mere concomitance, and may reveal the specific pathways by which cell function is altered. We have found that cytoplasts provide a unique way of looking at the composition and function of the cell's motile and killing machinery, in greatly simplified systems.

Evidence for reactive nitrogen intermediates in killing of staphylococci by human neutrophil cytoplasts. A new microbicidal pathway for polymorphonuclear leukocytes

In anucleate, granule-poor, motile fragments from human blood neutrophils (cytokineplasts; CKP), the nitric oxide synthase inhibitor N omega-monomethyl-L-arginine (NMMA) produced a modest decrease in uptake of staphylococci from supernatants (P less than 0.02, n = 7), and a marked decrease in the killing of cytoplast-associated bacteria (P less than 0.001, n = 7). After 60 min of incubation with bacteria, NMMA-treated cytoplasts had a mean of over 3.5 times as many live, CKP-associated staphylococci as did controls (51% of the inocula versus 14%), despite having taken up fewer. Effects on both uptake and killing were reversible by L-arginine but not by D-arginine. Results were the same with other granule-poor cytoplasts (U-cytoplasts, U-CYT), which, unlike CKP, retain activatable oxidase activity. Killing by intact PMN, including those from a patient with chronic granulomatous disease, was not inhibited by NMMA. Thus, the ability to discern effects of NMMA correlated with the paucity of granules, without regard to the presence or absence of activatable oxidase. We propose that the generation of reactive nitrogen intermediates serves as an additional microbial killing pathway in PMN, and that cytoplasts can be used to help delineate the spectrum of susceptible targets.

Identification of a thermolabile component of the human neutrophil NADPH oxidase. A model for chronic granulomatous disease caused by deficiency of the p67-phox cytosolic component

Mild heating of human neutrophils inactivates the respiratory burst oxidase, producing a defect in superoxide production and bacterial killing comparable to that seen in patients afflicted with chronic granulomatous disease (CGD). We have now investigated the mechanism and specificity of this inactivation by examining the effect of mild heating on the known oxidase components: the membrane-bound subunits of the cytochrome b558 (gp91-phox and p22-phox) and the two cytosolic oxidase factors (p47-phox and p67-phox). Heating (46 degrees C for 7.5 min) caused intact neutrophils to lose greater than 85% of their capacity to produce superoxide, a defect which was localized to the cytosolic, but not the membrane, fraction. Complementation studies with CGD cytosols deficient in either p47-phox or p67-phox suggested that the defective component of heat-inactivated cytosol was p67-phox. This was confirmed by experiments showing that recombinant p67-phox, but not p47-phox, exhibited lability at 46 degrees C and completely reconstituted oxidase activity of heat-treated cytosol. These studies indicate that mild heating of either intact neutrophils or normal neutrophil cytosol results in a selective inactivation of p67-phox, providing a model oxidase system for the extremely rare p67-phox-deficient form of CGD.

Protein kinase C isoforms in human neutrophil cytoplasts

Granule-poor human neutrophil cytoplasts, prepared without heat or cytochalasin B treatment so as to preserve both motile function and activatable respiratory burst oxidase, were investigated for their content of several isoforms of protein kinase C (PKC). Immunoblotting with isoform-specific rabbit antibodies (Abs) to PKC revealed that both the alpha-specific and the beta(I and II)- specific Abs recognized a protein band of 78 kd comigrating with PKC from rat brain cytosol. The gamma-specific antiserum did not detect any protein of this molecular mass. The cytoplast beta-PKC band was more readily detected than the cytoplast alpha-PKC band. Antibodies to beta I- or beta-II- specific PKC sequences showed the beta II subtype to be the predominant form of beta-PKC, although some beta I was also found. The identity of the 78-kd cytoplast bands as PKC was established by the fact that phorbol ester treatment of intact cytoplasts induced translocation of the bands from cytosol to membrane fractions. However, whereas PKC specific activity was similar in cytoplast lysates and brain cytosol, immunoreactivity of cytoplast alpha- and beta-PKC bands was considerably less than that of rat brain. Hydroxylapatite chromatography of partially purified cytoplast PKC revealed two major peaks of PKC activity precisely coeluting with brain alpha- and beta-PKC and displaying comparable enzymatic activities despite the relatively weak immunoreactivity of cytoplast alpha- and beta-PKC. To our knowledge, this is the first demonstration that human neutrophil-derived cytoplasts contain alpha, beta I, and beta II forms of PKC and that each isoform translocates from cytosol to membrane upon exposure to phorbol ester at concentrations that induce superoxide production. In addition, our evidence raises the possibility that cytoplasts may also possess other isoforms of PKC that we are unable to detect with our alpha, beta, and gamma antibodies. Finally, the granule-poor cytoplasts seem a particularly useful preparation in which to examine the role of individual PKC isoforms in neutrophil activation.

Photopheresis for rheumatoid arthritis

For rheumatoid arthritis, an effective therapy with minimal toxicity would be welcome. In a six-month pilot study of seven patients with a variety of presentations and previous treatments, we tested a therapy involving the extracorporeal photoactivation of biologically inert methoxsalen (8-methoxypsoralen) by ultraviolet A energy to a form that covalently cross-links lymphocyte DNA; the injured cells are returned to the patient. Prior experimental studies had indicated that this regimen produces an immune reaction against antigens on treated T Cells, and a clinical trial in cutaneous T cell lymphoma had been successful. The current patients were treated on two successive days monthly (or, later on, biweekly). Between 12 and 16 weeks of therapy there appeared to be a breakpoint after which joint counts and joint scores of four patients began to improve. In three of them, these measures eventually diminished by mean values of 71% and 80%, respectively, of their baseline values, along with variable improvement in less direct indicators of clinical response. The joints of the fourth patient improved modestly (by 33% and 59%, respectively, of baselines) but he required alternative therapy, and those of the remaining three patients did not improve. Mean slopes for the joint counts were significantly different from zero after the apparent breakpoint (but not before), whether one examined the four apparent responders (p = 0.01) or the entire group of seven (p = 0.01). After completion of therapy, there was also a delay, of two to three months, in the clinical deterioration of those who had improved. There was only one mechanical adverse effect--a single episode of transient hypotension in 102 treatment sessions--and no toxic ones. This preliminary study suggests that extracorporeal photochemotherapy may be effective at least in the short term in certain patients with rheumatoid arthritis, with less apparent toxicity than that of any of the drugs currently used for this disorder. It deserves further evaluation.

Cryopreserved cytoplasts from human neutrophils migrate across monolayers of human endothelial cells in response to a chemoattractant gradient

We have measured the capacity of two types of granule-poor anucleate cytoplasmic fragments (cytoplasts) from human polymorphonuclear leukocytes (PMN) to migrate across the barrier imposed by monolayers of human umbilical vein endothelial cells (EC) with and without chemotactic stimulation by fMLP. Cytoplasts were made by brief heating of PMN attached to surfaces (CKP) or by discontinuous gradient centrifugation (U-CYT). In the absence of chemoattractant, both types of cytoplast adhered poorly to endothelial cell monolayers, as did unstimulated intact PMN from which the cytoplasts were derived. In the presence of a transendothelial chemoattractant gradient both types of cytoplast exhibited a marked increase in adherence to, and migration across, endothelial monolayers; CKP did so to the same extent as chemoattractant-stimulated intact PMN. Since these motile cytoplasts are markedly deficient in most cytoplasmic organelles they may serve as useful tools for the dissection of cellular mechanisms that mediate PMN migration across endothelia.

Cryopreserved cytoplasts from human polymorphonuclear leukocytes (cytokineplasts) are chemotactic at speeds comparable to those of fresh intact cells

Cytokineplasts (CKP) are granule-poor cytoplasts from human polymorphonuclear leukocytes (PMN) that retain motile function, even (unlike the parent PMN) after cryopreservation. Employing time-lapse videomicroscopy, we examined the chemotactic properties of CKP after cryopreservation toward erythrocytes lysed by laser microirradiation. Paths of locomotion were plotted for six CKP in the field, and velocities were calculated at 10-sec intervals. Mean velocities of the six fragments, ranging from 9.3 to 20.8 microns/min, are of the order of fresh, intact PMN, the fastest of locomoting cells.

Treatment of rheumatoid arthritis by extracorporeal photochemotherapy. A pilot study

In a 6-month pilot study of 7 patients with rheumatoid arthritis, we tested a treatment involving the extracorporeal photoactivation of biologically inert methoxsalen (8-methoxypsoralen) by ultraviolet A energy to a form that covalently cross-links lymphocyte DNA; the injured cells are reinfused into the patient. Prior experimental studies had indicated that this regimen produces an immune reaction against antigens on treated T cells, and a clinical trial in patients with cutaneous T cell lymphoma had been successful. The current study patients were treated monthly, on 2 successive days (or biweekly, later on). Between 12 and 16 weeks of therapy, there appeared to be a breakpoint, after which the joint counts and joint scores of 4 of the patients began to improve. In 3 of the 4 patients, these measures eventually diminished by a mean of 71% and 80% of baseline values, respectively, and there was variable improvement in less direct indicators of clinical response. The joint counts and scores of the fourth patient improved modestly (by 33% and 59% of baselines, respectively) but he required alternative therapy, and those of the remaining 3 study patients did not improve. Mean slopes for the joint counts were significantly different from zero after the apparent breakpoint (but not before), whether one examined the 4 apparent responders (P = 0.01) or the entire group of 7 patients (P = 0.01). After completion of therapy, there was also a delay, of 2-3 months, in the clinical deterioration of those patients who had improved. There was only 1 mechanical adverse effect--a single episode of transient hypotension in 102 treatment sessions--and no toxic effects.(ABSTRACT TRUNCATED AT 250 WORDS)

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