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J E Cutler

Publications and source records attributed to J E Cutler.

At least 37 records · Page 2Linked to original sources
PubMed1998

Antibody and/or cell-mediated immunity, protective mechanisms in fungal disease: an ongoing dilemma or an unnecessary dispute?

Historically there has been controversy on the relative importance of antibody- and cell-mediated immune responses in the protection against fungal pathogens. The controversy was fuelled by the difficulties encountered in obtaining consistent results with polyclonal antibody experiments and I inducing long-lasting immune protection by vaccinations with induce stron cell-mediated responses. Recent studies indicate that both antibody- and cell-mediated immune responses can contribute to host protection against Candida albicans and C. neoformans. At the present time the major issue is not the relative importance of antibody- and cell-mediated immune responses but rather, the mechanisms by which the two arms of the immune system function and cooperate.

Animals↗
PubMed1997

Assessment of a mouse model of neutropenia and the effect of an anti-candidiasis monoclonal antibody in these animals.

As previously reported, monoclonal antibody (MAb) B6.1 increases resistance to hematogenous disseminated candidiasis in normal and SCID mice. In this study, MAb B6.1 was examined in a mouse model of neutropenia. The neutropenia was induced for a short period of time by a single dose of the anti-neutrophil antibody, MAb RB6-8C5, or for a protracted period by doses of MAb RB6-8C5 every other day. At low doses (< or = 25 microg/mouse), neutrophils were primarily affected, but at high doses (> or = 50 microg/mouse), lymphocytes were also depleted. Mice given either single or multiple doses of MAb RB6-8C5 were more resistant to experimental hematogenous disseminated candidiasis if they received MAb B6.1 before and after challenge with Candida albicans yeast cells intravenously. These results show the utility of MAb RB6-8C5 for induction of a protracted neutropenia in mice and demonstrate that MAb B6.1 can enhance resistance against candidiasis under neutropenic conditions.

Animals↗
PubMed1997

Biochemical characterization of Candida albicans epitopes that can elicit protective and nonprotective antibodies.

We previously reported that the immunoglobulin M (IgM) monoclonal antibody (MAb) B6.1 protects mice against disseminated candidiasis, whereas the IgM MAb B6 does not. Both MAbs are specific for an adhesin fraction isolated from the cell surface of Candida albicans, but their epitope specificities differ. In the present study, we examined the surface locations of both epitopes and obtained structural information regarding the B6.1 epitope. Immunofluorescence confocal microscopic analysis of C. albicans yeast forms showed that epitope B6.1 is displayed rather homogeneously over the entire cell surface, whereas epitope B6 appears to have a patchy distribution. Both antibodies were essentially nonreactive with the surfaces of mycelial forms of the fungus, indicating that neither epitope is expressed on the surfaces of these forms. For isolation of the B6.1 epitope, the adhesin fraction consisting of cell surface phosphomannan was subjected to mildly acidic (10 mM HCl) hydrolysis and was fractionated into acid-labile and acid-stable portions by size exclusion chromatography. Antibody blocking experiments showed that the B6.1 epitope is an acid-labile moiety of the phosphomannan and that the B6 epitope is located in the acid-stable fraction. The B6 epitope appeared to be mannan because it was stable to heat (boiling) and protease treatments but was destroyed by alpha-mannosidase digestion. The B6.1 epitope eluted from the size exclusion column in two fractions. Mass spectroscopic analyses showed that one fraction contained material with the size of a mannotriose and that the other was a mixture of mannotriose- and mannotetraose-size substances. Dose response inhibition tests of the fractions indicated that the B6.1 epitope is associated with the mannotriose. Nuclear magnetic resonance (NMR) spectroscopic analysis of the epitope yielded data consistent with a beta-(1-->2)-linked mannotriose. The fine structure of the B6 epitope is under investigation. Information derived from these investigations will be useful both in understanding protective versus nonprotective antibody responses to C. albicans and in improving anti-Candida vaccine formulations.

Agglutination Tests↗
PubMed1997

A monoclonal antibody to Candida albicans enhances mouse neutrophil candidacidal activity.

A monoclonal antibody (MAb) to Candida albicans (MAb B6.1) that protects against candidiasis and the nonprotective MAb B6 were compared for ability to support neutrophil (polymorphonuclear leukocyte [PMN]) candidacidal activity. Both MAbs are immunoglobulin M, and each recognizes distinct C. albicans mannan cell wall determinants. PMN candidacidal activity was assessed by transmission electron microscopy and by an in vitro killing assay. The results indicated that MAb B6.1, but not MAb B6, enhances ingestion and killing of yeast cells by PMN in the presence of serum complement.

Animals↗
PubMed1997

Gamma interferon is not essential in host defense against disseminated candidiasis in mice.

In vitro studies have suggested a role for interferon gamma (IFN-gamma) in host defense against disseminated candidiasis, but in vivo studies are inconclusive. We utilized homozygous IFN-gamma knockout (GKO) mice to determine if the cytokine is essential in host defense against this disease. Genotypes of mice were determined by PCR with specific primers for the normal or disrupted IFN-gamma gene. The GKO status of the mice was confirmed by an enzyme-linked immunosorbent assay, which showed no detectable IFN-gamma produced by their splenocytes stimulated by concanavalin A. To test the susceptibility of GKO mice to candidiasis, the animals were infected either intravenously (i.v.) or intragastrically (i.g.) with Candida albicans. GKO mice infected i.v. survived as long as wild-type (WT) mice and showed no difference in Candida CFU counts in liver, spleen, or kidneys compared to those for WT mice. When animals were given Candida i.g., at 3 h or at 10 or 21 days after infection, there was no dissemination of Candida to the lung, liver, spleen, or kidneys for either GKO or WT mice. There was no difference in Candida CFU counts recovered from the stomach or intestines between GKO and WT mice. Histological examination of the stomach cardial-atrium fold, where the fungus was located, showed that GKO mice did not have evidence of more tissue damage or fungal invasion than WT mice. Finally, the jejunum for both types of mice showed no evidence of tissue damage or fungal invasion. These studies indicate that IFN-gamma is not essential in host defense against C. albicans that originates from a mucosal site or that is given directly into the bloodstream in a mouse model.

Animals↗
PubMed1995

Antibody response that protects against disseminated candidiasis.

We previously showed that surface mannans of Candida albicans function as adhesins during yeast cell attachment to mouse splenic marginal zone macrophages. The mannan adhesin fraction was encapsulated into liposomes and used to vaccinate mice over a 5- to 6-week period. Circulating agglutinins specific for the fraction correlated with increased resistance to disseminated candidiasis. Antiserum from vaccinated animals protected naive BALB/cByJ mice against C. albicans serotype A and B strains and Candida tropicalis. Antiserum also protected SCID mice against disseminated disease. The serum protective ability was stable at 56 degrees C, but this ability was adsorbed by C. albicans cells. The antiserum was divided into three fractions after separation by high-performance liquid chromatography. One fraction contained all of the agglutinin activity and transferred resistance to naive mice. A second fraction also transferred resistance. Two monoclonal antibodies (MAbs) specific for candidal surface determinants were obtained. MAb B6.1 is specific for a mannan epitope in the adhesin fraction, and MAb B6 is specific for a different epitope in the fraction. Both MAbs are immunoglobulin M, and both strongly agglutinate candidal cells, but only MAb B6.1 protected both normal and SCID mice against disseminated candidiasis. In one experiment, 10 normal mice were given MAb B6.1 and challenged with yeast cells. Six mice survived the 67-day observation period; 4 of the survivors were cured as evidenced by the lack of CFU in the kidney and spleen. Our studies show that antibodies against certain cell surface antigens of C. albicans help the host resist disseminated candidiasis.

Animals↗
PubMed1994

Elimination of mouse splenic macrophages correlates with increased susceptibility to experimental disseminated candidiasis.

To evaluate the role of macrophages in experimental disseminated candidiasis, mouse splenic macrophages were eliminated by i.v. delivery of liposome-entrapped dichloromethylene diphosphonate (L-Cl2MDP). Splenic tissue sections that were immunoperoxidase-stained with mAbs against marginal zone macrophages (MONTS-4), red pulp macrophages (SK39), and neutrophils (SK208) showed that 3 days after L-Cl2MDP treatment, macrophages but not neutrophils were depleted, and circulating neutrophils responded normally to an irritated peritoneum and showed normal phagocytic ability. That is, in response to thioglycollate in the peritoneum, neutrophils migrated in normal numbers to the peritoneal cavity and expressed the normal activation phenotype of high Mac-1 and low Mel-14 Ag levels. These neutrophils also showed normal ability to ingest Candida albicans yeast cells in both in vitro and in vivo assays. However, the spleens from L-Cl2MDP-treated mice lost their ability to bind yeast, which agrees with our previous findings that yeast cells bind specifically to marginal zone macrophages. When macrophage-depleted were systemically challenged with C. albicans, clearance of viable fungal elements from blood was slower, their kidneys had higher recoverable CFU, and both BALB/cByJ and congenitally thymic-deficient (nude) mouse strains did not survive as long as control mice. Mice given L-Cl2MDP recovered most of their macrophage function by 56 days and became normal in their resistance to C. albicans. These results indicate that macrophages play an important role in host resistance to experimental disseminated candidiasis, but the mechanism does not appear to involve T cell functions.

Animals↗
PubMed1994

Recurrent cardiac events in survivors of ventricular fibrillation or tachycardia. Implications for driving restrictions.

OBJECTIVE: To determine when survivors of ventricular tachycardia (VT) or ventricular fibrillation (VF) might most safely return to driving. DESIGN: Consecutive case series of 501 VT and VF survivors discharged alive between August 1978 and October 1989 and followed from 0 to 117 months (mean, 26 months). SETTING: Cardiac arrhythmia service of a university hospital. PATIENTS: The study group comprised 290 consecutive patients with sustained VT and 211 patients with VF who underwent electrophysiological studies and were discharged alive (78% male; mean age, 59 years). The mean ejection fraction (available in 338 patients) was 0.42. INTERVENTIONS: Antiarrhythmic drug testing for all patients was guided by serial electrophysiological testing. Overall, 227 patients (45%) were discharged on conventional antiarrhythmic agents, 115 (23%) on amiodarone, 39 (8%) received an implantable defibrillator, and 120 (24%) received no specific antiarrhythmic therapy. MAIN OUTCOME MEASURES: Main outcomes included any event that could hamper a patient's ability to operate a motor vehicle. Specifically, these events included recurrent VF, poorly tolerated, hemodynamically unstable VT, syncope, sudden cardiac death, and implantable defibrillator discharge. RESULTS: Event risks were assessed during the first year after hospital discharge because that is when most patients decide whether to begin driving again. The 1-year outcome event rate for all 501 patients was 17%. Three distinct periods of risk were identified. The monthly hazard rate was highest in the first month after hospital discharge (4.22% per month), intermediate in months 2 through 7 (1.81% per month), and lowest in months 8 through 12 (0.63% per month). The 191 patients for whom no successful conventional antiarrhythmic drug could be found during electrophysiological testing experienced a persistently high monthly event risk (1.6%) during months 8 through 12. CONCLUSIONS: All survivors of VT or VF should refrain from driving during the first month after hospital discharge when the hazard for events that could impair their ability to drive is greatest. Our data would support restricting driving for most patients until the eighth month after hospital discharge, when risk becomes lowest. Restriction might be lengthened in patients for whom electrophysiological testing finds no satisfactory conventional antiarrhythmic agent because their risk remains higher than average even after 7 months. Individualized recommendations should be allowed because the accident rate for patients who actually suffer sudden death is low.

Accidents, Traffic↗
PubMed1994

Evidence for adhesin activity in the acid-stable moiety of the phosphomannoprotein cell wall complex of Candida albicans.

Previously, we showed that Candida albicans hydrophilic yeast cells adhere specifically to mouse splenic marginal-zone macrophages. The adhesins are part of the yeast cell wall phosphomannoprotein complex, and one adhesin site, which reacts with the monoclonal antibody 10G, was identified as a beta-1,2-linked tetramannose in the acid-labile portion of the complex. We report here that the acid-stable part of the complex, which has not been reported previously to have adhesin activity, is in large part responsible for yeast cell binding to the splenic marginal zone. The phosphomannoprotein complex, termed Fr.II, was isolated from C. albicans serotype B yeast cells by beta-mercaptoethanol extraction and concanavalin A-agarose affinity chromatography. Fr.II is devoid of the serotype A-specific antigen factor 6, which functions in yeast cell attachment to epithelial cells. The acid-stable part of Fr.II (i.e., Fr.IIS) was obtained by mild acid hydrolysis and size exclusion fractionation. Fr.IIS was further fractionated into four fractions, Fr.IIS1, Fr.IIS2, Fr.IIS3, and Fr.IIS4, by concanavalin A-agarose column chromatography and elution with a linear gradient of alpha-methyl-D-mannopyranoside. Adhesin activity of these fractions was determined by their ability to block yeast cell binding to the splenic marginal zone. Fr.IIS1 and Fr.IIS2 yielded more material and stronger adhesin activity than either Fr.IIS3 or Fr.IIS4. Only Fr.IIS1 did not react with antibodies (anti-factor 5 and monoclonal antibody 10G) specific for the acid-labile beta-1,2-linked oligosaccharides. Fr.IIS1-coated latex beads attached specifically to the marginal zone in a pattern identical to that of yeast cell binding. Furthermore, Fr.IIS1-latex bead attachment was inhibited by soluble Fr.II or Fr.IIS. Initial chemical analyses indicate that the adhesin site on Fr.IIS1 is a carbohydrate because adhesin activity was destroyed by periodate oxidation but not by proteinase K digestion.

Adhesiveness↗
PubMed1994

Mouse sialoadhesin is not responsible for Candida albicans yeast cell binding to splenic marginal zone macrophages.

Candida albicans hydrophilic yeast cells specifically adhere to mouse macrophages in the splenic marginal zone and in lymph node subcapsular and medullary sinuses. These macrophages express sialoadhesin that binds erythrocytes, but binding of yeast cells is not mediated by sialoadhesin because (i) erythrocytes did not block yeast cell binding, (ii) yeast cell adherence was unaffected by sialoadhesin-specific monoclonal antibodies, (iii) the purified sialoadhesin did not bind to yeast cells, and (iv) an Fc-sialoadhesin chimera immobilized on plastic did not bind yeast cells. These data give further support for a unique macrophage adhesion system that binds C. albicans.

Adhesiveness↗
PubMed1993

Chemical definition of an epitope/adhesin molecule on Candida albicans.

An antigen (Ag), as defined by reactivity with a monoclonal antibody (mAb 10G), was found on the cell wall surface and on the plasma membrane of Candida albicans yeast cells (Li, R. K., and Cutler, J. E. (1991) J. Gen. Microbiol. 137, 455-464). The 10G Ag from the cell surface location was solubilized by treatment with beta-mercaptoethanol and Zymolyase. Antigenic activity of the extract was lost following periodate oxidation, but was stable to proteolytic enzyme and heat treatments. Mannoproteins in the extract were fractionated by hexadecyltrimethylammonium bromide. A fraction containing the 10G Ag was degraded by mild acid hydrolysis and a tetrahexose eluted from a P-2 size exclusion column was found to be the epitope (10G epitope) part of the 10G Ag. By use of gas-liquid chromatography, mass spectroscopy, and H-1 proton NMR analysis, the 10G epitope was determined to be a linear beta-1,2-linked tetramannose. The 10G Ag, which was immunopurified from the Zymolyase extract, and the 10G epitope were involved in the attachment of C. albicans to mouse spleen marginal zone macrophages. Both the 10G Ag and the purified 10G epitope specifically inhibited C. albicans adherence in an ex vivo binding assay. Latex beads adsorbed with the 10G Ag or the 10G epitope adhered specifically to the splenic marginal zone macrophages. These data show that a beta-1,2-linked mannotetraose part of a C. albicans cell wall mannoprotein is an adhesin site that may play a role in pathogenesis of disseminated candidiasis.

Animals↗
PubMed1993

Implantable cardioverter-defibrillator therapy in survivors of out-of-hospital sudden cardiac death without inducible arrhythmias.

OBJECTIVES: The aim of this study was to determine the efficacy of implantable cardioverter-defibrillator (ICD) therapy in survivors of sudden cardiac death in whom no ventricular arrhythmias can be induced with programmed electrical stimulation. BACKGROUND: Survivors of sudden cardiac death in whom ventricular arrhythmias cannot be induced with programmed electrical stimulation remain at risk for recurrence of serious arrhythmias. Optimal protection to prevent sudden death in these patients is uncertain. This study compares survival in the subset of survivors of sudden cardiac death with that of patients treated with or without an ICD. METHODS: A retrospective study was performed on 194 consecutive survivors of primary sudden death who had < or = 6 beats of ventricular tachycardia induced with programmed electrical stimulation with at least three extrastimuli. Ninety-nine patients received an ICD and 95 did not. RESULTS: There were no significant differences between the two groups in presenting rhythm, number of prior myocardial infarctions or use of antiarrhythmic agents. Patients treated with an ICD were younger (55 +/- 16 vs. 59 +/- 11 years, p = 0.03) and had a lesser incidence of coronary artery disease (48% vs. 63%, p = 0.04) and a lower ejection fraction (0.43 +/- 0.16 vs. 0.48 +/- 0.18, p = 0.04). There were no significant differences between the groups in the use of revascularization procedures or antiarrhythmic agents after the sudden cardiac death. Patients treated with an ICD had an improvement in sudden cardiac death-free survival (p = 0.04) but the overall survival rate did not differ from that of the patients not so treated (p = 0.91). A multivariate regression analysis that adjusted for the observed differences between the groups did not alter these results. CONCLUSIONS: Survivors of sudden cardiac death in whom no arrhythmias could be induced with programmed electrical stimulation remained at risk for arrhythmia recurrence. Although the proportion of deaths attributed to arrhythmias was lower in the patients treated with an ICD, this therapy did not significantly improve overall survival.

Actuarial Analysis↗
PubMed1993

Evidence that mannans of Candida albicans are responsible for adherence of yeast forms to spleen and lymph node tissue.

We have described a unique binding system between Candida albicans yeast-form cells and the marginal zone of mouse spleen (16). The chemical nature of the fungal adhesin(s) involved in this binding phenomenon was examined. A fraction obtained by 2-mercaptoethanol extraction (2-ME extract) of fungal cells caused a dose-response inhibition of yeast cell adherence to splenic marginal zone sites and also to subcapsular and medullary sinuses of mouse popliteal lymph nodes. Latex beads coated with the 2-ME extract showed a pattern of spleen and lymph node tissue binding identical to that observed with yeast cells. The extracted adhesins retained their binding activity in vivo. When 0.5 mg of the 2-ME extract was given intravenously to mice, spleen tissue removed up to 3 h later showed over 80% inhibition of yeast cell binding to the spleen marginal zone, and over 50% inhibition was retained for at least 24 h. The adhesins bound to a concanavalin A affinity column and were eluted by 0.5 M alpha-methyl-D-mannopyranoside, and the eluted adhesins were designated Fr.II. Fr.II was further fractioned by DEAE-Sephacel ion-exchange column chromatography, and one especially active and abundant fraction was designated Fr.IIa. The adhesin moiety appeared to be carbohydrate, because the activity of Fr.IIa was destroyed by 20 mM sodium periodate or by 5 U of alpha-mannosidase, but boiling (30 min) or proteinase K (100 micrograms/ml) treatments had no effect. Chemically, whereas the 2-ME extract contained significant amounts of protein and mannose, Fr.IIa consisted of over 98% mannose and less than 0.5% protein. These data strongly suggest that the mannan portion within a mannoprotein is responsible for the binding of yeast cells to splenic marginal zone and to subcapsular and medullary sinuses of mouse lymph node tissue.

Animals↗
PubMed1993

Binding of Candida albicans yeast cells to mouse popliteal lymph node tissue is mediated by macrophages.

We previously reported that Candida albicans yeast cells adhere to the macrophage-rich medullary and subcapsular sinus areas of mouse lymph node tissue. To determine whether the yeast cell-lymph node interaction is mediated by macrophages, the effect of specific elimination of macrophages on yeast cell binding was studied, and yeast cell adherence was correlated with the ingestion of India ink by lymph node cells. Macrophage elimination was done by use of liposome-containing dichloromethylene diphosphonate (L-Cl2MDP). Mice were injected in the hind footpads with the L-Cl2MDP preparation, popliteal lymph nodes were removed 5 days later, and yeast cell adherence was determined by an ex vivo binding assay. As controls, lymph nodes from mice that received footpad injections of either phosphate-buffered saline (PBS) alone or liposome-containing PBS were used. Use of macrophage- and neutrophil-specific monoclonal antibodies in tissue immunostaining showed that the L-Cl2MDP treatment eliminated macrophages but not neutrophils from the medullary and subcapsular sinus areas of the popliteal lymph nodes. A striking reduction of yeast cell adherence occurred with lymph nodes from L-Cl2MDP-treated mice compared with lymph nodes from control animals. The lymph node-yeast cell binding patterns of L-Cl2MDP-treated and control mice were the same regardless of mouse strain, sex, or T-cell competency. Results of India ink experiments, in which India ink was injected into footpads of mice and was rapidly taken up by popliteal lymph node macrophages, showed a strong correlation between yeast adherence and India ink staining of cells. In addition, the interaction of yeast cells with lymph node tissue from normal mice was not significantly affected by the addition of two extracellular matrix proteins, fibronectin and laminin, during the ex vivo adherence assay. These data indicate that medullary and subcapsular sinus lymph node macrophages express an adhesion system similar to that described for mouse splenic marginal zone macrophages.

Animals↗
PubMed1992

Evidence that Candida albicans binds via a unique adhesion system on phagocytic cells in the marginal zone of the mouse spleen.

We recently demonstrated by using an ex vivo adhesion assay that Candida albicans yeast cells exhibit a unique binding affinity for the marginal zone of the spleen. This binding event provides a working model for studying mechanisms of organ dissemination of the fungus from the blood. By using the ex vivo assays reported here, we showed by bright-field and electron microscopic techniques that mouse spleen marginal zone cells capable of ingesting India ink particles are also involved in yeast cell attachment. During splenic clearance of yeast cells from the circulation in vivo, C. albicans is also associated exclusively with marginal zone cells capable of ingesting India ink. The ability to ingest the ink particles is not necessarily related to yeast cell adherence, because the fungal cells did not bind to phagocytic cells in the splenic red pulp. In fact, the marginal zone phagocytic cells appear to have a unique binding system, because yeast cells also did not bind to phagocytes in other tissues, such as the thymus and peritoneum, or to seven different myeloid cell lines. In addition, antibodies to a number of well-characterized murine adhesion molecules, such as leukocyte integrins, LECAM-1, and CD44, had no effect on binding. On the basis of these results, we propose that splenic marginal zone phagocytes express a novel adhesion system that involves either a unique adhesion molecule or previously described adhesion molecules with unique binding activities.

Adhesiveness↗
PubMed1991

Improvements and important considerations of an ex vivo assay to study Candida albicans-splenic tissue interactions.

Improvements were made on an ex vivo assay to study adherence properties of Candida albicans to host internal organs. The assay is applicable to understanding mechanisms of C. albicans dissemination following a fungemia. Binding patterns of yeast forms to splenic tissue are intriguing and we found the following modifications to be especially relevant. Mice serving as spleen donors for the assay should be injected with 0.1 ml i.v. of a 10% concentration of luconyl blue, 5 min before killing. After collecting splenic sections on a glass slide, 100 microliters of a 1-2 x 10(8)/ml suspension of stationary yeast cells should be applied to the sections. The assay does not require a carbonate buffering system or serum supplements. Attachment of yeasts to host tissue occurs best if the interaction is allowed to proceed without agitation by rotation. Assessment of binding is facilitated by staining the slides with crystal violet and computer image analysis can be used for quantification of binding.

Animals↗