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D G Colley

Publications and source records attributed to D G Colley.

At least 55 records · Page 3Linked to original sources
PubMed1994

Activated T and B lymphocytes in peripheral blood of patients with Chagas' disease.

Whole blood preparations from patients with either the indeterminate (asymptomatic) or cardiac clinical forms of chronic Trypanosoma cruzi infection were analyzed by flow cytometry using double-labeling to identify subsets of circulating lymphocytes. Several significant differences were demonstrated between the blood lymphocyte profiles of chagasic patients and non-chagasic controls. Clear increase in the percentages and actual numbers of double-positive cells of the phenotype CD3+/HLA-DR+, as well as decrease in the percentage of CD45RA+/CD4+ and CD45RA+/CD8+ T cells, indicate greater numbers of activated T cells circulating in the blood of infected patients. Consistent parallel increases were seen also in the B lymphocyte subset which stained double-positive for CD19/CD5. There were no significant differences in the circulation of these chronic chagasic patients in the CD4:CD8 ratios. Also, no substantive phenotypic differences were observed in the lymphocyte populations between the two ends of the clinical spectrum (indeterminate versus cardiac) in chronic human Chagas' disease. These observations demonstrate that increased levels of activated T cells and CD5+ B cells are present in the circulation of people with chronic Chagas' disease. These are cell phenotypes that have been associated in other conditions with autoimmune, polyclonal, and hyperimmune responses. The specificities of these activated cells and the roles they may play in resistance or pathogenesis during chronic Chagas' disease need now to be determined.

Adult↗
PubMed1993

Priming immunization determines T helper cytokine mRNA expression patterns in lungs of mice challenged with respiratory syncytial virus.

Defining the mechanism for the vaccine-enhanced illness associated with respiratory syncytial virus (RSV) is critical for advancing RSV vaccine development. Previous studies in which infants were vaccinated with formalin-inactivated alum-precipitated whole virus did not protect from RSV infection, and those infected had a high incidence of severe illness. In contrast, previous clinical trials evaluating live attenuated RSV showed no associated vaccine-enhanced illness. We have used a mouse model to explore the immunopathogenesis of RSV infection. In this study cytokine mRNA expression was examined using 32P-labeled oligonucleotide probes in Northern blot analyses of polyA RNA extracted from lungs of mice primed with various vaccine preparations then challenged nasally with live RSV. We have shown that upon challenge, priming of mice with inactivated virus or subunit F glycoprotein induced a pattern of cytokine mRNA expression suggesting a dominant Th2-like lymphocyte response (relative increase in IL-4 mRNA expression). In contrast, challenge of mice primed with live RSV by parenteral or mucosal routes induced a Th1-like pattern of cytokine mRNA expression (relative decrease in IL-4 mRNA expression compared to IFN-gamma mRNA expression). Thus, the formulation and route of delivery of vaccine products can influence the pattern of cytokine expression in lung upon RSV challenge.

Animals↗
PubMed1993

Antibodies to Trypanosoma cruzi express idiotypic patterns that can differentiate between patients with asymptomatic or severe Chagas' disease.

Immunization of rabbits with pools of immunoaffinity-purified anti-Trypanosoma cruzi epimastigote antibodies derived from patients with different clinical forms of Chagas' disease induces antiidiotypic sera that can distinguish between anti-epimastigote antibodies from patients with asymptomatic (indeterminate (IND)) or severe (cardiac (CARD)) Chagas' disease. These idiotypically different anti-EPI antibodies from patients with the different clinical forms do not differ in their anti-epimastigote activities or isotypes. Analysis of immunoaffinity purified antibodies from individual chagasic patients by specific competitive ELISA generally confirms that Id-specific rabbit antisera can differentiate the clinical forms of the source of the antibodies. Based on these data, immunoaffinity-purified antibodies from patients share many Id with those from IND patients, although antibodies from IND patients express much lower levels of the distinctive Id characteristic of CARD patients. Reduction and alkylation of antibodies from IND patients reduces somewhat, but does not abolish, the ability of their Id to be recognized idiotypically, and to effectively inhibit in competitive ELISA. In contrast, reduction and alkylation of antibodies from CARD patients almost completely eliminates the ability of their predominant Id to be either recognized by, or inhibit, the appropriate systems. These data imply that the expression of the major Id that define CARD patients by these serologic anti-Id systems is largely dependent on the tertiary conformation of the Ig molecule. This agrees with our earlier studies on the respective differential abilities of CARD vs IND Id to stimulate anti-Id T cells by direct stimulation vs processing and presentation mechanisms.

Animals↗
PubMed1993

Amplification of a Trypanosoma cruzi DNA sequence from inflammatory lesions in human chagasic cardiomyopathy.

The major cause of morbidity and mortality in Chagas' disease is a chronic inflammatory cardiomyopathy, which presents ten or more years following initial infection. Demonstration of Trypanosoma cruzi in cardiac tissue by routine microscopy or culture is difficult in these patients, which has suggested that persistent organisms are not required for chronic disease. Consequently, studies have focused on elucidating an autoimmune pathogenesis of chronic injury. To further assess the persistence of T. cruzi in host tissue, DNA extracted from formalin-fixed, paraffin-embedded autopsy specimens from seronegative or seropositive patients was amplified by the polymerase chain reaction using T. cruzi-specific primers. Trypanosoma cruzi DNA sequences were not consistently amplified from four seropositive patients who lacked evidence of fatal chronic chagasic cardiomyopathy (CCC) (0 positive of 12 heart samples, 0 positive of four gonadal samples, and 0 positive of four adrenal samples) or nine seronegative patients (0 positive of 27 heart samples, 0 positive of nine gonadal samples and 0 positive of nine adrenal samples). In seven seropositive patients with severe CCC, cardiac tissue adjacent to inflammatory infiltrates yielded amplified T. cruzi DNA sequences in 18 of 21 heart samples. Parallel testing of gonadal and adrenal tissues from these same patients produced detectable T. cruzi DNA in none of the gonadal tissue samples and one of the seven adrenals. Our studies demonstrate that T. cruzi, or a portion of its genome, is present in the inflammatory lesion of chronic cardiac Chagas' disease.

Adult↗
PubMed1993

Characterization of inflammatory infiltrates in chronic chagasic myocardial lesions: presence of tumor necrosis factor-alpha+ cells and dominance of granzyme A+, CD8+ lymphocytes.

The inflammatory infiltrates in the heart lesions of chronic chagasic cardiomyopathy are composed predominantly of small lymphocytes with admixed macrophages, plasma cells, and segmented leukocytes. The phenotypes of the lymphoid cells in these infiltrates of human Chagas' disease have not been previously detailed. We used a panel of monoclonal and polyclonal antibodies to immunohistochemically characterize the inflammatory cells in frozen and fixed cardiac tissues from autopsied patients with severe chronic chagasic cardiomyopathy. In all cases, the inflammatory lesions were dominated by CD8+ lymphocytes, many of which expressed granzyme A. A few macrophage-like cells that expressed tumor necrosis factor-alpha were observed in each case. Relatively few natural killer cells or B lymphocytes were found in the lesions. These findings in human chagasic lesions are compatible with concepts that involve cytolysis and fibrosis, and new experimental findings that emphasize potential roles for CD8+ T cells in Chagas' disease.

B-Lymphocytes↗
PubMed1993

Expression of major histocompatibility complex antigens and adhesion molecules in hearts of patients with chronic Chagas' disease.

We have previously reported that heart lesions in patients with chronic cardiac Chagas' disease are composed predominantly of granzyme A+, cytolytic CD8+ T lymphocytes. We now pursue this study in the immunopathology of chronic chagasic cardiomyopathy by investigation of the expression of HLA antigens, and adhesion molecules in the hearts of seven chagasic patients with cardiac disease, two asymptomatic chagasic patients, and seven normal controls. Comparative immunohistochemical analyses show that HLA-ABC antigen expression is enhanced on the myocardial cells of chagasic patients with chronic cardiomyopathy, suggesting a possible role for these cells as targets for the CD8+ cytolytic lymphocytes dominant in these lesions. The HLA-DR antigens are not observed on myocardial cells, but are consistently upregulated on the endothelial cells in the hearts of patients with chronic chagasic cardiomyopathy. Intercellular adhesion molecule is expressed by endothelial cells of both chagasic and nonchagasic individuals, but E-selectin was detected only on vessels of hearts from chagasic patients who had chronic cardiomyopathy. Most of the lymphocytes in these lesions express lymphocyte function antigen-1 (LFA-1), CD44, and very late antigen-4, and a few display weak expression of LFA-3. We propose that the expression of these adhesion molecules and major histocompatibility complex antigens by endothelial cells, myocardial cells, and lymphoid cells in these lesions contribute to the pathogenesis of chronic chagasic cardiomyopathy.

Adult↗
PubMed1993

Two distinct pathological syndromes in male CBA/J inbred mice with chronic Schistosoma mansoni infections.

Humans chronically infected with Schistosoma mansoni most commonly present with the relatively asymptomatic intestinal form of the disease, whereas a small minority develop hepatosplenism characterized by severe hepatic disease with portal hypertension. Investigation of hypotheses describing the pathogenic mechanisms underlying the clinical forms of the human disease has been limited by the absence of an animal model that predictably develops such a spectrum of disease. We report that inbred male CBA/J mice that are chronically infected with S. mansoni develop two distinct syndromes, hypersplenomegaly syndrome (HSS) and moderate splenomegaly syndrome (MSS). Pathologically and immunologically, MSS and HSS remarkably parallel the intestinal and hepatosplenic clinical forms, respectively, in humans. HSS affects approximately 20% of these mice and consists of massive splenomegaly, ascites, thymic atrophy, severe anemia, and cachexia. The remaining majority of mice with MSS develop moderate splenomegaly only. Histopathological features of HSS include 1) relatively extensive hepatic fibrosis and granulomatous inflammation, 2) splenic congestion, 3) lymph node plasmacytosis, and 4) worms and eggs in the pulmonary vasculature. Immunologically, the idiotypes present on antisoluble egg antigen antibodies from HSS mice are distinct from those from mice with acute infections or the chronic MSS infection. These idiotypic differences are similar to those observed in patients with intestinal and hepatosplenic forms of the disease and may have regulatory importance. Investigation of the cellular and molecular events that lead to the development of MSS and HSS may advance current understanding of the pathogenesis of the clinical forms of chronic schistosomiasis in humans.

Animals↗
PubMed1992

In vivo molecular analysis of lymphokines involved in the murine immune response during Schistosoma mansoni infection. II. Quantification of IL-4 mRNA, IFN-gamma mRNA, and IL-2 mRNA levels in the granulomatous livers, mesenteric lymph nodes, and spleens during the course of modulation.

Parasite egg-induced granulomas are the primary pathogenic lesions in murine schistosomiasis mansoni. This cell-mediated granulomatous response is specific for soluble egg Ag and appears to be mediated predominantly by CD4+ Th2 cells. As infection progresses from the acute to the chronic phase, the cell-mediated anti-soluble egg Ag responses attenuate in a process termed modulation. In this study the hypothesis that modulation is effected by a chronic phase increase in Th2-inhibiting Th1 cell activity was investigated. Northern blot quantification of mRNA specific for the Th2 lymphokine, IL-4, and the Th1 lymphokines, IFN-gamma and IL-2, in the spleens, mesenteric lymph nodes, and granulomatous livers of mice infected for various lengths of time over the course of modulation was performed. Also, the capacity of mitogen- and Ag-stimulated spleen cells to produce message for these lymphokines was compared. Peak tissue levels of both IL-4 mRNA and IFN-gamma mRNA were seen in acutely infected mice, and levels of both messages declined as infection became chronic. Stimulated spleen cells from acutely infected mice also produced higher levels of IL-4 and IFN-gamma mRNA than cells from chronically infected mice. IL-2 mRNA was never detected in any tissue sample but was detected in the stimulated spleen cells, again with acute phase levels higher than chronic phase levels. Hence, this study shows no evidence for increased Th1 cell activity during chronic infection and suggests that modulation may be effected by a generalized suppression of lymphokine synthesis.

Animals↗
PubMed1992

Schistosoma mansoni: mortality, pathophysiology, and susceptibility differences in male and female mice.

In parallel studies of Schistosoma mansoni infections in male and female CBA/J mice, major sex-related differences are seen in the development of infection and disease. Upon equal subcutaneous exposures to 45 cercariae female mice present a more severe clinical course with consequent higher mortality than male mice. By 12 weeks of infection, more than 80% of female mice die, while less than 20% of infected males succumb to infection. This greater index of mortality is apparently due to the higher susceptibility of female mice to the development of adult worms. Exposed to 45 cercariae, virtually all females develop patent infections, but 8-34% of male mice do not do so. Also, the recovery rate of adult worms per cercariae from female mice is much higher than that from males, indicating that schistosomula are more successful in developing into adult worms in female mice. Additional studies indicate that this dichotomy of schistosomiasis in the sexes is not restricted to mice of the CBA/J strain, but also occurs in C57BL/6 and outbred CF1 strain mice.

Animals↗
PubMed1992

Immune responses during human schistosomiasis mansoni. XVIII. Immunologic status of pregnant women and their neonates.

The immune status of peripheral blood mononuclear cells (PBMC) and sera of pregnant women infected with the helminth Schistosoma mansoni was studied during pregnancy and the cord blood mononuclear cells (CBMC) and sera from their offspring were studied at parturition. PBMC pokeweed mitogen-induced responses were maintained in gravid women, but the responses to both schistosome and non-schistosome antigenic preparations declined progressively during pregnancy. Schistosomal antigens stimulated proliferative responses by the CBMC of many neonates born of infected mothers, but not those of uninfected mothers. These specific responses by CBMC of only neonates born of infected mothers are indicative of in utero, cell-mediated sensitization of the neonates, which could be due either to circulating schistosomal antigens or to anti-idiotypic antibodies which cross the placenta during gestation. Sera from infected mothers and the cord blood sera from their babies showed the same levels of specific IgG anti-schistosomal activity. Anti-schistosomal IgM levels were maintained during pregnancy to some antigens and not to others, while such antibodies were rarely found in cord blood sera, and then only at very low levels.

Animals↗
PubMed1992

Immunological profiles of patients from endemic areas infected with Schistosoma mansoni.

Crude extracts of eggs (SEA) adult worms (SWAP) or cercariae (Cerc) have been used to stimulate Peripheral Blood Mononuclear cells (PBMC) and have provided rather distinct profiles of responses in different types of patients. In general it is clear that patients with early infections respond strongly to SEA while response to SWAP are develop more slowly. As infection progresses into the more chronic phases, a general pattern is seen which leads to lower anti-SEA proliferative responses in the face of higher responses to SWAP and variable anti-cerc responsiveness. Cured not re-exposed patients express very high levels of anti-SEA proliferation. It has recently been seen that those individuals who live in endemic areas and have continued water contact, but are repeatedly stool-negative (who are presumed to have self-cured or be putatively resistant; endemic normals) are strongly responsive to antigenic extracts, particularly to SEA. Furthermore, our results show that endemic normal individuals have significantly higher IFN gamma production upon PBMC stimulation with schistosome antigens than infected individuals. With the emergence of more studies it is becoming apparent that both the intensity and the prevalence of a given area may influence or shape the general responsiveness of the population under study.

Adolescent↗
PubMed1992

Human schistosomiasis mansoni: studies on in vitro granuloma modulation.

Infection with Schistosoma mansoni induces humoral and T cell mediated responses and leads to a delayed hypersensitivity that results in granulomatous inflammatory disease around the parasite eggs. Regulation of these responses resulting in a reduction in this anti-egg inflammatory disease is apparently determined by idiotypic repertoires of the patient, associated with genetic background and multiple external factors. We have previously reported on idiotype/anti-idiotype-receptor interactions in clinical human schistosomiasis. These findings support a hypothesis that anti-SEA cross-reactive idiotypes develop in some patients during the course of a chronic infection and participate in regulation of anti-SEA cellular immune responses. We report here on experiments which extend those observations to the regulation of granulomatous hypersensitivity measured by an in vitro granuloma model. T cells from chronic intestinal schistosomiasis patients were stimulated in vitro with anti-SEA idiotypes and assayed in an autologous in vitro granuloma assay for modulation of granuloma formation. These anti-SEA idiotype reactive T cells were capable of regulating autologous in vitro granuloma formation. Both CD4 and CD8 T cells could be activated to regulate granuloma formation. This regulatory activity, initiated with stimulatory anti-SEA idiotypic antibodies, was antigenically specific and was dependent on the presence of intact (F(ab')2) immunoglobulin molecules. The ability to elicit this regulatory activity appears to be dose dependent and is more easily demonstrated in chronically infected intestinal patients or SEA sensitized individuals.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Helminth↗
PubMed1992

Detection of Schistosoma mansoni circulating cathodic antigen for evaluation of resistance induced by irradiated cercariae.

The appearance of serum levels of circulating cathodic antigen (CCA) detectable by a monoclonal antibody (mAb) (5H11) antigen-capture sandwich enzyme-linked immunosorbent assay (ELISA) system was evaluated during acute Schistosoma mansoni infections in female CF1 mice exposed to either 100 or 25 cercariae. Measurable CCA levels occurred in these groups at 5 and 7 wk after infection, respectively. The kinetics of appearance of CCA were thus related to the intensity of infection. The level of resistance developed by female C57BL/6 mice upon immunization with irradiated cercariae, as expressed by both worm burden and CCA levels after cercarial challenge was evaluated. Immunization conferred 44% protection against the challenge infection, and the level of CCA detected in the sera of the control group was significantly (P less than 0.02) higher than that found in the sera of the immunized group, 6 wk after challenge. These results demonstrate that CCA detection by the 5H11 mAb antigen-capture sandwich ELISA can reflect vaccine-induced resistance against S. mansoni. Localization studies showed that 5H11 reacts with a CCA epitope in the adult worm gut and to a lesser extent with the male tegument. Adaptations of this and other antigen detection systems may prove useful in monitoring the efficacy of developmental vaccines, an ability that may be essential for the extension of such studies to humans.

Acute Disease↗
PubMed1991

Granulomatous hypersensitivity to Schistosoma mansoni egg antigens in human schistosomiasis. II. In vitro granuloma modulation induced by polyclonal idiotypic antibodies.

We have previously reported on Id/anti-Id-receptor interactions in clinical human schistosomiasis. These findings support a hypothesis that anti-SEA cross-reactive Id develop in some patients during the course of a chronic infection and participate in regulation of anti-SEA cellular immune responses. We report here on experiments that extend those observations to the regulation of granulomatous hypersensitivity measured by an in vitro granuloma model. T cells from chronic intestinal schistosomiasis patients were stimulated in vitro with anti-SEA Id and assayed in an autologous in vitro granuloma assay for modulation of granuloma formation. These anti-SEA Id-reactive T cells were capable of regulating autologous in vitro granuloma formation. Both CD4 and CD8 T cells could be activated to regulate granuloma formation. This regulatory activity, initiated with stimulatory anti-SEA idiotypic antibodies, was antigenically specific and was dependent on the presence of intact F(ab')2 Ig molecules. The ability to elicit this regulatory activity appears to be dose dependent and is more easily demonstrated in chronically infected intestinal patients or SEA-sensitized individuals. These data support the hypothesis that anti-SEA cross-reactive Id are important in regulating granulomatous hypersensitivity in chronic intestinal schistosomiasis patients and these cross-reactive Id appear to play a major role in cell-cell interactions that result in the regulation of anti-SEA cellular immune responses.

Animals↗
PubMed1991

In vivo molecular analysis of lymphokines involved in the murine immune response during Schistosoma mansoni infection. I. IL-4 mRNA, not IL-2 mRNA, is abundant in the granulomatous livers, mesenteric lymph nodes, and spleens of infected mice.

Using Northern Blot analysis, the endogenous levels of IL-4 and IL-2 mRNA in the spleens, mesenteric lymph nodes, and granulomatous livers of male CBA/J mice in the acute phase of infection with Schistosoma mansoni have been quantified. High levels of IL-4 mRNA were detected in all three tissues from infected mice, whereas none was detected in tissues from normal, uninfected, age-matched mice. Isolation of the granulomas from the livers of infected mice and subsequent extraction of total RNA from these lesions resulted in a 70-fold enrichment of IL-4 message compared with the whole, unseparated granulomatous liver tissue. Hence, the predominant source of the IL-4 mRNA detected in livers from infected mice appears to be the schistosome egg-induced granulomas within these livers. In contrast, IL-2 mRNA was never detected in any of these tissues from either infected or normal mice. Control experiments were performed that ruled out the possibility that this inability to detect IL-2 mRNA was due to a difference in the efficacy of the IL-4 and IL-2 probes or due to a selective lability of IL-2 message. These data imply that IL-4-producing, Th2 lymphocytes are active in and possibly integral to the granulomatous, delayed-type hypersensitivity response characteristic of this infection, and directly challenges the current hypothesis that delayed-type hypersensitivity responses are exclusively mediated by Th1 lymphocytes.

Animals↗