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T B Nutman

Publications and source records attributed to T B Nutman.

At least 19 recordsLinked to original sources
PubMed1992

Biochemical and immunologic characterization of a major IgE-inducing filarial antigen of Brugia malayi and implications for the pathogenesis of tropical pulmonary eosinophilia.

A major allergen of the human filarial parasite Brugia malayi has been identified by two-dimensional immunoblot analysis using a serum pool from patients with tropical pulmonary eosinophilia. The allergen is composed of two Ag with M(r) 23 and M(r) 25 and acidic isoelectric point (Bm23-25). Immunoblots using affinity-purified IgE antibodies to BM23-25 indicated that Bm23-25 is expressed mainly in the microfilarial stage. Digestion of the allergen with endoglycosidases indicates that it has N-linked oligosaccharide chains. Analysis of the reactivity of T cells derived from patients with lymphatic filariasis revealed that the Bm23-25 allergen was capable of stimulating T cell proliferation; Bm23-25 was also shown to induce IgE production in vitro from PBMC derived from patients with either TPE or other filarial symptoms. Bronchoalveolar lavage fluid of patients with TPE contained IgE antibodies that recognized Bm23-25 strongly, an observation suggesting that the microfilarial allergen might be involved in the pathogenesis of the TPE syndrome.

Allergens↗
PubMed1992

Parallel regulation of IL-4 and IL-5 in human helminth infections.

To investigate the relationship between cytokine production and the increased levels of serum IgE and peripheral eosinophilia commonly accompanying human helminth infections, we studied the ability of PBMC of normal (N1) (n = 18) and eosinophilic individuals with helminth infections (H1) (n = 9) to produce IL-3, IL-4, IL-5, granulocyte-macrophage-CSF, and IFN-gamma in vitro after stimulation with PMA (50 ng/ml) and ionomycin (1 microgram/ml). The two groups differed in both the levels of serum IgE and eosinophilia. For mitogen-induced production of granulocyte-macrophage-CSF and IFN-gamma, there was no difference in cytokine production between the two groups. In marked contrast, supernatants from PBMC of infected individuals had significantly higher levels of IL-4 (mean = 213 pg/ml for N1 and 944 pg/ml for H1, p less than 0.02), IL-5 (mean = 180 pg/ml for N1 and 1118 pg/ml for HL, p less than 0.001), and IL-3 (mean = 13900 pg/ml for N1, 28029 pg/ml for H1, p less than 0.05). In addition, helminth-infected patients had approximately 5-fold greater numbers of T cells capable of producing IL-5 and 2.5-fold greater frequency of IL-4-secreting cells than did normal individuals; GM-CSF- and IFN-gamma-producing T cell numbers were not significantly different in the two groups. IL-3-producing cell frequencies could not be evaluated by this method. There was a direct correlation between IL-4 production and IL-5 production at the level of both protein production and frequency of T cells capable of producing these cytokines. These data indicate that individuals with reactive eosinophilia and elevated serum IgE have an expanded population of lymphocytes producing IL-4 and IL-5 and the association of the two suggests that the regulation of IL-4 and IL-5 may be linked.

CD4-Positive T-Lymphocytes↗
PubMed1992

Characterization of a muscle-associated antigen from Wuchereria bancrofti.

A recombinant clone, WbN1, isolated from a genomic expression library of Wuchereria bancrofti and showing restricted specificity at the DNA level (Southern and PCR analyses) for Wuchereria bancrofti and Brugia malayi has been previously described. Sequence analysis of WbN1 indicated that it had notable similarity to myosin. Further characterization using in situ hybridization has localized the mRNA in the muscle of the adult parasite and in the microfilariae. Rabbit polyclonal antiserum, raised against the recombinant WbN1 fused to the maltose-binding protein, recognized a 200-kDa polypeptide in immunoblots containing B. malayi antigen extracts. The same antibody also recognized myosin extracted from Brugia pahangi, Onchocerca volvulus, and Caenorhabditis elegans. Localization using the rabbit antiserum revealed the presence of the antigen in the adult muscle tissue and in the microfilariae; the same antibody inhibited the binding of a monoclonal antibody 28.2 (directed toward MHC B of C. elegans myosin) to the recombinant WbN1 antigen and also to purified C. elegans myosin. Based on homology data, structural location, competitive ELISA, and immunoblot we conclude that WbN1 is related to myosin or a similar myofibrillar protein.

Amino Acid Sequence↗
PubMed1992

Tropical pulmonary eosinophilia.

Tropical pulmonary eosinophilia is one of the many PIE syndromes [pulmonary infiltrates with eosinophilia (of the peripheral blood)]. It is caused by immunologic hyperresponsiveness to the filarial parasites Wuchereria bancrofti or Brugia malayi. Its clinical presentation includes nocturnal cough, dyspnea, wheezing, fever, weight loss, fatigue, interstitial mottling on chest radiograph, predominantly restrictive but also obstructive lung function abnormalities, and peripheral blood eosinophilia of more than 3000 per microliter. It can be distinguished from other PIE syndromes by the patient's history of residence in the tropics, by the presence of extraordinarily high levels of both serum IgE and antifilarial antibodies, and by the dramatic clinical improvement after treatment with the antifilarial drug diethylcarbamazine. Recent studies indicate that the compromised lung diffusion capacity of patients with acute tropical pulmonary eosinophilia is a function of the degree of the eosinophilic alveolitis present and that, despite a 3-week course of diethylcarbamazine, low-grade alveolitis persists in almost half of such patients; this persistent alveolitis is likely to be the cause of the progressive interstitial fibrosis seen in many untreated or inadequately treated patients with tropical pulmonary eosinophilia.

Animals↗
PubMed1992

Pulmonary involvement in loiasis.

A 40-yr-old West African man presented acutely with pleural effusion. Cytologic evaluation of the pleural fluid revealed Loa loa microfilariae. No additional etiology for the pleural effusion could be identified, and antifilarial treatment with diethylcarbamazine led to a rapid resolution of the patient's symptoms and pulmonary abnormalities. Loa loa must be considered as a treatable cause of eosinophilic pleural effusions in persons from endemic areas of West and Central Africa.

Adult↗
PubMed1992

Immunologic tolerance in lymphatic filariasis. Diminished parasite-specific T and B lymphocyte precursor frequency in the microfilaremic state.

To explore the mechanisms of antigen-specific immune unresponsiveness seen in microfilaremic patients with bancroftian filariasis, T and B cell precursor frequency analysis was performed using PBMC from individuals with either asymptomatic microfilaremia (MF, n = 7) or chronic lymphatic obstruction (CP, n = 20). Highly purified CD3+ cells were partially reconstituted with adherent cells and their proliferative response to parasite antigens determined in cultures of T cells by limiting dilution analysis. A filter immunoplaque assay also assessed the frequency of both total and parasite-specific Ig-producing B cells. While the lymphocyte proliferation to mitogens and to a nonparasite antigen (Streptolysin-O, [SLO]) were similar in all groups of patients, the frequency of parasite-specific CD3+ T cells was significantly lower (geometric mean [GM], 1/3,757) in MF patients when compared to that in CP patients (GM 1/1,513; P less than 0.001). Similarly, the proportion of lymphocytes producing parasite-specific IgE or IgG was significantly lower in MF patients (IgE mean, 0.2%; IgG mean, 0.33%) compared with CP patients (IgE mean, 3.2%; IgG mean, 1.76%; P less than 0.05 for both comparisons). These observations imply that low numbers of parasite-specific T and B lymphocytes may be partially responsible for the severely diminished capacity of lymphocytes from patients with MF to produce parasite-specific antibody and to proliferate to parasite antigen in vitro. Such differences in parasite-specific lymphocyte responses suggest that tolerance by clonal anergy may be a critical mechanism for maintaining the microfilaremic state.

Animals↗
PubMed1991

Analysis of T cell stimulation by superantigen plus major histocompatibility complex class II molecules or by CD3 monoclonal antibody: costimulation by purified adhesion ligands VCAM-1, ICAM-1, but not ELAM-1.

Many ligands of adhesion molecules mediate costimulation of T cell activation. The generality of this emerging concept is best determined by using model systems which exploit physiologically relevant ligands. We developed such an "antigen-specific" model system for stimulation of resting CD4+ human T cells using the following purified ligands: (a) major histocompatibility complex class II plus the superantigen Staphylococcus enterotoxin A, to engage the T cell receptor (TCR); (b) adhesion proteins vascular cell adhesion molecule 1 (VCAM-1), intercellular adhesion molecule 1 (ICAM-1), and endothelial leukocyte adhesion molecule 1 (ELAM-1), to provide potential cell surface costimulatory signals; and (c) recombinant interleukin 1 beta (rIL-1 beta)/rIL-6 as costimulatory cytokines. In this biochemically defined system, we find that resting CD4+ T cells require costimulation in order to respond to TCR engagement. This costimulation can be provided by VCAM-1 or ICAM-1; however adhesion alone is not sufficient since ELAM-1 mediates adhesion but not costimulation. The cytokines IL-1 beta and IL-6 by themselves cannot mediate costimulation, but augment the adhesion ligand-mediated costimulation. Direct comparison with the model of TCR/CD3 engagement by CD3 monoclonal antibody demonstrated comparable costimulatory requirements in both systems, thereby authenticating the commonly used CD3 model. The costimulation mediated by the activation-dependent interaction of the VLA-4 and LFA-1 integrins with their respective ligands VCAM-1 and ICAM-1 leads to increased IL-2R alpha (CD25) expression and proliferation in both CD45RA+ CD4+ and CD45RO+ CD4+ T cells. The integrins also regulate the secretion of IL-2, IL-4, and granulocyte/macrophage colony-stimulating factor. In contrast the activation-independent adhesion of CD4+ T cell to ELAM-1 molecules does not lead to T cell stimulation as measured by proliferation, IL-2R alpha expression, or cytokine release. These findings imply that adhesion per se is not sufficient for costimulation, but rather that the costimulation conferred by the VLA-4/VCAM-1 and LFA-1/ICAM-1 interactions reflects specialized accessory functions of these integrin pathways. The new finding that VLA-4/VCAM-1 mediates costimulation adds significance to observations that VCAM-1 is expressed on a unique set of potential antigen-presenting cells in vivo.

Antibodies, Monoclonal↗
PubMed1991

An immunogenic Onchocerca volvulus antigen: a specific and early marker of infection.

Onchocerciasis (river blindness) is a serious health problem and a severe obstacle to social and economic development, especially in Africa. A complementary DNA fragment coding for an Onchocerca volvulus antigen (OV-16) was cloned and expressed in the plasmid vector pCG808fx. Immune responses to this O. volvulus-specific recombinant antigen were detectable in patients with documented onchocerciasis; the antibody response was also detectable at 3 months and at more than 1 year before infection could otherwise be detected in humans and in chimpanzees experimentally infected with O. volvulus third-stage larvae.

Animals↗
PubMed1991

Frequency analysis of IgE-secreting B lymphocytes in persons with normal or elevated serum IgE levels.

The immunoregulatory mechanisms that determine the high serum IgE antibody levels in disorders such as helminth parasite infections and the hyper-IgE recurrent infection syndrome (HIE) remain poorly understood. To assess whether elevated serum IgE levels result from an increased number of B lymphocytes committed to IgE production, the proportion of IgE-producing B lymphocytes was determined by a filter immunoplaque assay using PBMC from persons with a broad range of serum IgE levels that included normal persons (n = 9) and patients with loiasis (n = 12), tropical pulmonary eosinophilia (TPE) (n = 6), lymphatic filariasis (n = 28), and HIE (n = 8). PBMC from these persons were assessed for production of in vitro IgE. The geometric mean number of IgE-secreting cells in 10(5) B lymphocytes in PBMC was 0.42 (range 0-2.2) in normal persons, 5.6 (range 0.1-35.5) among patients with loiasis, 9.4 (range 0-53.2) among patients with lymphatic filariasis, 52 (range 31.5-115) among patients with TPE, and 218 (range 56-1404) among patients with HIE. When all study subjects were grouped, there were significant correlations with serum IgE levels (r2 = 0.78; p less than 0.0001) and net spontaneous in vitro IgE production (r2 = 0.8; p less than 0.0001). Estimates of the amount of IgE production per B lymphocyte were similar among normal persons, patients with filarial infections, and patients with TPE (geometric means of 134, 96, and 141 pg/ml/cell, respectively); in contrast, for HIE patients, IgE production by individual B cells was significantly lower (geometric mean 28 pg/ml/cell; p less than 0.001). These observations demonstrate that clonal expansion of IgE-producing B lymphocytes is a major mechanism underlying the elevated serum IgE levels seen in persons with hyper-IgE states.

Adolescent↗
PubMed1991

Cloning and characterization of a species-specific repetitive DNA sequence from Loa loa.

A genomic DNA library of Loa loa was constructed in lambda gt11 using EcoRI-digested DNA from microfilariae isolated from two West African patients. Screening with labeled L. loa DNA yielded several potential repetitive DNA clones. An MboI fragment of one of these, LL3M9, was identified and characterized. Sequence analysis of LL3M9 revealed an 839-bp fragment with an unusual 356-bp region containing 37 copies of the hexamer CTTAGG, many of which are arranged in repeated motifs of 12, 27 and 63 bp. This region shares many of the characteristics of eukaryotic satellite DNA. A synthetic oligonucleotide corresponding to the 27-bp repeated motif, LL3M9REP, was found to be both sensitive and species-specific by dot hybridization. Species specificity of LL3M9REP was confirmed by amplification of the repetitive region using genomic DNA as a template in the polymerase chain reaction.

Animals↗
PubMed1991

A recombinant clone of Wuchereria bancrofti with DNA specificity for human lymphatic filarial parasites.

In order to understand the immune response to Wuchereria bancrofti and to aid in the diagnosis of W. bancrofti infections, recombinant antigens were identified from a W. bancrofti genomic expression library made in lambda gt11 using a pool of sera from infected Indian patients. One of the recombinant clones, lambda WbN1, containing a 2.5-kb insert, reacted strongly to a pool of sera from patients with lymphatic filariasis but not to normal human sera. In addition, this clone showed restricted specificity at the genomic level to the major lymphatic filarial parasites W. bancrofti and Brugia malayi but not to the closely related filarial parasite Brugia pahangi or to other filarial and non-filarial species tested. Nucleotide sequence analysis indicated the cloned DNA to have homology to myosin-like myofibrillar proteins. Polymerase chain reaction amplification initiated by specific synthetic oligomers amplified DNA in a species-specific manner from as little as 16 pg of isolated DNA or from one microfilaria.

Amino Acid Sequence↗
PubMed1991

Regulation of the immune response in lymphatic filariasis and onchocerciasis.

The persistence of microfilariae in the blood or skin accompanied by a prominent eosinophilia and elevated serum IgE levels are common features of human infection with filarial parasites. In this review Christopher King and Thomas Nutman discuss recent findings on the role of interleukin 4 (IL-4), IL-5 and gamma-interferon (IFN-gamma) in the induction of these immediate hypersensitivity responses. They discuss the role of hypersensitivity in immunity, the development of immune tolerance to filarial antigens and suggest that could explain the impaired immune response of some individuals to filarial infections and the persistence of the microfilaremic state.

Animals↗
PubMed1991

Immunity to onchocerciasis: recognition of larval antigens by humans putatively immune to Onchocerca volvulus infection.

Immunoblot analyses were done using sera from 12 individuals without evidence of onchocerciasis and 16 with active infection from an area of Guatemala holoendemic for onchocerciasis. For adult antigens from Onchocerca volvulus, no differences in antigen recognition could be identified between the two groups. In contrast, when infective larval (L3) antigen preparations derived from the related animal parasite Onchocerca lienalis were used, IgG from the "immune" individuals preferentially recognized a 45- to 50-kDa triplet and a 22-kDa L3 antigen. When L3 antigens of Brugia malayi were used, sera from putatively immune individuals identified a high-molecular-weight triplet/quadruplet plus several additional antigens of lower molecular weights that were recognized by sera from few (or none) of the infected patients. These findings define some differences in antibody specificity in onchocerciasis patients and therefore might define potential target antigens of humoral host defense. The exact nature of such defenses is unknown.

Adolescent↗
PubMed1991

Loiasis in endemic and nonendemic populations: immunologically mediated differences in clinical presentation.

To define the clinical spectrum of loiasis more precisely and to begin to assess the immunologic basis for the difference in clinical manifestations between visitors to endemic areas and natives of these areas, 51 West African patients with loiasis were evaluated and compared with 42 infected expatriates. Microfilaremia was present in 90% and Calabar swellings in only 16% of the endemic patients. Conversely, only 10% of the expatriates were microfilaremic while 95% complained of Calabar swellings. The endemic population showed significantly decreased levels of peripheral blood eosinophils, parasite-specific IgG, and lymphocyte proliferation to parasite antigens compared with the nonendemic population. These findings support the hypothesis that differences in the modulation of the immune response to parasite antigen are responsible for the observed differences in clinical presentation between expatriate and endemic populations with loiasis.

Adolescent↗
PubMed1991

Immunologic responses to repeated ivermectin treatment in patients with onchocerciasis.

To assess the effect of ivermectin treatment on the immunologic status of individuals with onchocerciasis, 27 patients from Guatemala were studied before and at 6-month intervals during 2 years of repeated semiannual treatment with ivermectin. T cell proliferative responses to onchocercal antigen increased transiently by 6 months (mean stimulation index [SI] rising from 4.17 to 12.81) but returned to preivermectin levels thereafter. Changes in SI to nonparasite antigen paralleled those induced by parasite antigen. There were also significant decreases in levels of blood eosinophils, polyclonal IgG and IgE, parasite-specific IgG antibody, and IgG subclass antibodies by the end of the study. This study emphasizes the apparent long-term safety of ivermectin by demonstrating the absence of immunopathogenic responses induced by repeated ivermectin treatments.

Adolescent↗
PubMed1991

Immunoregulation in onchocerciasis. Functional and phenotypic abnormalities of lymphocyte subsets and changes with therapy.

To help define the immunoregulatory defects in patients with onchocerciasis, flow cytometric analysis of circulating lymphocyte subpopulations was performed in parallel with functional assays. No significant differences in CD4/CD8 ratios were seen when microfilariae-positive individuals from Guatemala were compared with Guatemalan controls. However, the infected individuals had significantly increased numbers of circulating CD4+CD45RA+ lymphocytes (mean 38.3%) when compared with controls (mean 16.0%). Coexpression of the activation marker HLA-DR was significantly increased on CD4+ cells from infected individuals. In contrast, no up-regulation of HLA-DR was seen on CD8+ or CD19+ cells. At 1 year after initiation of treatment with semiannual doses of the microfilaricide ivermectin, there were significant increases (P less than 0.05) in the percentage of CD4+CD45RA- cells, the percentage of CD4+HLA-DR+ cells, and mitogen-induced lymphokine production (IL-2, IL-4). Despite these changes, parasite-specific IL-2 and IL-4 production which had been undetectable before treatment did not manifest itself even by the 2-yr follow-up. Defects in the T-cell activation pathway in Onchocerca volvulus-infected individuals may thus exist at several independent points; a state of parasite antigen-specific tolerance appears to remain even after the relative reversal of other generalized immunoregulatory defects.

Adolescent↗
PubMed1991

Interleukin-5 and the posttreatment eosinophilia in patients with onchocerciasis.

To understand the role of the eosinophilopoietic cytokine IL-5 in humans, the posttreatment eosinophilic response in a group of microfilaria (mf)-positive patients with onchocerciasis (n = 10) was examined before and after treatment with diethylcarbamazine (6 mg/kg for 7 d). Sequential blood samples were assessed at 24 and 1 h before treatment (baseline values), then at frequent intervals over the next 14 d. Symptom scores, skin microfilariae (mf), and peripheral blood eosinophil counts were recorded as a function of time after treatment, and serum levels of IL-5 were quantitated by a highly sensitive (sensitivity greater than or equal to 20 pg/ml) monoclonal-based ELISA. Pretreatment eosinophil counts ranged from 240 to 1,186 eosinophils/microliter (geometric mean, 675), and the mf counts from 10 to 218 per mg skin (geometric mean, 79). After an initial decline in the peripheral eosinophil count to 28 +/- 8% of pretreatment levels at 8 h after beginning treatment, the eosinophil counts steadily increased over the next 2 wk, reaching a maximum at 14 d (257 +/- 38% of pretreatment levels). Serum levels of IL-5 rose sharply from pretreatment levels to a peak of 70.5 +/- 11 pg/ml by 24 h after treatment. Serum IL-5 remained elevated over the next 2-3 d and declined toward baseline by approximately 6 d after treatment, at which time the eosinophil levels were steadily increasing. IL-3 and granulocyte macrophage colony-stimulating factor, two other cytokines implicated in eosinophilopoeisis, were not detectable in the serum at any time before or after treatment. The rise in serum IL-5 before the posttreatment eosinophilia seen in this group of patients with onchocerciasis demonstrates a temporal relationship between IL-5 and the subsequent development of eosinophilia and implicates IL-5 as an important mediator of eosinophilia in humans.

Adolescent↗