RESUMEN

Specific polysaccharide antibody deficiency (SPAD) is a well reported immunodeficiency characterized by a failure to produce antibodies against polyvalent polysaccharide antigens, expressed by encapsulated microorganisms. The clinical presentation of these patients involves recurrent bacterial infections, being the most frequent agent Streptococcus (S.) pneumoniae. In SPAD patients few reports refer to cells other than B cells. Since the immune response to S. pneumoniae and other encapsulated bacteria was historically considered restricted to B cells, the antibody deficiency seemed enough to justify the repetitive infections in SPAD patients. Our purpose is to determine if the B cell defects reported in SPAD patients are accompanied by defects in other leukocyte subpopulations necessary for the development of a proper adaptive immune response against S. pneumoniae. We here report that age related changes observed in healthy children involving increased percentages of classical monocytes (CD14++ CD16- cells) and decreased intermediate monocytes (CD14++ CD16+ cells), are absent in SPAD patients. Alterations can also be observed in T cells, supporting that the immune deficiency in SPAD patients is more complex than what has been described up to now.

Asunto(s)

Linfocitos B/inmunología , Síndromes de Inmunodeficiencia/inmunología , Monocitos/inmunología , Infecciones Neumocócicas/inmunología , Streptococcus pneumoniae/inmunología , Subgrupos de Linfocitos T/inmunología , Linfocitos T/inmunología , Inmunidad Adaptativa/genética , Adolescente , Adulto , Anticuerpos/sangre , Linfocitos B/microbiología , Diferenciación Celular , Niño , Femenino , Humanos , Síndromes de Inmunodeficiencia/genética , Masculino , Infecciones Neumocócicas/genética , Polisacáridos/inmunología , Adulto Joven

RESUMEN

In Argentina, more than 3 million people suffer from asthma, with numbers rising. When asthma patients acquire viral infections which, in turn, trigger the asthmatic response, they may develop subsequent bacterial infections, mainly by Streptococcus (S.) pneumoniae. This encapsulated Gram(+) bacterium has been considered historically a T cell-independent antigen. Nevertheless, several papers describe the role of T cells in the immune response to S. pneumoniae. We evaluated the response to S. pneumoniae and compared it to the response to Mycobacterium (M.) tuberculosis, a different type of bacterium that requires a T helper type 1 (Th1) response, in cells from atopic asthmatic children, to compare parameters for the same individual under exacerbation and in a stable situation whenever possible. We studied asthma patients and a control group of age-matched children, evaluating cell populations, activation markers and cytokine production by flow cytometry, and cytokine concentration in serum and cell culture supernatants by enzyme-linked immunosorbent assay (ELISA). No differences were observed in γδ T cells for the same patient in either situation, and a tendency to lower percentages of CD4(+) CD25(hi) T cells was observed under stability. A significantly lower production of tumour necrosis factor (TNF)-α and a significantly higher production of interleukin (IL)-5 was observed in asthma patients compared to healthy individuals, but no differences could be observed for IL-4, IL-13 or IL-10. A greater early activation response against M. tuberculosis, compared to S. pneumoniae, was observed in the asthmatic patients' cells. This may contribute to explaining why these patients frequently acquire infections caused by the latter bacterium and not the former.

Asunto(s)

Asma/inmunología , Streptococcus pneumoniae/inmunología , Subgrupos de Linfocitos T/inmunología , Células Th2/inmunología , Adolescente , Androstadienos/uso terapéutico , Antiasmáticos/uso terapéutico , Antígenos Bacterianos/inmunología , Asma/tratamiento farmacológico , Vacuna BCG , Células Cultivadas/efectos de los fármacos , Células Cultivadas/inmunología , Células Cultivadas/metabolismo , Niño , Citocinas/sangre , Femenino , Fluticasona , Humanos , Inmunofenotipificación , Interferón gamma/sangre , Leucocitos Mononucleares/inmunología , Activación de Linfocitos , Masculino , Mycobacterium tuberculosis/inmunología , Adulto Joven

RESUMEN

Atopic asthma results from airway inflammation triggered by an environmental allergen. Symptoms include wheezing, dyspnea and cough, airway narrowing and/or hyperresponsiveness to several inhaled stimuli. Inflammation develops in a two-phase fashion. The first phase after exposure to the allergen consists of degranulation and release of both histamine and other stored preformed inflammatory mediators as well as newly synthesized ones, including cytokines, all of which increase mucus secretion and smooth muscle contraction. The second phase occurs later and lasts longer; it is due to different molecules: several cytokines and chemokines, arachidonic acid derivatives, enzymes such as metalloproteinases and cell adhesion molecules. Cytokines are key players in the chronic inflammation in asthma patients, but details on their role and interactions still remain undetermined. Recent evidence suggests that allergic asthma is a multifaceted condition actively controlled by effector as well as regulatory T cells (Tregs). T helper (Th) 2 cells and Th17 cells increase airway inflammation, while Tregs are anti- inflammatory. Cytokines are involved in the development and activation of all T cell subpopulations. They are also involved directly or indirectly in most approaches to asthma treatment. Several cytokines have been tested as therapeutic targets and some of the currently used therapies like corticosteroids, beta agonists and allergen immunotherapy affect cytokine production. The increased knowledge on cytokine interplay and lymphocyte subsets should generate new therapeutic strategies in the near future.

Asunto(s)

Asma/inmunología , Citocinas/inmunología , Receptores de Citocinas/inmunología , Animales , Asma/terapia , Eosinófilos/inmunología , Células Epiteliales/inmunología , Humanos , Mastocitos/inmunología , Receptores de Citocinas/metabolismo , Linfocitos T/inmunología , Células Th2/inmunología

RESUMEN

Interleukin 9 (IL-9) is a T-cell derived factor preferentially expressed by CD4+ Th2 cells and it has been characterized both in human and murine systems. It is a pleiotropic cytokine with multiple functions on cells of the lymphoid, myeloid and mast cell lineages, as well as on lung epithelial cells. Other activities described for IL-9 support its contribution to asthma and its important role in helminthic infections, where a Th2 response can be protective and IL-9 enhances resistance or is responsible for elimination of the nematode. Nevertheless, until recently there were no studies on its role in bacterial infections in man. We have demonstrated that cytokines can modulate the specific cytotoxicity generation in peripheral blood mononuclear cells from leprosy patients and normal controls. In the present report we studied the effect of IL-9 in this experimental model. Our results indicate that IL-9 can counteract the negative effect mediated by IL-4 on the generation of M. leprae-induced cytotoxic T lymphocytes. Moreover, it can increase this lytic activity in controls and enhance the stimulatory effect of IL-2 or IL-6 in cells from leprosy patients and controls. IL-9 is also able to revert the inhibitory effect of IL-10 and IL-13 on the M. leprae-induced cytotoxic activity. Although the exact mechanism of action of IL-9 remains to be determined, interferon gamma seems to be required for the effect of IL-9 in this experimental model. These data suggest that IL-9 may have an atypical Th2 behaviour and play a role in the modulation of the immune response to mycobacterial infections.

Asunto(s)

Interferón gamma/inmunología , Interleucina-9/farmacología , Lepra/inmunología , Mycobacterium leprae , Linfocitos T/inmunología , Adolescente , Adulto , Anciano , Estudios de Casos y Controles , Células Cultivadas , Citotoxicidad Inmunológica , Femenino , Humanos , Inmunización , Interferón gamma/genética , Interleucina-10/inmunología , Interleucina-13/inmunología , Interleucina-2/inmunología , Interleucina-4/inmunología , Interleucina-6/inmunología , Macrófagos/inmunología , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Estadísticas no Paramétricas

RESUMEN

Protection against intracellular pathogens such as Mycobacterium leprae is critically dependent on the function of NK cells at early stages of the immune response and on Th1 cells at later stages. In the present report we evaluated the role of IL-18 and IL-13, two cytokines that can influence NK cell activity, in the generation of M. leprae-derived hsp65-cytotoxic T lymphocytes (CTL) from peripheral blood mononuclear cells (PBMC) of leprosy patients. We demonstrated that IL-18 modulates hsp65-induced CTL generation and collaborates with IL-12 for this effect. In paucibacillary (PB) patients and normal controls (N) depletion of NK cells reduces the cytolytic activity. Under these conditions, IL-12 cannot up-regulate this CTL generation, while, in contrast, IL-18 increases the cytotoxic activity both in the presence or absence of NK cells. IL-13 down-regulates the hsp65-induced CTL generation and counteracts the positive effect of IL-18. The negative effect of IL-13 is observed in the early stages of the response, suggesting that this cytokine affects IFNgamma production by NK cells. mRNA coding for IFNgamma is induced by IL-18 and reduced in the presence of IL-13, when PBMC from N or PB patients are stimulated with hsp65. Neutralization of IL-13 in PBMC from multibacillary (MB) leprosy patients induces the production of IFNgamma protein by lymphocytes. A modulatory role on the generation of hsp65 induced CTL is demonstrated for IL-18 and IL-13 and this effect takes place through the production of IFNgamma.

Asunto(s)

Proteínas Bacterianas/inmunología , Chaperoninas/inmunología , Interleucina-13/inmunología , Interleucina-18/inmunología , Células Asesinas Naturales/inmunología , Lepra/inmunología , Adulto , Anciano , Antígeno CD56/análisis , Chaperonina 60 , Citotoxicidad Inmunológica/inmunología , Humanos , Interferón gamma/biosíntesis , Interferón gamma/genética , Interferón gamma/inmunología , Interleucina-12/inmunología , Persona de Mediana Edad , Mycobacterium leprae/inmunología , ARN Mensajero/genética , Linfocitos T Citotóxicos/inmunología

RESUMEN

The ability of peripheral blood mononuclear cells (PBMC) from patients with active tuberculosis to display cytotoxic responses against autologous Mycobacterium tuberculosis (Mtb)-pulsed macrophages was evaluated. Non-MHC restricted cell-dependent lytic activity was observed in ex vivo effector cells from tuberculosis patients and was mediated mainly by CD3(+)gammadelta TCR(+) T (gammadelta T) cells bearing CD56 and/or CD16 molecules. MHC-restricted and non-MHC restricted cytotoxic T cells (CTL) were differentially expanded upon stimulation with Mtb in tuberculosis patients and normal controls (N). Class-I restricted CD8(+) CTL and class-II restricted CD4(+) CTL were generated in PPD(+)N and to a lesser extent in PPD(-)N. Mtb-stimulated effector cells from tuberculosis patients became progressively non-MHC restricted CD4(-)CD8(-)gammadelta T cells, while lytic activity of CD4(+) and CD8(+)CTL decreased gradually as the disease became more severe. On the other hand, target cells were lysed by ex vivo cells from tuberculosis patients through the Fas-FasL and perforin pathways. Mtb-induced CD4(+) CTL from tuberculosis patients and N controls preferentially employed the Fas-FasL mechanism. Mtb-induced CD8(+) CTL effector cells from patients used the perforin-based mechanism while cells from N controls also used the Fas-FasL pathway. While Mtb-induced gammadelta CTL from patients and PPD(-)N employed the latter mechanism cells from PPD(+)N individuals also used the perforin pathway. It can be concluded that shifts in the CTL response and the cytolytic mechanisms take place as the pulmonary involvement becomes more severe.

Asunto(s)

Antígenos Bacterianos/inmunología , Citotoxicidad Inmunológica , Mycobacterium tuberculosis/inmunología , Tuberculosis Pulmonar/inmunología , Adulto , Anciano , Complejo CD3/análisis , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Células Cultivadas , Femenino , Humanos , Receptores de Lipopolisacáridos/análisis , Activación de Linfocitos/inmunología , Macrófagos/inmunología , Complejo Mayor de Histocompatibilidad , Masculino , Persona de Mediana Edad , Receptores de Antígenos de Linfocitos T gamma-delta/análisis , Linfocitos T Citotóxicos/inmunología , Tuberculina/inmunología

RESUMEN

Peripheral blood mononuclear cells from leprosy patients and normal individuals were analysed for their ability to lyse autologous macrophages pulsed with the Mycobacterium leprae 10 kDa heat shock protein (hsp10), an antigen considered to have an important role in the protective responses in leprosy. Strong cytotoxic responses, with an involvement of gammadelta T and class-I and class-II restricted alphabeta T cells and/or CD16+56+ cells, were observed in normal individuals, paucibacillary (PB) and those multibacillary (MB) patients with undetectable bacillary load. On the contrary, only a weak class-II restricted cytotoxic response was observed in those MB patients with positive bacillary load (MB(+)). Simultaneous addition of IFNgamma plus TNFalpha and IL-12 during hsp10 stimulation could partially upregulate the low cytotoxic response observed in MB(+) by enhancing class-II restricted T cell activity and by development of gammadelta T and/or CD16+56+ cell activity. Our results suggest that the ability to mount an effective cytotoxic response against hsp10-pulsed macrophages in leprosy patients is closely related to the patient's bacterial load and not to the clinical form of the disease.

Asunto(s)

Chaperonina 10/inmunología , Pruebas Inmunológicas de Citotoxicidad , Lepra/inmunología , Lepra/microbiología , Macrófagos/inmunología , Mycobacterium leprae/crecimiento & desarrollo , Mycobacterium leprae/inmunología , Adulto , Anciano , Antígeno CD56/biosíntesis , Diferenciación Celular/inmunología , Células Cultivadas , Chaperonina 10/metabolismo , Femenino , Humanos , Interferón gamma/fisiología , Interleucina-12/fisiología , Células Asesinas Naturales/inmunología , Leucocitos Mononucleares/inmunología , Activación de Linfocitos , Masculino , Persona de Mediana Edad , Receptores de Antígenos de Linfocitos T alfa-beta/biosíntesis , Receptores de Antígenos de Linfocitos T gamma-delta/biosíntesis , Receptores de IgG/biosíntesis , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/microbiología , Linfocitos T Citotóxicos/citología , Linfocitos T Citotóxicos/inmunología , Linfocitos T Citotóxicos/microbiología , Factor de Necrosis Tumoral alfa/fisiología

RESUMEN

Interleukin-12 (IL-12) is a major immunomodulatory cytokine that represents a functional bridge between the early resistance and the subsequent antigen specific adaptive immunity. TNF-alpha and IFN-gamma have an important role in the generation of hsp65 specific cytotoxic T lymphocytes (CTL) that lyse hsp65-pulsed autologous macrophages (hsp65 CTL). Since a positive feedback mechanism between TNF-alpha, IFN-gamma and IL-12 has been described, we undertook to evaluate the role of IL-12 on the hsp65 CTL generation in leprosy patients. Our results show that the presence of IL-12 during the first 24 h of the in vitro antigen stimulation amplifies the hsp65 cytotoxic response whenever both IFN-gamma and TNF-alpha are present. The addition of these three cytokines (CKs) was able to abrogate the inhibitory effect of IL-10 on hsp65 CTL in cells from paucibacillary patients (PB) but not that of IL-4 in PB and normal controls (N). Both IL-12 or anti IL-4 enhanced the cytotoxic activity in cells from multibacillary patients (MB). Anti IL-4 upregulated the binding of IFN-gamma and did not modify that of TNF-alpha so the low CTL activity could be as a result of IL-4 by a decrease of the IFN-gamma binding on MB cells. Cells from those MB patients taking thalidomide (MB-T) did neither bind IFN-gamma nor TNF-alpha even when antigen or anti-IL-4 were added, demonstrating that thalidomide inhibits either the in vitro binding or receptor expression of both TNF-alpha and IFN-gamma. Development of CD56 effector cells during the hsp65 stimulation was observed in PB and N by the addition of IL-12 plus TNF-alpha and IFN-gamma, while in MB and MB-T anti IL-4 was also required. So, the inhibitory effect of IL-4 on either production of IFN-gamma, TNF-alpha and/or IL-12 or their receptors could be the mechanism underlying the lack of the hsp65 CTL generation in cells from MB.

Asunto(s)

Proteínas Bacterianas , Chaperoninas/inmunología , Citotoxicidad Inmunológica/inmunología , Interferón gamma/biosíntesis , Interleucina-12/fisiología , Interleucina-4/fisiología , Mycobacterium leprae/inmunología , Linfocitos T Citotóxicos/inmunología , Factor de Necrosis Tumoral alfa/biosíntesis , Adulto , Anciano , Antígeno CD56/biosíntesis , Células Cultivadas , Chaperonina 60 , Regulación hacia Abajo/inmunología , Sinergismo Farmacológico , Femenino , Humanos , Sueros Inmunes/farmacología , Interferón gamma/antagonistas & inhibidores , Interferón gamma/metabolismo , Interferón gamma/fisiología , Interleucina-10/fisiología , Interleucina-12/inmunología , Interleucina-12/metabolismo , Interfase/inmunología , Lepra/inmunología , Leucocitos Mononucleares/inmunología , Leucocitos Mononucleares/metabolismo , Activación de Linfocitos/inmunología , Complejo Mayor de Histocompatibilidad/inmunología , Masculino , Persona de Mediana Edad , Unión Proteica/inmunología , Linfocitos T Citotóxicos/metabolismo , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Factor de Necrosis Tumoral alfa/metabolismo , Factor de Necrosis Tumoral alfa/fisiología

Asunto(s)

/biosíntesis , Activación de Linfocitos/inmunología , Chaperoninas/inmunología , Citotoxicidad Inmunológica/inmunología , Complejo Mayor de Histocompatibilidad/inmunología , Factor de Necrosis Tumoral alfa/biosíntesis , Factor de Necrosis Tumoral alfa/fisiología , Factor de Necrosis Tumoral alfa/metabolismo , Lepra/inmunología , Interfase/inmunología , Interferón gamma/antagonistas & inhibidores , /fisiología , /fisiología , /inmunología , /metabolismo , /fisiología , Leucocitos Mononucleares/inmunología , Leucocitos Mononucleares/metabolismo , Unión Proteica/inmunología , Linfocitos T Citotóxicos/inmunología , Linfocitos T Citotóxicos/metabolismo , Mycobacterium leprae/inmunología , Sinergismo Farmacológico , Sueros Inmunes/farmacología

RESUMEN

Cytotoxic T cells (CTL) may play an important role in host defence against mycobacterial infections. CD4 CTL are preferentially induced by mycobacteria, but both CD4 and CD8 CTL may be necessary components of a protective immune response. The 65-kD mycobacterium heat shock protein (hsp65) is a poor inducer of CTL in multibacillary leprosy (MB) patients. In this study we evaluate the possible role of cytokines in modulating the cytotoxic activity of CTL from leprosy patients and normal individuals (N) against autologous macrophages presenting Mycobacterium leprae hsp65. Our results show that hsp65-specific CTL were generated from both CD4 and CD8 lymphocytes. In N, individual cytokines as well as the combination of them were able to modify the hsp65-induced cytotoxic activity. The effect of cytokines on leprosy patients' lymphocytes was different in MB and paucibacillary (PB) patients. Thus, IL-6, IL-2, IFN-gamma or TNF-alpha did not modify the generation of hsp65-CTL from either MB (with or without an erythema nodosum episode (ENL)) or PB. In all the patients the simultaneous addition of two cytokines was required in order to increase CTL generation. In MB, IL-6 plus IFN-gamma or IL-2 increased both CD4 and CD8 CTL, while TNF-alpha plus IFN-gamma up-regulated only CD4 CTL. In PB, CD8 CTL were prominent with IL-6 plus IFN-gamma, while the increase was significant in CD4 CTL with IL-6 plus IL-2. Down-regulation of CTL was observed by addition of IL-4, IL-10, anti-IFN-gamma or anti-TNF-alpha in N controls. Our data demonstrate that IFN-gamma and TNF-alpha must be present for at least the first 60 h of the induction stage in order to generate full hsp65 CTL. Hence, IFN-gamma and TNF-alpha would be key factors in the generation of hsp65 CTL.

Asunto(s)

Proteínas Bacterianas , Linfocitos T CD4-Positivos/inmunología , Chaperoninas/inmunología , Interferón gamma/inmunología , Mycobacterium leprae/inmunología , Linfocitos T Citotóxicos/inmunología , Factor de Necrosis Tumoral alfa/inmunología , Adolescente , Adulto , Anciano , Antígenos Bacterianos/inmunología , Chaperonina 60 , Citotoxicidad Inmunológica , Regulación hacia Abajo , Femenino , Humanos , Interleucina-10/inmunología , Interleucina-2/inmunología , Interleucina-4/inmunología , Interleucina-6/inmunología , Células Asesinas Naturales/inmunología , Activación de Linfocitos , Masculino , Persona de Mediana Edad

RESUMEN

The aim of the present study was to evaluate the cytokine production by peripheral blood mononuclear cells (PBMC) of leprosy patients when the cells were stimulated in culture by ConA, PPD or M.leprae. We measured IL-2, IL-4, IFN-gamma and IL-6 in cell-free supernatants by enzyme linked immunoassays. Our results do not suggest a clear association of a clinical form of leprosy with either Th1 or Th2 cytokine secretion profile in PBMC of leprosy patients.

Asunto(s)

Citocinas/biosíntesis , Lepra/metabolismo , Adolescente , Adulto , Anciano , Células Sanguíneas/metabolismo , Femenino , Humanos , Lepra/inmunología , Macrófagos/metabolismo , Masculino , Persona de Mediana Edad , Mycobacterium leprae

RESUMEN

Cytotoxic T cells play an important role in host defence mechanisms, as well as in the immunopathology of leprosy. In this study, we evaluated whether Mycobacterium leprae hsp18, hsp65 and Myco. tuberculosis hsp71 could induce cytotoxic T cell activity against autologous macrophages pulsed with these hsp. Paucibacillary (PB) patients and normal controls generated more effector cells than multibacillary (MB) patients with all three hsp tested. There was no cross-reactivity between any of the hsp tested. Mycobacterium leprae hsp65 induced cytotoxic responses only in those MB patients undergoing an erythema nodosum leprosum (ENL) episode. Although hsp65 and hsp18 induced similar proliferation in MB patients, a high proportion of these patients did not generate cytotoxic effector cells in response to hsp65. Hence, those T cells reacting to hsp65 may play an important role in the control of Myco. leprae infection.

Asunto(s)

Citotoxicidad Inmunológica , Proteínas de Choque Térmico/inmunología , Leucocitos Mononucleares/inmunología , Macrófagos/inmunología , Mycobacterium leprae/inmunología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Células Cultivadas , Niño , Femenino , Humanos , Leucocitos Mononucleares/citología , Activación de Linfocitos , Masculino , Persona de Mediana Edad , Mycobacterium tuberculosis/inmunología , Linfocitos T Citotóxicos/inmunología

Asunto(s)

Activación de Linfocitos , Leucocitos Mononucleares/citología , Leucocitos Mononucleares/inmunología , Linfocitos T Citotóxicos/inmunología , Macrófagos/inmunología , Mycobacterium leprae/inmunología , Mycobacterium tuberculosis/inmunología , Proteínas de Choque Térmico/inmunología

RESUMEN

In this study we have investigated the effect of human mononuclear leukocytes (ML) on platelet aggregation. The results obtained demonstrated that coincubation of platelets with nonstimulated ML decreased platelet aggregation induced by collagen or thrombin in a concentration-dependent manner. The inhibitory effect increased with the incubation period of the cells, reaching a plateau at 5 minutes. T and non-T enriched ML suspensions exerted an inhibitory effect similar to the total population of ML. Supernatants from ML or mixed cell suspensions also diminished platelet aggregation. 6-keto PGF1 alpha concentration in the supernatants was less than 10 pg/ml. Hemoglobin, L-arginine and cytochrome C did not modify the antiaggregating activity of ML, whereas superoxide dismutase potentiated the inhibition of aggregation mediated by ML. The inhibitory effect was not modified by monoclonal antibody (MoAb) against the lymphocyte function-associated antigen 1, alpha subunit (LFA-1 alpha) or by a MoAb directed against P-selectin. Our results demonstrated that ML inhibited platelet aggregation, at least partially, by the release of a soluble factor(s) distinct of prostacyclin or nitric oxide. Surface adhesion molecules seem also not to be involved.

Asunto(s)

Leucocitos Mononucleares/fisiología , Agregación Plaquetaria , 6-Cetoprostaglandina F1 alfa/farmacología , Anticuerpos Monoclonales/farmacología , Arginina/farmacología , Colágeno/farmacología , Medios de Cultivo Condicionados/farmacología , Grupo Citocromo c/farmacología , Fibrinógeno/farmacología , Hemoglobinas/farmacología , Humanos , Antígeno-1 Asociado a Función de Linfocito/inmunología , Subgrupos Linfocitarios/fisiología , Monocitos/fisiología , Selectina-P , Agregación Plaquetaria/efectos de los fármacos , Glicoproteínas de Membrana Plaquetaria/antagonistas & inhibidores , Glicoproteínas de Membrana Plaquetaria/inmunología , Superóxido Dismutasa/farmacología , Trombina/farmacología

RESUMEN

A single population of alpha 2 adrenoceptors was characterized in intact B lymphocytes from patients with chronic lymphocytic leukemia (B-CLL) by binding and saturation studies with 3H labelled yohimbine and by competition studies with alpha adrenergic antagonists. While the affinity of B-CLL alpha 2 adrenoceptors was low (KD: 9.81 nM-20.98 nM), each cell expressed a large number of receptors. No binding of the alpha 1 adrenoceptor antagonist prazosin was observed and the binding properties of beta adrenergic receptors (assayed with 3H-labelled dihydroalprenolol), were similar to those described for normal lymphocytes. Reaction of B-CLL with the beta adrenergic agonist isoproterenol raised the levels of cAMP in 11/13 patients tested, and in 8 of these, incubation with the alpha 2 adrenergic agonist clonidine prevented the effect and reduced the basal cAMP levels. The presence of active alpha 2 adrenoceptors on B-CLL lymphocytes may be involved in the regulation of metabolic pathways that affect cell functions and favor neoplastic growth.

Asunto(s)

Leucemia Linfocítica Crónica de Células B/metabolismo , Linfocitos/metabolismo , Receptores Adrenérgicos alfa/metabolismo , Receptores Adrenérgicos beta/metabolismo , Anciano , Anciano de 80 o más Años , Clonidina/farmacología , AMP Cíclico/metabolismo , Femenino , Humanos , Isoproterenol/farmacología , Masculino , Persona de Mediana Edad , Propranolol/farmacología , Temperatura , Yohimbina/metabolismo

RESUMEN

Recently, we have shown that soluble factors released by human lymphocytes after lectin stimulation could increase the contractile tension of rat atria "in vitro" and that interleukin-2 (IL-2) could be part of this reaction. The effect of IL-2 was potentiated by the Ca2+ ionophore A23187 or free arachidonic acid (AA). In this study we demonstrate that the action of IL-2 can be prevented by pre-incubation of the heart tissue with monoclonal anti-IL-2 receptor (anti-p55), suggesting that binding to the IL-2 receptor is necessary for the induction of the biologic effect. In the presence of A23187 or AA, the effect of the synthetic diacylglyceride oleoyl-acetyl-glycerol (OAG) was similar to that of IL-2. Elimination of phospholipase C activity by pre-incubation of the atria with 2-nitro-carboxyphenyl,N,N'-diphenylcarbamate (NCDC) abrogated the effects of IL-2 in the presence of A23187 or AA, but was ineffective when OAG + A23187 or OAG + AA was used. Inhibition of atrial phospholipase A2 activity with p-bromo-phenacylbromide (BPB) blocked the response of atria to either IL-2 + A23187 or OAG + A23187 but was not effective when AA was used as second signal (IL-2 + AA or OAG + AA). Both the OAG and the IL-2 positive inotropic effects could be prevented by the protein kinase C inhibitor 1-(5-isoquinolinesulfonyl)-2-methyl-piperazine (H7) but were poorly inhibited by N-(2-guanidinoethyl)-5-isoquinolinesulfonamide (HA1004), an inhibitor of the cyclic nucleotide-dependent protein kinases.(ABSTRACT TRUNCATED AT 250 WORDS)

Asunto(s)

Interleucina-2/farmacología , Contracción Miocárdica/efectos de los fármacos , Fosfolipasas A/fisiología , Proteínas Quinasas/fisiología , Fosfolipasas de Tipo C/fisiología , Animales , Ácidos Araquidónicos/metabolismo , Atrios Cardíacos/efectos de los fármacos , Lipooxigenasa/metabolismo , Fosfolipasas A/antagonistas & inhibidores , Fosfolipasas A2 , Prostaglandina-Endoperóxido Sintasas/metabolismo , Inhibidores de Proteínas Quinasas , Ratas , Receptores de Interleucina-2/metabolismo , Sistemas de Mensajero Secundario/efectos de los fármacos , Fosfolipasas de Tipo C/antagonistas & inhibidores

RESUMEN

We studied the effect of transformed lymphocytes from patients with chronic lymphocytic leukaemia (CLL) and the Raji cell (Raji) on the response of rat isolated atria to sodium arachidonate (AA). In contrast to normal lymphocytes, CLL cells and Raji cells decrease the contractile tension of rat isolated atria. Addition of exogenous AA (1.98 X 10(-6) M) to Raji, further reduced the isometric developed tension. Time of culture of Raji was important, as the negative inotropic effect was greater at 72 h than at 24 h of culture. Living cells were required and cell-free supernatants were inactive. Preincubation of CLL cells or Raji with cyclooxygenase inhibitors (acetyl salycilic acid, indomethacin) or inhibitors of thromboxane (TX) synthesis (imidazole, L-8027) abolished the negative inotropic response suggesting the contribution of TXs. L-8027 also reduced the growth rate of Raji cells, indicating that TXs may play a role in the regulation of cell division. The production of TXs by CLL and Raji cells from both endogenous and exogenous sources provided additional support to this hypothesis and suggested that activation of this metabolic pathway may be related to cell transformation.

Asunto(s)

Activación de Linfocitos/fisiología , Linfocitos/metabolismo , Contracción Miocárdica/efectos de los fármacos , Tromboxanos/biosíntesis , Animales , Antiinflamatorios no Esteroideos/farmacología , Ácido Araquidónico , Ácidos Araquidónicos/metabolismo , Ácidos Araquidónicos/farmacología , División Celular/efectos de los fármacos , Atrios Cardíacos/efectos de los fármacos , Humanos , Indoles/farmacología , Leucemia Linfocítica Crónica de Células B/metabolismo , Masculino , Ratas , Ratas Endogámicas , Tromboxanos/sangre , Células Tumorales Cultivadas

RESUMEN

Activated lymphocytes may have potent biologic effects outside the frame of the immune system. In these studies we analyzed the interaction of activated normal human lymphocytes and/or soluble products of lymphocyte activation on the contractile activity of isolated rat atria. The results indicate that phytohemagglutinin activated lymphocytes of the CD4 phenotype exert a positive inotropic effect on spontaneously beating atria. This effect is linked to steps of lymphocyte activation that precede cell division. Soluble factors released to the supernatant of stimulated lymphocytes can substitute for the intact cells. Interleukin-2 (IL-2) appears to be an important component of the active supernatants, as their activity can be reduced by monoclonal anti-IL-2 or by preincubation of the heart tissue with monoclonal anti-IL-2 receptor (anti-Tac). Highly purified IL-2 was active at 10 units/ml. In order to induce a positive inotropic effect at lower doses of natural or recombinant IL-2 (2-3 units/ml), synergic factors were required (2 x 10(-6) M arachidonic acid, AA, or Ca ionophore A 23187). Indirect evidence indicates that IL-2 exerts its biologic effect by turning on the phosphoinositide cycle and activating protein kinase C in the heart tissue target. It is postulated that similar mechanisms may be activated in inflammatory myocardiopathies or during the treatment of cancer with massive doses of IL-2.

Asunto(s)

Interleucina-2/farmacología , Activación de Linfocitos/efectos de los fármacos , Contracción Miocárdica , Fitohemaglutininas/farmacología , Animales , Humanos , Ratas

RESUMEN

The positive inotropic effect of cell-free supernatants from lectin-activated lymphocytes is lost by dialysis and can be partially restored by addition of arachidonic acid (AA). Interleukin-2 (IL-2) in the presence of AA could stimulate the response of the heart while the interferons (alpha-IFN or gamma-IFN) were ineffective. The activity of PHA-L-SN and that of IL-2 + AA was neutralized by anti-IL-2 MAb. These results suggest a key role for IL-2 in the stimulation of heart contractility by supernatants from activated lymphocytes.

Asunto(s)

Interleucina-2/fisiología , Lectinas/farmacología , Linfocitos/fisiología , Contracción Miocárdica/efectos de los fármacos , Animales , Ácido Araquidónico , Ácidos Araquidónicos/farmacología , Técnicas In Vitro , Interferón Tipo I/farmacología , Masculino , Ratas , Estimulación Química

RESUMEN

Activated lymphocytes may have potent biologic effects outside the frame of the immune system. In these studies we analyzed the interaction of activated normal human lymphocytes and/or soluble products of lymphocyte activation on the contractile activity of isolated rat atria. The results indicate that phytohemagglutinin activated lymphocytes of the CD4 phenotype exert a positive inotropic effect on spontaneously beating atria. This effect is linked to steps of lymphocyte activation that precede cell division. Soluble factors released to the supernatant of stimulated lymphocytes can substitute for the intact cells. Interleukin-2 (IL-2) appears to be an important component of the active supernatants, as their activity can be reduced by monoclonal anti-IL-2 or by preincubation of the heart tissue with monoclonal anti-IL-2 receptor (anti-Tac). Highly purified IL-2 was active at 10 units/ml. In order to induce a positive inotropic effect at lower doses of natural or recombinant IL-2 (2-3 units/ml), synergic factors were required (2 x 10(-6) M arachidonic acid, AA, or Ca ionophore A 23187). Indirect evidence indicates that IL-2 exerts its biologic effect by turning on the phosphoinositide cycle and activating protein kinase C in the heart tissue target. It is postulated that similar mechanisms may be activated in inflammatory myocardiopathies or during the treatment of cancer with massive doses of IL-2.