Immunoglobulin E-dependent regulation of the CCR3 chemokine receptor by interferon-gamma in atopic asthmatics.

BACKGROUND: The chemokine receptor CCR3 mediates the migration of cells that play an important role in the pathogenesis of asthma to inflammatory foci. Interferon (IFN)-gamma is known to downregulate the expression of some chemokine receptors. Therefore, we decided to analyze the regulation of CCR3 by IFN-gamma in asthmatics and to characterize the dependence of this process on immunoglobulin E (IgE) levels. METHODS: Atopic asthmatics were treated with IFN-gamma or placebo, and the IgE concentration in the blood was measured using an ultra-micro-ELISA for total IgE. Mononuclear cells from patients and controls were isolated by Ficoll-Hypaque gradient and incubated in the absence or presence of IFN-gamma for different periods of time. After incubation, the cells were washed and lysed for RT-PCR analysis, which was performed using a Perkin-Elmer kit. RESULTS: IFN-gamma treatment apparently improved the evaluated clinical variables; however, the differences were not significant compared to the placebo group. We found that IFN-gamma downregulated CCR3 mRNA expression ex vivo and in vivo in those patients with IgE levels higher than 500 IU/ml, whereas IFN-gamma upregulated CCR3 mRNA expression in patients with IgE levels lower than 500 IU/ml. Correspondence between ex vivo and in vivo results was observed using this approach. There was found to be a direct correlation between total serum IgE and CCR3 mRNA expression. CONCLUSIONS: In those asthmatic patients with high levels of IgE, who are thus susceptible to downregulation of CCR3 by IFN-gamma, a significant therapeutic effect with systemic IFN-gamma might be expected.

Construction, purification, and characterization of a chimeric TH1 antagonist.

BACKGROUND: TH1 immune response antagonism is a desirable approach to mitigate some autoimmune and inflammatory reactions during the course of several diseases where IL-2 and IFN-gamma are two central players. Therefore, the neutralization of both cytokines could provide beneficial effects in patients suffering from autoimmune or inflammatory illnesses. RESULTS: A chimeric antagonist that can antagonize the action of TH1 immunity mediators, IFN-gamma and IL-2, was designed, engineered, expressed in E. coli, purified and evaluated for its in vitro biological activities. The TH1 antagonist molecule consists of the extracellular region for the human IFNgamma receptor chain 1 fused by a four-aminoacid linker peptide to human 60 N-terminal aminoacid residues of IL-2. The corresponding gene fragments were isolated by RT-PCR and cloned in the pTPV-1 vector. E. coli (W3110 strain) was transformed with this vector. The chimeric protein was expressed at high level as inclusion bodies. The protein was partially purified by pelleting and washing. It was then solubilized with strong denaturant and finally refolded by gel filtration. In vitro biological activity of chimera was demonstrated by inhibition of IFN-gamma-dependent HLA-DR expression in Colo 205 cells, inhibition of IFN-gamma antiproliferative effect on HEp-2 cells, and by a bidirectional effect in assays for IL-2 T-cell dependent proliferation: agonism in the absence versus inhibition in the presence of IL-2. CONCLUSION: TH1 antagonist is a chimeric protein that inhibits the in vitro biological activities of human IFN-gamma, and is a partial agonist/antagonist of human IL-2. With these attributes, the chimera has the potential to offer a new opportunity for the treatment of autoimmune and inflammatory diseases.

Construction, purification, and characterization of a chimeric TH1 antagonist

TH1 immune response antagonism is a desirable approach to mitigate some autoimmune and inflammatory reactions during the course of several diseases where IL-2 and IFN-gamma are two central players. Therefore, the neutralization of both cytokines could provide beneficial effects in patients suffering from autoimmune or inflammatory illnesses. RESULTS: A chimeric antagonist that can antagonize the action of TH1 immunity mediators, IFN-gamma and IL-2, was designed, engineered, expressed in E. coli, purified and evaluated for its in vitro biological activities. The TH1 antagonist molecule consists of the extracellular region for the human IFNgamma receptor chain 1 fused by a four-aminoacid linker peptide to human 60 N-terminal aminoacid residues of IL-2. The corresponding gene fragments were isolated by RT-PCR and cloned in the pTPV-1 vector. E. coli (W3110 strain) was transformed with this vector. The chimeric protein was expressed at high level as inclusion bodies. The protein was partially purified by pelleting and washing. It was then solubilized with strong denaturant and finally refolded by gel filtration. In vitro biological activity of chimera was demonstrated by inhibition of IFN-gamma-dependent HLA-DR expression in Colo 205 cells, inhibition of IFN-gamma antiproliferative effect on HEp-2 cells, and by a bidirectional effect in assays for IL-2 T-cell dependent proliferation: agonism in the absence versus inhibition in the presence of IL-2. CONCLUSION: TH1 antagonist is a chimeric protein that inhibits the in vitro biological activities of human IFN-gamma, and is a partial agonist/antagonist of human IL-2. With these attributes, the chimera has the potential to offer a new opportunity for the treatment of autoimmune and inflammatory diseases(AU)

Respuesta inmune TH1 antagonismo es deseable un enfoque para mitigar algunas reacciones inflamatorias y autoinmunes durante el curso de varias enfermedades que la IL-2 e IFN-gamma son dos jugadores. Por lo tanto, la neutralización de citoquinas podrían proporcionar efectos beneficiosos en los pacientes que sufren de enfermedades autoinmunes o inflamatorias. RESULTADOS: Un antagonista quimérico que puede antagonizar la acción de los mediadores de inmunidad TH1, IFN-gamma e IL-2, se diseñan, planifican, expresado en E. coli, purificado y evaluados por su actividad biológica in vitro. El antagonista de TH1 molécula extracelular consiste en la región para el receptor de la cadena humana IFNgamma fundido 1 por un período de cuatro enlazador de aminoácidos del péptido a la N-terminal de 60 residuos de aminoácidos de la IL-2. El gen correspondiente fragmentos fueron aislados por RT-PCR y clonado en el vector pTPV-1. E. coli (cepa W3110) se transforma con este vector. El quimérico se expresó la proteína de alto nivel como cuerpos de inclusión. La proteína fue parcialmente purificada por granulación y lavado. Fue entonces disuelto con desnaturalizante fuerte y, por último, refolded por filtración en gel. Actividad biológica in vitro de la quimera fue demostrado por la inhibición de la IFN-gamma-dependiente de la expresión de HLA-DR en Colo 205 células, la inhibición de IFN-gamma efecto antiproliferativo sobre las células Hep-2, y por un efecto bidireccional en los ensayos para IL-2 T -dependiente de la proliferación celular: agonism en frente a la ausencia de inhibición en presencia de IL-2. CONCLUSIÓN: es un antagonista del TH1 quimérico proteína que inhibe la actividad biológica in vitro de la IFN-gamma, y es un agonista parcial / antagonista de la IL-2. Con estos atributos, la quimera tiene el potencial para ofrecer una nueva oportunidad para el tratamiento de enfermedades inflamatorias y autoinmunes

Bioequivalence of two recombinant granulocyte colony-stimulating factor formulations in healthy male volunteers.

To evaluate the equivalence of the pharmacokinetic, pharmacodynamic and safety properties of two recombinant G-CSF formulations in healthy male volunteers, a standard 2-way randomized crossover double-blind study, with a 3 week washout period, was conducted. A single 300 microg G-CSF dose was administered subcutaneously. Hebervital (Heber Biotec, Havana, formulation A) and Neupogen (Hoffmann-La Roche S.A, formulation B) were compared. Twenty-four healthy male volunteers were included. The serum G-CSF level was measured by enzyme immunoassay (EIA) during the first 36 h after administration. Absolute neutrophils (ANC), white blood cells (WBC) and CD34+ cells counts were the pharmacodynamic variables measured up to 120 h. Other clinical and laboratory determinations were used as safety criteria. The pharmacokinetic parameters for formulation A and B were very close to each other (i.e. AUC, 235.9 vs 270.0 ng.h/ml; C(max), 29.2 vs 33.4 ng/ml; T(max), 4.2 vs 4.7 h; half-life, 3.2 vs 2.8 h; CL, 260.9 vs 277.2 ml/h; V(d), 1.2 vs 1.1 l; and MRT, 7.58 vs 7.38 h). The confidence intervals for the means ratio of all these parameters were within or very close to the 0.8-1.25 acceptance range. The pharmacodynamics showed high similarity since ANC and WBC had the same profiles for both products and no differences were detected for the estimated parameters. The CD34+ cells count increments were evident for both formulations in a similar way as well. The treatments were well tolerated. Registered adverse events were similar; back/spine pain was the most frequent. According to the overall results these formulations could be considered as clinically comparable.