RESUMEN
Armadillos (Dasypus novemcinctus) manifest the full histopathological spectrum of leprosy, and are hosts of choice for in vivo propagation of Mycobacterium leprae. Though potentially useful as a model of leprosy pathogenesis, few armadillo-specific reagents exist. We have identified a region of high homology to the interferon gamma (IFN-gamma) of other mammals within the recently published armadillo whole genomic sequence. cDNA was made from ConA-stimulated armadillo peripheral blood mononuclear cells (PBMC), amplified, and cloned into a pET expression vector for transformation and over-expression in Escherichia coli. The recombinant protein (rDnIFN-gamma) was characterized by western blot and its biological function confirmed with bioassays including intracellular killing of Toxoplasma gondii and induction of indoleamine 2, 3-dioxygenase activity. In using rIFN-gamma to activate macrophages from mice, humans or armadillos, similar to humans, rIFN-gamma-activated armadillo MPhi did not produce nitrite and or inhibit the viability of M. leprae in vitro. Conversely, murine rIFN-gamma-activated mouse MPhi produced high levels of nitrite and killed intracellular M. leprae in vitro. These data indicate that the response of armadillo MPhi to rDnIFN-gamma is similar to that which occurs in humans, and demonstrates a potentially important value of the armadillo as a model in leprosy research.
Asunto(s)
Armadillos/metabolismo , Expresión Génica , Interferón gamma/metabolismo , Interferón gamma/farmacología , Macrófagos/efectos de los fármacos , Mycobacterium leprae/fisiología , Secuencia de Aminoácidos , Animales , Anticuerpos/inmunología , Armadillos/genética , Secuencia de Bases , Proliferación Celular/efectos de los fármacos , ADN Complementario/genética , Humanos , Indolamina-Pirrol 2,3,-Dioxigenasa/metabolismo , Interferón gamma/química , Interferón gamma/genética , Macrófagos/citología , Datos de Secuencia Molecular , Nitritos/metabolismo , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Isoformas de Proteínas/farmacología , Proteínas Recombinantes , Alineación de Secuencia , Homología de Secuencia de AminoácidoRESUMEN
The nine-banded armadillo (Dasypus novemcinctus) is the only immunologically intact animal that regularly develops lepromatous-type leprosy when inoculated with Mycobacterium leprae. However, the ability to exploit this model for understanding the pathogenesis of leprosy has been limited by a lack of suitable immunological reagents. Recently, efforts began to sequence the entire armadillo genome, and this sequence information will help make possible the development of a wide array of new immunological reagents suitable for use with armadillos. Using the available sequence data, a region of high homology to interleukin-2 of other mammals was identified. Primers were designed to amplify the coding region corresponding to the mature peptide and its exact sequence was confirmed. cDNA was made from ConA-stimulated armadillo PBMC. The amplified coding region was sub-cloned into a pET expression vector and transformed into Escherichia coli for over-expression. The subsequent product was characterized by SDS-PAGE and bioassays. Tritiated thymidine incorporation by CTLL-2 and armadillo lymphoblasts confirmed functionality of the recombinant product. The advent of the D. novemcinctus genome sequence and subsequent generation of immunological tools will assist in advancing the armadillo as a translational model for leprosy.