ABSTRACT
Tumor necrosis factor (TNF)-like weak inducer of apoptosis or TWEAK is a member of the TNF superfamily involved in the regulation of many biological processes. In mammals, TWEAK has been shown to play a role in some autoimmune or inflammatory conditions, but its immune role is not yet clearly defined. In teleost fish, although a few studies have identified homologues to mammalian TWEAK, their biological effects have never been investigated. In the current study, we have studied the transcriptional regulation of two TWEAK homologues (TWEAK 1 and 2) identified in rainbow trout (Oncorhynchus mykiss) throughout different tissues, in response to parasitic or viral infections, or in head kidney (HK) leukocytes stimulated with different stimuli. Although the transcription of both homologues was modulated when HK leukocytes were exposed to several immune stimuli, only TWEAK 1 was significantly modulated upon pathogenic exposure. Thus, we performed a characterization of the functions exerted by this cytokine in HK leukocytes. Recombinant TWEAK 1 strongly up-regulated the transcription of pro-inflammatory genes and antimicrobial peptides in HK leukocytes, with differential transcriptional effects in IgM+ B cells, IgM- lymphocytes and myeloid cells. TWEAK 1 also increased the survival and promoted the differentiation of B cells in HK leukocyte cultures. Our results demonstrate that in teleost fish, TWEAK 1 is involved in the response to different types of pathogens, through the modulation of antimicrobial and pro-inflammatory genes in different leukocytes subsets. Furthermore, a role for TWEAK as a B cell differentiation factor has also been established in rainbow trout.
Subject(s)
B-Lymphocytes/immunology , Cytokine TWEAK/immunology , Fish Proteins/immunology , Oncorhynchus mykiss/immunology , Animals , Fish Proteins/genetics , Head Kidney/immunology , Inflammation/immunology , Recombinant Proteins/immunologyABSTRACT
Muchos niños manifiestan linfadenopatías en algún momento de su infancia, debidas sobre todo a enfermedades infecciosas. Es precisa una buena historia clínica, exploración física y pruebas complementarias que permitan su diagnóstico diferencial. Se describen los casos de dos niños que presentaban un cuadro clínico similar de linfadenopatías regionales, sin fiebre ni exantemas. Ambos tenían como antecedente la picadura de garrapata en el cuero cabelludo. El cuadro clínico y la serología positiva a rickettsias nos llevaron al diagnóstico de linfoadenopatía transmitida por garrapatas, TIBOLA, DEBONEL o SENLAT. El diagnóstico serológico en nuestros casos se encuentra limitado por la existencia de reacciones cruzadas con las distintas especies de rickettsias, en concreto con R. conorii (que es la habitualmente detectada en nuestro medio) e incluso con otras bacterias. La evolución de ambos casos fue favorable con tratamiento de azitromicina durante cinco días. Pese a la dificultad que supone la interpretación de los resultados serológicos, el diagnóstico de esta rickettsiosis se puede hacer a la luz de los datos clínicos y epidemiológicos. Debe plantearse la utilización simultánea de otras técnicas para aumentar la sensibilidad diagnóstica como pueden ser en la actualidad las técnicas de reacción en cadena de la polimerasa en biopsia cutánea que nos darán el diagnóstico etiológico de la infección
Many children manifest lymphadenopathy at some point in their childhood, mainly due to infectious diseases. A correct clinical history, physical examination and complementary tests are required to allow differential diagnosis. We describe the cases of two children who presented a similar clinical presentation of regional lymphadenopathies without fever or rash. Both had as antecedent the tick bite on the scalp. The clinical presentation and the positive serology to Rickettsias led us to the diagnosis of lymphadenopathy transmitted by ticks, TIBOLA, DEBONEL or SENLAT. The serological diagnosis in our cases is limited by the existence of cross reactions with the different species of Rickettsias in particular with R. conorii (which is the one usually detected in our environment) and even with other bacteria. The evolution of both cases was favorable with treatment of azithromycin for five days. Despite the difficulty involved in the interpretation of serological results, the diagnosis of this rickettsiosis can be made in the light of clinical and epidemiological data. It should be considered the simultaneous use of other techniques to increase diagnostic sensitivity, such as PCR techniques in skin biopsy that will give us the etiological diagnosis of the infection
