The role of the different CD3γ domains in TCR expression and signaling.

The CD3 subunits of the T-cell antigen receptor (TCR) play a central role in regulation of surface TCR expression levels. Humans who lack CD3γ (γ-) show reduced surface TCR expression levels and abolished phorbol ester (PMA)-induced TCR down-regulation. The response to PMA is mediated by a double leucine motif in the intracellular (IC) domain of CD3γ. However, the molecular cause of the reduced TCR surface expression in γ- lymphocytes is still not known. We used retroviral vectors carrying wild type CD3γ or CD3δ or the following chimeras (EC-extracellular, TM-transmembrane and IC): δECγTMγIC (δγγ for short), γγδ, γδδ and γγ-. Expression of γγγ, γγδ, γδδ or γγ- in the γ- T cell line JGN, which lacks surface TCR, demonstrated that cell surface TCR levels in JGN were dependent on the EC domain of CD3γ and could not be replaced by the one of CD3δ. In JGN and primary γ- patient T cells, the tested chimeras confirmed that the response to PMA maps to the IC domain of CD3γ. Since protein homology explains these results better than domain structure, we conclude that CD3γ contributes conformational cues that improve surface TCR expression, likely at the assembly or membrane transport steps. In JGN cells all chimeric TCRs were signalling competent. However, an IC domain at CD3γ was required for TCR-induced IL-2 and TNF-α production and CD69 expression, indicating that a TCR without a CD3γ IC domain has altered signalling capabilities.

Generation of a human iPSC line (IMEDEAi008-A) derived from natural homozygous CCR5-Δ32 PBMCs enriched in the pro-erythroblast population.

A 32 base pair deletion in the C-C chemokine receptor type gene (CCR5-Δ32), the main Human Immunodeficiency Virus (HIV) co-receptor results in a non-functional protein. Individuals homozygous for the CCR5-Δ32 mutation are resistant to HIV infection. Here we report the generation, from pro-erythroblast enriched Peripheral Blood Mononuclear Cells (PBMCs) from a naturally occurring CCR5-Δ32/Δ32 individual, of the fully characterized iPSC line IMEDEAi008-A. The new line has normal karyotype, carry the Δ32 mutation in homozygosity, is free of plasmid integrations, express high levels of pluripotency markers and can differentiate into all three germ layers.

Generation of one iPSC line (IMEDEAi007-A) by Sendai Virus transduction of PBMCs from a Psoriasis donor.

Psoriasis is a chronic inflammatory skin disease that speeds up the life cycle of skin cells, forming scales and red patches that are itchy and sometimes painful. It is a complex disease of autoimmune origin and genetic predisposition with more than 10 different loci associated. Here we described the production of an iPSC line generated by Sendai Virus (Klf4, Oct3/4, Sox2 and c-Myc) reprogramming of Peripheral Blood Mononuclear Cells (PBMCs) from a Psoriasis patient. The iPSC line generated has normal 46XY karyotype, is free of SeV genome and transgenes insertions, express high levels of pluripotency markers and can differentiate into all three germ layers.

iPSC-Derived Intestinal Organoids from Cystic Fibrosis Patients Acquire CFTR Activity upon TALEN-Mediated Repair of the p.F508del Mutation.

Cystic fibrosis (CF) is the main genetic cause of death among the Caucasian population. The disease is characterized by abnormal fluid and electrolyte mobility across secretory epithelia. The first manifestations occur within hours of birth (meconium ileus), later extending to other organs, generally affecting the respiratory tract. It is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. CFTR encodes a cyclic adenosine monophosphate (cAMP)-dependent, phosphorylation-regulated chloride channel required for transport of chloride and other ions through cell membranes. There are more than 2,000 mutations described in the CFTR gene, but one of them, phenylalanine residue at amino acid position 508 (p.F508del), a recessive allele, is responsible for the vast majority of CF cases worldwide. Here, we present the results of the application of genome-editing techniques to the restoration of CFTR activity in p.F508del patient-derived induced pluripotent stem cells (iPSCs). Gene-edited iPSCs were subsequently used to produce intestinal organoids on which the physiological activity of the restored gene was tested in forskolin-induced swelling tests. The seamless restoration of the p.F508del mutation resulted in normal expression of the mature CFTR glycoprotein, full recovery of CFTR activity, and a normal response of the repaired organoids to treatment with two approved CF therapies: VX-770 and VX-809.

New Bicistronic TALENs Greatly Improve Genome Editing.

Genome editing has become one of the most powerful tools in present-day stem cell and regenerative medicine research, but despite its rapid acceptance and widespread use, some elements of the technology still need improvement. In this unit, we present data regarding the use of a new, more efficient type of transcription activator-like effector nuclease (TALEN) for gene editing. Our group has generated bicistronic genes in which classical TALEN coding sequences are linked by 2A elements to different reporter molecules, such as fluorochromes (TALEN-F) or membrane receptors (TALEN-M). This structure results in two proteins transcribed from the same transcript, of which the second (the reporter) can be used as the target for selection by fluorescence-assisted cell sorting (FACS) or magnetic-activated cell sorting (MACS). The application of these new TALEN genes allows a rapid enrichment of cells in which both members of the TALEN pair are active, thus eliminating the need for lengthy selection in culture and laborious characterization of a large number of clones. © 2020 by John Wiley & Sons, Inc. Basic Protocol 1: Generation of new TALENs Basic Protocol 2: Genome editing using TALEN-F Alternate Protocol 1: Generation of TALEN-M Support Protocol 1: mRNA in vitro transcription (IVT) of TALEN-T2A-reporter expression vector Alternate Protocol 2: Editing of primary T cells using TALEN-M Basic Protocol 3: Verifying gene editing Support Protocol 2: Rapid expansion protocol for edited T-cells.

Generation of one iPSC line (IMEDEAi006-A) from an early-onset familial Alzheimer's Disease (fAD) patient carrying the E280A mutation in the PSEN1 gene.

The mutation E280A in PSEN1 (presenilin-1) is the most common cause of early-onset familial Alzheimer's Disease (fAD). It presents autosomal dominant inheritance and frequently leads to the manifestation of the disease in relatively young individuals. Here we report the generation of one PSEN1 E280A iPSC line derived from an early-onset patient. OriP/EBNA1-based episomal plasmids containing OCT3/4, SOX2, KLF4, L-MYC, LIN28, BCL-xL and shp53 were used to reprogram oral mucosa fibroblasts. The iPSC line generated has normal karyotype, carry the E280A mutation, is free of plasmid integration, express high levels of pluripotency markers and can differentiate into all three germ layers.

Generation of two induced pluripotent stem cells lines from a Mucopolysaccharydosis IIIB (MPSIIIB) patient.

Mucopolysaccharydosis IIIB is the second most frequent form of Sanfilippo syndrome, a degenerative, pediatric lysosomal storage disease (LSD) characterized by severe neurological disorders and death. We have generated two iPSCs lines derived from dermal fibroblast from a MPSIIIB homozygous (P358L) donor. Cells were reprogrammed with OriP/EBNA1-based episomal plasmids containing: OCT3/4, SOX2, KLF4, L-MYC, LIN28, BCL-xL and shp53. Both cell lines are homozygous for the P358L mutation of the α-N-acetylglucosaminidase (NAGLU) gene, have normal karyotype, are free of plasmid integration, express high levels of pluripotency-associated markers and can differentiate into the three germ layers. RESOURCE TABLE: RESOURCE UTILITY: Although the generation of iPSCs has been reported for some lysosomal storage diseases (LSD) in general, and from other mutations of the NAGLU gene in particular (Lemonnier et al., 2011), this is the first time that NAGLU Pro358Leu MPSIIIB-iPSCs lines have been generated and fully characterized demonstrating their quality as iPS cells. RESOURCE DETAILS: Mucopolysaccharidosis IIIB (MPSIII, Sanfilippo syndrome type B) is a pediatric neurodegenerative disorder caused by a deficiency in NAGLU, an enzyme required for lysosomal degradation of heparin sulphate (HS). When the enzyme is absent or malfunctioning, HS accumulates in the cells of several tissues, with devastating effects in the brain and central nervous system. MPSIIIB is inherited in an autosomal recessive manner and presents an incidence between 0.03 and 0.78 cases per 1 × 105 live births (Fedele, 2015) depending on the country. Currently there is no therapy available. The NAGLU gene was identified in 1996, is located on chromosome 17q21.1 and contains 6 exons. More than 150 NAGLU mutations have been reported, being most of them missense (Valstar et al., 2010). All of them lead to MPSIIIB but, unlike MPSIIIA, none is predominant. The two iPSCs lines described in this report, IMEDEAi005-A and IMEDEAi005-B, (See Table 1) were generated from skin fibroblast obtained from a clinically affected homozygous donor. The mutant allele consists on a C > T transversion at nucleotide 1073 (1073 > T) resulting in a substitution of leucine for proline at codon 358 (Pro358Leu). Skin fibroblasts were reprogrammed to iPSCs by nucleofection with four OriP/EBNA1 (Epstein-Barr nuclear antigen-1) based episomal plasmids encoding 5 reprogramming genes (OCT3/4, SOX2, KLF4, L-Myc, LIN28 and BCL-xL), in addition to a short hairpin RNA against p53. The iPSCs lines showed morphology (Fig. 1A) and growth behaviour typical of human Embryonic Stem Cells (hESC), as well as normal female karyotype (46, XX) (Fig. 1B). After 12 passages, PCR analysis confirmed that both iPSCs lines had completely lost the episomal vectors (Fig. 1C). The identity of iPS cells and their parental fibroblasts was confirmed by STR analysis (Table 2, data not shown) in addition to the identification of the disease-associated mutation in the NAGLU gene by DNA sequencing (Fig. 1D). Regarding the iPSC phenotype, both lines expressed the pluripotency-associated markers: OCT3/4, NANOG, SOX2 and TRA-1-60 (Fig. 1E), and TRA-1-81 quantified by flow cytometry (Fig. 1G), resulting in 88.17% and 83.4% of TRA-1-81 positive cells in IMEDEAi005-A and IMEDEAi005-B respectively. Finally, the differentiation capacity of iPSCs lines was analyzed by embryoid body (EBs) formation. Expression of markers specific of the three germ layers was observed after at least 10 days of spontaneous differentiation (Fig. 1F). Mycoplasma analysis was negative for both iPSCs lines (Supplementary Fig. S1). Skin fibroblasts were reprogrammed to iPSCs by nucleofection with four OriP/EBNA1 (Epstein-Barr nuclear antigen-1) based episomal plasmids encoding 5 reprogramming genes (OCT3/4, SOX2, KLF4, L-Myc, LIN28 and BCL-xL), in addition to a short hairpin RNA against p53. The iPSCs lines showed morphology (Fig. 1A) and growth behaviour typical of human Embryonic Stem Cells (hESC), as well as normal female karyotype (46, XX) (Fig. 1B). After 12 passages, PCR analysis confirmed that both iPSCs lines had completely lost the episomal vectors (Fig. 1C). The identity of iPS cells and their parental fibroblasts was confirmed by STR analysis (Table 2, data not shown) in addition to the identification of the disease-associated mutation in the NAGLU gene by DNA sequencing (Fig. 1D). Regarding the iPSC phenotype, both lines expressed the pluripotency-associated markers: OCT3/4, NANOG, SOX2 and TRA-1-60 (Fig. 1E), and TRA-1-81 quantified by flow cytometry (Fig. 1G), resulting in 88.17% and 83.4% of TRA-1-81 positive cells in IMEDEAi005-A and IMEDEAi005-B respectively. Finally, the differentiation capacity of iPSCs lines was analyzed by embryoid body (EBs) formation. Expression of markers specific of the three germ layers was observed after at least 10 days of spontaneous differentiation (Fig. 1F). Mycoplasma analysis was negative for both iPSCs lines (Supplementary Fig. S1). In conclusion, we have successfully generated and characterized, for the first time to our knowledge, two human iPSCs lines from a MPSIIIB donor homozygous for the P358L NAGLU mutation. The new lines will complement the existing murine MPS IIIB model, with their potential to be used in a development of a purely human in vitro model of the disease.

Encefalitis progresiva por anticuerpos anti-DPPX: un caso con buena respuesta al tratamiento con rituximab / Progressive encephalitis due to anti-DPPX antibodies: a case with good response to treatment with rituximab

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Clinical and radiological control of highly active relapsing-remitting multiple sclerosis with first-line natalizumab.

A 33-year-old man with gait instability, weakness of the left lower extremity, decreased visual acuity in the left eye, and urgency and urine incontinence was diagnosed of relapsing-remitting multiple sclerosis. He was treated with natalizumab (300 mg intravenously every 4 weeks) as first-line therapy, which reached at 6 months a favorable clinical evolution and dramatic radiological improvement (T2-weighted lesion load decreased by 50% and no gadolinium-enhancing T1 lesions) sustained over the course of 8 years. This clinical case shows the efficacy of natalizumab in a real-world setting and, particularly, the sustained effect of this drug in the long term as demonstrated by persistent radiological improvement. Natalizumab can be considered as the treatment of choice in relapsing-remitting multiple sclerosis forms presenting with two relapses and gadolinium-enhancing (Gd+) lesions.

Prevalencia de la esclerosis múltiple en la Región de Murcia / Prevalence of multiple sclerosis in the Region of Murcia

Introducción. La esclerosis múltiple (EM) es una enfermedad inflamatoria desmielinizante del sistema nervioso central con patogenia inmunomediada. Recientes estudios indican un aumento de su prevalencia, y numerosos trabajos relacionan el virus de Epstein-Barr (VEB) con su etiología. Objetivo. Análisis de prevalencia de la EM en la Región de Murcia, incluyendo la descripción de las características clínicas en el momento del inicio de la enfermedad, y del estado serológico del VEB de los pacientes con EM. Pacientes y métodos. Estudio epidemiológico retrospectivo, tomando como muestra la población residente en el área sanitaria centro-oeste de la Región de Murcia (257.865 habitantes). Se analizan datos clínicos y serológicos extraídos de diferentes fuentes. Resultados. Prevalencia de la EM en la población estudiada: 88 casos/100.000 habitantes. Prevalencia de la EM junto con el síndrome desmielinizante aislado: 98,4 casos/100.000 habitantes. Incidencia media de la EM: 5,8 casos/100.000 habitantes/año. En el inicio de la EM, el 67,8% eran mujeres, el 81,9% presentaba un curso recurrente-remitente, la edad media era de 31,4 años, el sistema funcional más frecuentemente afectado era el sensitivo (45,1%), el inicio fue monofocal en el 55,4% y el grado de discapacidad en la Expanded Disability Status Scale era de 2,1 puntos. La seroprevalencia del VEB fue del 99,3%. La reactivación de la infección por VEB se relacionó con actividad clínica de EM en 10 pacientes (45,4%). Conclusiones. Actualmente, la prevalencia de la EM en la Región de Murcia es similar a la estimada en otras comunidades autónomas españolas. El estudio confirma la tendencia de incremento de prevalencia observada en las últimas décadas (AU)

Introduction. Multiple sclerosis (MS) is a demyelinating inflammatory disease of the central nervous system with immunemediated pathogenesis. Recent research points to an increase in its prevalence, and a number of studies relate EpsteinBarr virus (EBV) with its aetiology. Aims. This study seeks to analyse the prevalence of MS in the Region of Murcia, and includes a description of the clinical characteristics at the time of onset of the disease, and of the EBV serological status of patients with MS. Patients and methods. We conducted a retrospective epidemiological study based on a sample consisting of the population living within the central-west healthcare area of the Region of Murcia (257,865 inhabitants). Clinical and serological data extracted from different sources were analysed. Results. Prevalence of MS in the population under study: 88 cases/100,000 inhabitants. Prevalence of MS together with isolated demyelinating syndrome: 98.4 cases/100,000 inhabitants. Mean incidence of MS: 5.8 cases/100,000 inhabitants/ year. At the onset of MS, 67.8% were females, 81.9% presented a relapsing-remitting course, the mean age was 31.4 years, the sensory system was the most frequently compromised (45.1%), onset was monofocal in 55.4% and the degree of disability on the Expanded Disability Status Scale was 2.1 points. The seroprevalence of EBV was 99.3%. The reactivation of EBV infection was related to the clinical activity of MS in 10 patients (45.4%). Conclusions. Currently, the prevalence of MS in the Region of Murcia is similar to that estimated in other Spanish autonomous regions. The study confirms the trend of increased prevalence observed over the last few decades (AU)

Plasma exchange for steroid-refractory relapses in multiple sclerosis: an observational, MRI pilot study.

BACKGROUND: Numerous studies have shown that plasma exchange (PE) is effective as second-line treatment of severe exacerbations of multiple sclerosis (MS) or other idiopathic inflammatory demyelinating diseases of the central nervous system that are nonresponsive to steroid therapy. OBJECTIVE: The goal of this study was to analyze the effect of PE on clinically active radiologic lesions in steroid-refractory relapses of MS and idiopathic inflammatory demyelinating diseases of the central nervous system. METHODS: This was a prospective, observational pilot study in which the primary end point was the degree of radiologic resolution of active lesions after PE. RESULTS: A total of 15 patients were included (median age, 36.9 years [age range, 21-67 years]; 60% women). Five (33.3%) of the 15 patients had relapsing-remitting MS, 2 (13.3%) had clinically isolated syndrome that presented with transverse myelitis, 2 (13.3%) had recurrent myelitis, 1 (6.7%) had transverse myelitis, 1 (6.7%) had longitudinally extensive transverse myelitis, 1 (6.7%) had acute disseminated encephalomyelitis, 1 (6.7%) had Baló's concentric sclerosis, and 2 (13.3%) had neuromyelitis optica. Mean increase on the expanded disability status scale scores due to relapses was 4.8 (2.53). After PE, 93.3% showed a marked to moderate clinical improvement, and 46.7% recovered their baseline expanded disability status scale score 3 months post-PE. On the post-PE MRI, 60% showed radiologic resolution (80% mass-effect lesions, 83.3% new-onset disease, and 100% neuromyelitis optica), 20% had partial resolution, and 20% no resolution. A significant relationship was not obtained between degree of resolution of radiologic lesions and the variables: clinical response to PE, new-onset disease, mass-effect lesions, number of PE sessions, and early initiation of PE. CONCLUSION: A marked to moderate clinical improvement post-PE accompanied by a lack of radiologic resolution of the active lesion is not indicative of poor prognosis.

Pancreaticoduodenectomy for metastasis of uterine leiomyosarcoma to the pancreas.

Metastasis of uterine leiomyosarcoma to the pancreas is rare. A 46-year-old woman was diagnosed with uterine leiomyosarcoma and underwent surgery. Thereafter, recurrences in the lung and subsequently in the pancreas were diagnosed. These lesions were resected and diagnosed as metastasis of uterine leiomyosarcoma. We report a rare case of uterine leiomyosarcoma with metastasis to the lung and pancreas, both of which were resected using aggressive surgery.

[Homocysteine and cognitive impairment in Parkinson's disease]. / Homocisteína y deterioro cognitivo en la enfermedad de Parkinson.

INTRODUCTION: The relationship between homocysteine (Hc) and vascular diseases has been known for more than 30 years. Lately, Hc has also been related to cognitive and motor impairment. In Parkinson's disease (PD), chronic treatment with levodopa could induce higher levels of Hc, and thus may increase risk of cognitive impairment. AIMS: To confirm that PD patients treated with levodopa have higher levels of Hc and to establish a relationship between Hc, folic acid and vitamin B12 levels. Also, we studied a possible link between those variables and cognitive function. PATIENTS AND METHODS: 58 patients with diagnosis of PD were included (45 under treatment with levodopa). Basal levels of Hc, vitamin B12 and folic acid were determined. Forty five patients underwent neuropsychological evaluation. RESULTS: Hc levels were significantly higher in patients taking levodopa and were not related to levodopa dosage or treatment duration. There was a negative correlation between Hc levels and those of vitamin B12 and folic acid in men but we found no such correlation in women. Entacapone was not found to reduce Hc levels. Hc levels were significantly higher in patients with cognitive impairment (9 out of 45 patients). CONCLUSIONS: Our study confirms presence of high levels of Hc in PD patients under treatment with levodopa, more evident in patients with cognitive impairment.

Homocisteína y deterioro cognitivo en la enfermedad de Parkinson / Homocysteine and cognitive impairment in Parkinson’s disease

Introducción. La relación entre homocisteína (Hc) y enfermedades vasculares se conoce desde hace más de 30 años. En los últimos años se ha relacionado también con deterioro cognitivo y motor. En la enfermedad de Parkinson (EP), el tratamiento crónico con levodopa puede inducir un incremento en los niveles de Hc, implicando un riesgo añadido para el deterioro cognitivo. Objetivos. Confirmar la elevación de los niveles de Hc en pacientes con EP tratados con levodopa, su relación con los niveles de vitamina B12 y folato, y si podía existir una relación entre dichas variables y la función cognitiva. Pacientes y métodos. Se incluyeron 58 pacientes diagnosticados de EP (45 en tratamiento con levodopa), se determinaron los niveles basales de Hc, vitamina B12 y folato, y se realizó una evaluación neuropsicológica en 45 de los pacientes. Resultados. El nivel de Hc estaba significativamente más elevado en los pacientes en tratamiento con levodopa, sin relación con la dosis ni el tiempo en tratamiento. Existía una correlación negativa entre los valores de Hc y vitamina B12 y folato en los hombres, que no se observó en las mujeres. Tomar entacapona no redujo los niveles de Hc. El nivel de Hc estaba significativamente más elevado en los pacientes con deterioro cognitivo (9 de los 45 evaluados).Conclusiones. Nuestro estudio confirma la elevación de los niveles de Hc en pacientes con EP en tratamiento con levodopa, y de forma más evidente en los pacientes con deterioro cognitivo (AU)

Introduction. The relationship between homocysteine (Hc) and vascular diseases has been known for more than 30 years. Lately, Hc has also been related to cognitive and motor impairment. In Parkinson’s disease (PD), chronic treatment with levodopa could induce higher levels of Hc, and thus may increase risk of cognitive impairment. Aims. To confirm that PD patients treated with levodopa have higher levels of Hc and to establish a relationship between Hc, folic acid and vitamin B12 levels. Also, we studied a possible link between those variables and cognitive function. Patients and methods. 58 patients with diagnosis of PD were included (45 under treatment with levodopa). Basal levels of Hc, vitamin B12 and folic acid were determined. Forty five patients underwent neuropsychological evaluation. Results. Hc levels were significantly higher in patients taking levodopa and were not related to levodopa dosage or treatment duration. There was a negative correlation between Hc levels and those of vitamin B12 and folic acid in men but we found no such correlation in women. Entacapone was not found to reduce Hc levels. Hc levels were significantly higher in patients with cognitive impairment (9 out of 45 patients). Conclusions. Our study confirms presence of high levels of Hc in PD patients under treatment with levodopa, more evidentin patients with cognitive impairment (AU)

[Hepatobiliary cystoadenomas]. / Cistoadenomas hepatobiliares.

Cystoadenomas of the liver are rare cystic tumors that have seldom been reported. Accurate preoperative diagnosis is difficult because they are usually mistaken for more frequent lesions. Due to their malignant potential, complete surgical removal of the lesion is required. Correct diagnosis is guided by clinical history, radiological imaging, and laboratory parameters. We report two of these rare cases and discuss the spectrum of presentation, pathological features and treatment of these tumors.

Herpesvirus saimiri-transformed CD8+ T cells as a tool to study Chediak-Higashi syndrome cytolytic lymphocytes.

Cytolytic CD8+ T lymphocytes are the main cell type involved in the fatal lymphoproliferative-accelerated phase of the Chediak-Higashi syndrome (CHS). To generate a cellular tool to study the defects of this T cell subset in vitro, we have used Herpesvirus saimiri, a lymphotropic virus that transforms human T lymphocytes into extended growth and in addition, endows them with natural killer (NK) features. Transformed CHS CD8+ T cells were generated and characterized in comparison with healthy controls. The results showed that transformed CHS T cells maintained the defects described in primary CHS lymphocytes, such as giant secretory lysosomes and impaired NK and T cell receptor/CD3-induced, perforin-mediated cytolytic activity [which, however, could be restored after extended culture in the presence of interleukin-2 (IL-2)]. Upon activation with phorbol ester plus calcium ionophore or upon extended culture with IL-2, transformed CHS T cells showed normal, perforin-independent plasma membrane CD178/CD95L/FasL-mediated cytolytic activity but negligible secretion of microvesicle-bound CD95L. Transformed (and primary) CHS T cells were otherwise normal for cytolysis-independent activation functions, such as proliferation, surface expression of several activation markers including major histocompatibility complex class II, and cytokine or surface activation-marker induction. Therefore, the CHS protein [CHS1/LYST (for lysosomal traffic regulator)] can be dispensable for certain NK and T cell cytolytic activities of activated CHS CD8+ T lymphocytes, but it seems to be required for microvesicle secretion of CD95L. We conclude that transformed CHS T cells may be useful as a tool to study in vitro the relative role of CHS1/LYST in NK and T lymphocyte cytolysis and antigen presentation.

TCR dynamics in human mature T lymphocytes lacking CD3 gamma.

The contribution of CD3gamma to the surface expression, internalization, and intracellular trafficking of the TCR/CD3 complex (TCR) has not been completely defined. However, CD3gamma is believed to be crucial for constitutive as well as for phorbol ester-induced internalization. We have explored TCR dynamics in resting and stimulated mature T lymphocytes derived from two unrelated human congenital CD3gamma-deficient (gamma(-)) individuals. In contrast to gamma(-) mutants of the human T cell line Jurkat, which were selected for their lack of membrane TCR and are therefore constitutively surface TCR negative, these natural gamma(-) T cells constitutively expressed surface TCR, mainly through biosynthesis of new chains other than CD3gamma. However, surface (but not intracellular) TCR expression in these cells was less than wild-type cells, and normal surface expression was clearly CD3gamma-dependent, as it was restored by retroviral transduction of CD3gamma. The reduced surface TCR expression was likely caused by an impaired assembly or membrane transport step during recycling, whereas constitutive internalization and degradation were apparently normal. Ab binding to the mutant TCR, but not phorbol ester treatment, caused its down-modulation from the cell surface, albeit at a slower rate than in normal controls. Kinetic confocal analysis indicated that early ligand-induced endocytosis was impaired. After its complete down-modulation, TCR re-expression was also delayed. The results suggest that CD3gamma contributes to, but is not absolutely required for, the regulation of TCR trafficking in resting and Ag-stimulated mature T lymphocytes. The results also indicate that TCR internalization is regulated differently in each case.

Torsión completa del epiplón mayor como causa de abdomen agudo. Contribución de la TC en el diagnóstico preoperatorio / Complete torsion of the greater omentum as a cause of acute abdomen. Contribution of computerized axial tomography to preoperative diagnosis

Se presenta el caso clínico de un varón joven intervenido por un cuadro de abdomen agudo secundario a la torsión completa del epiplón mayor, diagnosticado correctamente de manera preoperatoria mediante la realización de una tomografía axial computarizada. Se discuten los hallazgos clinicorradiológicos típicos, así como el tratamiento óptimo, haciendo una revisión de la bibliografía existente. (AU)