RESUMEN
Programmed death 1 (PD-1) is an immune checkpoint molecule that negatively regulates T-cell immune function through the interaction with its ligand PD-L1. Blockage of this interaction unleashes the immune system to fight cancer. Immunotherapy using PD-1 blockade has led to a paradigm shift in the field of cancer drug discovery, owing to its durable effect against a wide variety of cancers with limited adverse effects. A brief history and development of PD-1 blockade, from the initial discovery of PD-1 to the recent clinical output of this therapy, have been summarized here. Despite its tremendous clinical success rate over other cancer treatments, PD-1 blockade has its own pitfall; a significant fraction of patients remains unresponsive to this therapy. The key to improve the PD-1 blockade therapy is the development of combination therapies. As this approach has garnered worldwide interest, here, we have summarized the recent trends in the development of PD-1 blockade-based combination therapies and the ongoing clinical trials. These include combinations with checkpoint inhibitors, radiation therapy, chemotherapy and several other existing cancer treatments. Importantly, FDA has approved PD-1 blockade agent to be used in combination with either CTLA-4 blockade or chemotherapy. Responsiveness to the PD-1 blockade therapy is affected by tumour and immune system-related factors. The role of the immune system, especially T cells, in determining the responsiveness has been poorly studied compared with those factors related to the tumour side. Energy metabolism has emerged as one of the important regulatory mechanisms for the function and differentiation of T cells. We have documented here the recent results regarding the augmentation of PD-1 blockade efficacy by augmenting mitochondrial energy metabolism of T cell.
Asunto(s)
Inmunoterapia/métodos , Neoplasias/terapia , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Animales , Antineoplásicos/uso terapéutico , Linfocitos B/inmunología , Terapia Combinada , Humanos , Neoplasias/tratamiento farmacológico , Neoplasias/radioterapia , Receptor de Muerte Celular Programada 1/inmunología , Linfocitos T/inmunologíaRESUMEN
Ischemic preconditioning (IPC) enhances whole-body exercise endurance. However, it is poorly understood whether the beneficial effects originate from systemic (e. g., cardiovascular system) or peripheral (e. g., skeletal muscle) adaptations. The present study examined the effects of IPC on local muscle endurance during fatiguing isometric exercise. 12 male subjects performed sustained isometric unilateral knee-extension exercise at 20% of maximal voluntary contraction until failure. Prior to the exercise, subjects completed IPC or control (CON) treatments. During exercise trial, electromyography activity and near-infrared spectroscopy-derived deoxygenation in skeletal muscle were continuously recorded. Endurance time to task failure was significantly longer in IPC than in CON (mean±SE; 233±9 vs. 198±9 s, P<0.001). Quadriceps electromyography activity was not significantly different between IPC and CON. In contrast, deoxygenation dynamics in the quadriceps vastus lateralis muscle was significantly faster in IPC than in CON (27.1±3.4 vs. 35.0±3.6 s, P<0.01). The present study found that IPC can enhance muscular endurance during fatiguing isometric exercise. Moreover, IPC accelerated muscle deoxygenation dynamics during the exercise. Therefore, we suggest that the origin of beneficial effects of IPC on exercise performance may be the enhanced mitochondrial metabolism in skeletal muscle.
Asunto(s)
Ejercicio Físico/fisiología , Precondicionamiento Isquémico , Resistencia Física/fisiología , Músculo Cuádriceps/fisiología , Electromiografía , Humanos , Contracción Isométrica , Rodilla , Masculino , Fatiga Muscular/fisiología , Oxígeno/fisiología , Consumo de Oxígeno , Adulto JovenRESUMEN
The alymphoplasia (aly) mutation of mouse is autosomal recessive and characterized by the systemic absence of lymph nodes (LN) and Peyer's patches (PP) and disorganized splenic and thymic structures with immunodeficiency. Although recent reports have shown that the interaction between lymphotoxin (LT) and the LT beta-receptor (Ltbeta r, encoded by Ltbr) provides a critical signal for LN genesis in mice, the aly locus on chromosome 11 is distinct from those for LT and its receptor. We found that the aly allele carries a point mutation causing an amino acid substitution in the carboxy-terminal interaction domain of Nf-kappa b-inducing kinase (Nik, encoded by the gene Nik). Transgenic complementation with wild-type Nik restored the normal structures of LN, PP, spleen and thymus, and the normal immune response in aly/aly mice. In addition, the aly mutation in a kinase domain-truncated Nik abolished its dominant-negative effect on Nf-kappa b activation induced by an excess of Ltbeta r. Our observations agree with previous reports that Ltbeta r-deficient mice showed defects in LN genesis and that Nik is a common mediator of Nf-kappa b activation by the tumour necrosis factor (TNF) receptor family. Nik is able to interact with members of the TRAF family (Traf1, 2, 3, 5 and 6), suggesting it acts downstream of TRAF-associating receptor signalling pathways, including Tnfr, Cd40, Cd30 and Ltbeta r. The phenotypes of aly/aly mice are more severe than those of Ltbr-/- mice, however, indicating involvement of Nik in signal transduction mediated by other receptors.
Asunto(s)
Ganglios Linfáticos/patología , Ganglios Linfáticos Agregados/patología , Proteínas Serina-Treonina Quinasas/genética , Secuencia de Aminoácidos , Animales , Línea Celular , ADN Complementario/química , ADN Complementario/genética , Humanos , Ganglios Linfáticos/enzimología , Receptor beta de Linfotoxina , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Datos de Secuencia Molecular , Ganglios Linfáticos Agregados/enzimología , Fenotipo , Mutación Puntual , Proteínas Serina-Treonina Quinasas/metabolismo , Receptores del Factor de Necrosis Tumoral/genética , Alineación de Secuencia , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Bazo/enzimología , Bazo/patología , Timo/enzimología , Timo/patología , Quinasa de Factor Nuclear kappa BRESUMEN
We have demonstrated quantum key distribution (QKD) over 100 km using single-photon detectors based on InGaAs/InP avalanche photodiodes (APDs). We implemented the differential phase shift QKD (DPS-QKD) protocol with electrically cooled and 2-GHz sinusoidally gated APDs. The single-photon detector has a dark count probability of 2.8 × 10(-8) (55 counts per second) with a detection efficiency of 6 %, which enabled us to achieve 24 kbit/s secure key rate over 100 km of optical fiber. The DPS-QKD system offers better performances in a practical way than those achieved using superconducting single-photon detectors. Moreover, the distance that secure keys against the general individual attacks can be distributed has been extended to 160 km.
RESUMEN
A secure communication network with quantum key distribution in a metropolitan area is reported. Six different QKD systems are integrated into a mesh-type network. GHz-clocked QKD links enable us to demonstrate the world-first secure TV conferencing over a distance of 45km. The network includes a commercial QKD product for long-term stable operation, and application interface to secure mobile phones. Detection of an eavesdropper, rerouting into a secure path, and key relay via trusted nodes are demonstrated in this network.
RESUMEN
PD-1 is an immunoglobulin superfamily member bearing an immunoreceptor tyrosine-based inhibitory motif, and disruption of the PD-1 gene results in the development of lupus-like autoimmune diseases. In this study, we examined effects of the PD-1 deficiency on the thymocyte differentiation at the clonal level using T cell receptor (TCR)-beta (Vbeta8) and TCR-alpha/beta (H-Y and 2C) transgenic mice. In these TCR transgenic lines, PD-1 expression in the thymus was variably augmented, but as in the normal mice, confined largely to the CD4(-)CD8(-) thymocytes. The transgenic mice crossed with PD-1(-/)- mice in the neutral genetic backgrounds exhibited selective increase in the CD4(+)CD8(+) (DP) population with little effect on other thymocytes subsets. Similarly, the absence of PD-1 facilitated expansion of DP thymocytes in recombination activating gene (RAG)-2(-/)- mice by anti-CD3epsilon antibody injection. On the other hand, H-Y or 2C transgenic PD-1(-/)- mice with the positively selecting background showed significantly reduced efficiency for the generation of CD8(+) single positive cells bearing the transgenic TCR-alpha/beta in spite of the increased DP population. These results collectively indicate that PD-1 negatively regulates the beta selection and modulates the positive selection, and suggest that PD-1 deficiency may lead to the significant alteration of mature T cell repertoire.
Asunto(s)
Reordenamiento Génico de la Cadena beta de los Receptores de Antígenos de los Linfocitos T , Inmunoglobulinas/inmunología , Receptores de Antígenos de Linfocitos T alfa-beta/genética , Timo/inmunología , Animales , Enfermedades Autoinmunes/etiología , Linfocitos T CD4-Positivos , Linfocitos T CD8-positivos , Proteínas de Unión al ADN/genética , Inmunoglobulinas/genética , Ratones , Ratones Noqueados , Ratones Transgénicos , Selección GenéticaRESUMEN
To test whether the product of the bcl-2 proto-oncogene blocks clonal deletion of self-reactive B cells, we have generated transgenic mice carrying the bcl-2 gene and the immunoglobulin genes for the anti-erythrocyte 4C8 antibody. In these transgenic mice, clonal deletion of self-reactive immature B cells in the bone marrow was not inhibited in spite of expression of the bcl-2 gene. In contrast, self-antigen-induced clonal deletion of mature self-reactive Ly-1 B (B1) cells in the peritoneal cavity was inhibited in the transgenic mice. These results indicate that the mechanism for clonal deletion of immature self-reactive B cells in the bone marrow differs from that of mature self-reactive B cells in the periphery.
Asunto(s)
Linfocitos B/citología , Células de la Médula Ósea , Proteínas Proto-Oncogénicas/fisiología , Animales , Antígenos Ly/inmunología , Apoptosis/inmunología , Autoanticuerpos/genética , Autoanticuerpos/inmunología , Enfermedades Autoinmunes/genética , Enfermedades Autoinmunes/inmunología , Enfermedades Autoinmunes/fisiopatología , Linfocitos B/inmunología , Secuencia de Bases , Médula Ósea/inmunología , Células Clonales , ADN , Eritrocitos/inmunología , Genes de Inmunoglobulinas , Tolerancia Inmunológica , Ratones , Ratones Transgénicos , Datos de Secuencia Molecular , Cavidad Peritoneal/citología , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas c-bcl-2RESUMEN
We analyzed the molecular mechanism for the immunoglobulin (Ig) multiple isotype expression using a transgenic mouse (TG.SA) model system. Though most of the endogenous mu chain expression was excluded by the expression of the human rearranged mu transgene in the TG.SA mouse, a significant portion of splenic B lymphocytes could express the transgenic human IgM and endogenous mouse IgG simultaneously after stimulation with lipopolysaccharide and interleukin 4. The fluorescence-activated cell sorter-purified population of the human IgM+/mouse IgG+ cells expressed mRNA that consisted of properly spliced sequences of the transgenic VHDJH and the endogenous mouse C gamma genes (trans-mRNA), together with the transgenic human mu mRNA and germline transcripts of the mouse C gamma gene, without apparent rearrangement of the transgene. We also found that a lymphoma tumor, derived from the cross between the TG.SA mouse and another transgenic mouse carrying Ig H chain enhancer-driven c-myc oncogene, expressed about equal levels of the trans-mRNA and the transgenic mu mRNA without DNA rearrangement in either the transgene or the endogenous mouse switch region. These findings strongly support our previous proposal that the trans-splicing can account for the multiple isotype expression in this transgenic model and also suggest that novel molecular mechanism(s) might be involved in this reaction.
Asunto(s)
Regulación de la Expresión Génica , Genes de Inmunoglobulinas , Cadenas Pesadas de Inmunoglobulina/genética , Isotipos de Inmunoglobulinas/genética , Empalme del ARN , Animales , Reordenamiento Génico de Cadena Pesada de Linfocito B , Humanos , Linfoma/genética , Ratones , Ratones Transgénicos , Reacción en Cadena de la Polimerasa , ARN Mensajero/genéticaRESUMEN
We have characterized extrachromosomal circular DNAs from adult mouse spleen cells that were induced to switch to immunoglobulin A (IgA) with bacterial lipopolysaccharide (LPS) and transforming growth factor beta (TGF-beta), and identified breakpoints of S mu/S gamma 3, S mu/S gamma 2, S mu/S alpha, S gamma 3/S alpha, and S gamma 2/S alpha recombinants. The S mu recombination donor sites clustered in the 3' half of the S mu region, while the S alpha recombination acceptor sites clustered in the 5' half of the S alpha region. In addition, donor and acceptor sites of S gamma regions also clustered in the 3' and 5' parts, respectively. These site preferences are in sharp contrast to the dispersed distribution of S mu/S gamma 1 breakpoints within both S mu and S gamma 1 regions upon IgG1 switch induced by LPS and interleukin 4. Our results support the hypotheses that TGF-beta increases the frequency of switch recombination events to IgA and that the switch recombination to IgA often proceeds by successive recombination of S mu/S gamma and S gamma/S alpha.
Asunto(s)
Genes de Cambio , Inmunoglobulina G/genética , Región de Cambio de la Inmunoglobulina , Recombinación Genética , Factor de Crecimiento Transformador beta/farmacología , Animales , Secuencia de Bases , Clonación Molecular , ADN Circular/genética , Femenino , Biblioteca de Genes , Genes de Cambio/efectos de los fármacos , Región de Cambio de la Inmunoglobulina/efectos de los fármacos , Interleucina-4/farmacología , Lipopolisacáridos , Ratones , Ratones Endogámicos BALB C , Modelos Genéticos , Datos de Secuencia Molecular , Oligodesoxirribonucleótidos , Plásmidos , Recombinación Genética/efectos de los fármacos , Mapeo Restrictivo , Bazo/inmunologíaRESUMEN
The complete nucleotide sequence of the 957-kb DNA of the human immunoglobulin heavy chain variable (VH) region locus was determined and 43 novel VH segments were identified. The region contains 123 VH segments classifiable into seven different families, of which 79 are pseudogenes. Of the 44 VH segments with an open reading frame, 39 are expressed as heavy chain proteins and 1 as mRNA, while the remaining 4 are not found in immunoglobulin cDNAs. Combinatorial diversity of VH region was calculated to be approximately 6,000. Conservation of the promoter and recombination signal sequences was observed to be higher in functional VH segments than in pseudogenes. Phylogenetic analysis of 114 VH segments clearly showed clustering of the VH segments of each family. However, an independent branch in the tree contained a single VH, V4-44.1P, sharing similar levels of homology to human VH families and to those of other vertebrates. Comparison between different copies of homologous units that appear repeatedly across the locus clearly demonstrates that dynamic DNA reorganization of the locus took place at least eight times between 133 and 10 million years ago. One nonimmunoglobulin gene of unknown function was identified in the intergenic region.
Asunto(s)
Genes de Inmunoglobulinas , Genoma Humano , Cadenas Pesadas de Inmunoglobulina/genética , Región Variable de Inmunoglobulina/genética , Cromosomas Artificiales de Levadura , Humanos , Filogenia , Análisis de Secuencia de ADNRESUMEN
An interleukin 3-dependent multipotential stem cell clone, LyD9, has been shown to generate mature B lymphocytes, macrophages, and neutrophils by coculture with primary bone marrow stromal cells. We report here that coculture with the cloned stromal cell lines PA6 and ST2 can support differentiation of LyD9 cells predominantly into granulocyte/macrophage colony-stimulating factor (GM-CSF)- and granulocyte (G)-CSF-responsive cells, respectively. However, these stromal cell lines were unable to support lymphopoiesis of LyD9 cells. The GM-CSF-dependent line, L-GM, which was derived from LyD9 cells cocultured with PA6 stromal cells, could differentiate into macrophages and granulocytes in the presence of GM-CSF. The L-GM line can further differentiate predominantly into neutrophils by coculture with ST2 stromal cells. The G-CSF-dependent line, L-G, which was derived from LyD9 cells cocultured with ST2 stromal cells, differentiated into neutrophils in response to G-CSF. Although the stromal cell-supported differentiation of LyD9 cells required the direct contact between LyD9 and stromal cells, a small fraction of LyD9 cells that were pretreated with 5-azacytidine could differentiate into neutrophils and macrophages without direct contact with stromal cells. These results indicate that different stromal cell lines support lineage-selective differentiation of the LyD9 stem cell and that 5-azacytidine treatment can bypass the requirement of direct contact with stromal cells, albeit with a lower frequency.
Asunto(s)
Células de la Médula Ósea , Células Madre Hematopoyéticas/citología , Animales , Azacitidina/farmacología , Linfocitos B/citología , Linfocitos B/efectos de los fármacos , Linfocitos B/fisiología , Médula Ósea/efectos de los fármacos , Médula Ósea/fisiología , Diferenciación Celular/fisiología , Línea Celular , Supervivencia Celular/efectos de los fármacos , Factor Estimulante de Colonias de Granulocitos/farmacología , Factor Estimulante de Colonias de Granulocitos y Macrófagos/farmacología , Células Madre Hematopoyéticas/efectos de los fármacos , Células Madre Hematopoyéticas/fisiología , Macrófagos/citología , Macrófagos/efectos de los fármacos , Macrófagos/fisiología , Ratones , Neutrófilos/citología , Neutrófilos/efectos de los fármacos , Neutrófilos/fisiologíaRESUMEN
We have analyzed expression patterns of 7 lymphokine mRNAs by Northern blot analyses in 19 different human T cell clones derived from patients with adult T cell leukemia. However, we were not able to reveal particular combinations of lymphokine production that allowed classification of human T cells. Especially, four clonally related leukemic lines that were established independently from the same patient with adult T cell leukemia expressed different combinations of lymphokine mRNAs, indicating that the expression of various lymphokines is not fixed but rather variable even among progenies of a single T cell clone.
Asunto(s)
Regulación de la Expresión Génica , Interleucinas/genética , Leucemia de Células T/metabolismo , Linfocitos T/metabolismo , Células Clonales , Sondas de ADN , Virus Linfotrópico T Tipo 1 Humano , Humanos , Interleucina-2/genética , Interleucina-4 , Interleucinas/biosíntesis , Hibridación de Ácido Nucleico , Poli A/análisis , ARN/análisis , ARN Mensajero/genética , Células Tumorales CultivadasRESUMEN
The IL-2-R is composed of at least two proteins, that is, a 55-kD protein (p55, the L chain, or Tac) and a 75-kD protein (p75, the H chain, or converter). The high affinity binding of IL-2 results in the formation of the ternary complex consisting of IL-2, and the L and H chains. To distinguish the affinity conversion model and the binary complex model we have carried out kinetic studies on the IL-2 binding to the high affinity IL-2-R on T lymphocytes expressing various numbers of L chains and a relatively constant number of H chains. We found that expression of a larger number of L chains accelerated the association of IL-2 to the high affinity receptor. The results are not compatible with the binary complex model that assumes a fixed number of high affinity sites determined by the numbers of a limiting chain. Instead, the results are consistent with the prediction of the affinity conversion model that assumes association of IL-2 to the L chain as the first step of the ternary complex formation and they indicate that the possible role of excess L chains is to accelerate the formation of the ternary complex. The reaction rate constants calculated from the affinity conversion model were reasonably constant.
Asunto(s)
Interleucina-2/metabolismo , Receptores de Interleucina-2/metabolismo , Humanos , Técnicas In Vitro , Cinética , Sustancias Macromoleculares , Relación Estructura-Actividad , Células Tumorales CultivadasRESUMEN
We made double transgenic mice bearing immunoglobulin heavy and light chain genes encoding an autoantibody against the mouse erythrocyte by the cross of C57BL/6 mice carrying the transgene for each chain of the immunoglobulin. Although no obvious disorders were found in the single-chain transgenic mice, severely anemic symptoms were found in some of the double transgenic mice, in which most B cells express, at least on their surface, the autoantibody reactive to self-antigens on the erythrocyte. Individual double-transgenic mice showed a wide variation of phenotypes between severe anemia and no symptoms. Both deletion and anergy of autoreactive B cells were seen in each individual mouse, but their relative contribution to self-tolerance was variable and not directly related to the severity of anemia or the amount of the autoantibody produced. This transgenic system provides a good autoimmune disease model for exploring its onset mechanism, and means of its treatment and prevention.
Asunto(s)
Anemia Hemolítica/genética , Autoanticuerpos/genética , Enfermedades Autoinmunes/genética , Linfocitos B/inmunología , Genes de Inmunoglobulinas , Cadenas Pesadas de Inmunoglobulina/genética , Cadenas Ligeras de Inmunoglobulina/genética , Anemia Hemolítica/inmunología , Animales , Anticuerpos Monoclonales , Formación de Anticuerpos , Enfermedades Autoinmunes/inmunología , Médula Ósea/inmunología , Cruzamientos Genéticos , Ensayo de Inmunoadsorción Enzimática , Eritrocitos/inmunología , Femenino , Citometría de Flujo , Técnica del Anticuerpo Fluorescente , Inmunoglobulina G/análisis , Inmunoglobulina G/genética , Ganglios Linfáticos/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Bazo/inmunologíaRESUMEN
Using cloned murine large granular lymphocyte (LGL) lines, the expression and the rearrangement of the alpha, beta, and gamma chain genes of the T cell receptor (TCR) were analyzed. Morphological, phenotypical, as well as functional studies indicated that the LGL lines were identical to normal, endogenous NK cells. Northern blot hybridization analysis indicated that the full-length transcripts of all the alpha, beta, and gamma chain genes were expressed in most of the LGL lines, including two lines derived from athymic nude mice. In one line, SPB, however, no transcript of the gamma chain gene was detected, whereas the alpha and beta chain genes were clearly expressed. In every LGL line studied, all of the alpha, beta, and gamma chain genes were rearranged. Conforming to the results of Northern blot hybridization study, the gamma chain gene of the SPB line was aberrantly rearranged, whereas those of all the other lines were productively rearranged. The results clearly revealed that NK cells represented a population of lymphocytes genetically committed to the T cell lineage. It was also suggested that the expression and rearrangement of the TCR genes of NK cells might occur in a thymus-independent fashion. An SPB line without expression of the gamma chain gene could exhibit NK activity indistinguishable from other NK lines. Furthermore, the rearrangement patterns of the beta chain gene did not correlate with the specificity of the cytotoxic activity. These results strongly suggested that the cytotoxic activity in NK cells was not directly mediated by TCR on them. We particularly noted that the beta chain gene of most independently established LGL lines showed identical patterns of rearrangement, indicating that they used the same V beta and J beta gene segments. The significance of the restricted pattern of rearrangement of the beta chain gene in LGL lines, as well as the possible functional roles of TCR on NK cells, was discussed.
Asunto(s)
Citotoxicidad Inmunológica , Células Asesinas Naturales/metabolismo , Receptores de Antígenos de Linfocitos T/genética , Recombinación Genética , Animales , Línea Celular , Células Clonales/metabolismo , Pruebas Inmunológicas de Citotoxicidad , ADN/metabolismo , Femenino , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/ultraestructura , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Hibridación de Ácido Nucleico , Transcripción GenéticaRESUMEN
The isotype specificity of immunoglobulin (Ig) class switching is regulated by a cytokine which induces transcription of a specific switch (S) region, giving rise to so-called germline transcripts. Although previous studies have demonstrated that germline transcription of an S region is required for class switch recombination (CSR) of that particular S region, it has not been shown whether the level of S region transcription affects the efficiency of CSR. We addressed this question by using an artificial DNA construct containing a constitutively transcribed mu switch (Smu) region and an alpha switch (Salpha) region driven by a tetracycline-responsive promoter. The construct was introduced into a switch-inducible B lymphoma line and the quantitative correlation between Salpha region transcription and class switching efficiency was evaluated. The level of Salpha transcription was linearly correlated with CSR efficiency, reaching a plateau at saturation. On the other hand, we failed to obtain the evidence to support involvement of either RNA-DNA heteroduplex or trans germline transcripts in CSR. Taken together, it is likely that S region transcription and/or transcript processing in situ may be required for CSR. We propose that because of the unusual properties of S region DNA, transcription induces the DNA to transiently be single stranded, permitting secondary structure(s) to form. Such structures may be recognition targets of a putative class switch recombinase.
Asunto(s)
Proteínas de Escherichia coli , Región de Cambio de la Inmunoglobulina/genética , Integrasas , Recombinación Genética , Acetilación , Animales , Secuencia de Bases , ADN/química , ADN/genética , ADN Nucleotidiltransferasas/metabolismo , Cartilla de ADN/genética , Proteínas de Unión al ADN/genética , Histonas/metabolismo , Linfoma de Células B/genética , Linfoma de Células B/inmunología , Linfoma de Células B/metabolismo , Ratones , Datos de Secuencia Molecular , Conformación de Ácido Nucleico , Recombinasas , Transfección , Células Tumorales CultivadasRESUMEN
The chromosomal location of the nu gene, which is responsible for hairlessness and athymus, was determined using six DNA markers (interleukin 3 [Il-3], Myhs, Acrb, Evi-2, Mpo, and Hox-2) on mouse chromosome 11. We constructed the high-resolution physical mapping of the six DNA markers on chromosome 11 by in situ hybridization using fluorescence-labeled cosmid probes. The results indicate the order of centromere-(41cM)-Il-3-(3cM)-Myhs- (4cM)-Acrb-(6cM)-Evi-2-(3cM)-Mpo-(5cM)- Hox-2. We have used congenic nude strains and examined which of the six DNA markers were derived from the original nude mouse. We found the Evi-2 locus is linked to the nu gene in all the informative, independent congenic nude strains. From these data, we could estimate the location of the nu gene, not only genetically but also physically within a region that spans approximately 17 megabases (9 cM) between the Acrb and Mpo genes.
Asunto(s)
Mapeo Cromosómico , Cromosomas Humanos Par 11 , ADN , Ratones Endogámicos/genética , Hibridación de Ácido Nucleico , Animales , Marcadores Genéticos/genética , Humanos , Interleucina-3/análisis , Interleucina-3/genética , Ratones , Ratones Endogámicos AKR , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Desnudos , Microscopía Fluorescente , Polimorfismo de Longitud del Fragmento de RestricciónRESUMEN
Using normal and transgenic (Tg) mice, we have shown that peritoneal B-1 cells are activated by administration of cytokines or lipopolysaccharide and migrate to other lymphoid organs where they differentiate into antibody-secreting cells. However, little is known about the process of B-1 cell migration and differentiation in vivo. We developed a mouse line by crossing the antierythrocyte antibody Tg mice (HL mice) with TCR-gamma/delta Tg mice specific for a self-thymus leukemia (TL) antigen in the recombination activating gene (RAG)2(-/-) background. In the presence of the self-antigen, Tg gamma/delta T cells increased in number and manifested activated phenotypes. Peritoneal B-1 cells in these mice migrated into mesenteric lymph nodes and differentiated into autoantibody-secreting cells, resulting in strong autoimmune hemolytic anemia. Furthermore, transfer of RAG2(-/-) x HL bone marrow or peritoneal cells into the peritoneal cavity of RAG2(-/-) x TCR-gamma/delta Tg mice gave rise to donor-derived B-1 cells in mesenteric lymph nodes, and these cells produced the autoantibody. Thus, this study demonstrates that the migration of B-1 cells and differentiation into the antibody-secreting cells can be induced by noncognate T cell help and implies the possibility that gamma/delta T cells may induce B-1 cell differentiation in vivo.
Asunto(s)
Autoanticuerpos/inmunología , Linfocitos B/fisiología , Movimiento Celular/fisiología , Eritrocitos/inmunología , Activación de Linfocitos/inmunología , Receptores de Antígenos de Linfocitos T gamma-delta/inmunología , Linfocitos T Colaboradores-Inductores/inmunología , Anemia/inmunología , Animales , Autoanticuerpos/biosíntesis , Linfocitos B/citología , Linfocitos B/inmunología , Células de la Médula Ósea/inmunología , Diferenciación Celular , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/inmunología , Femenino , Antígenos H-2/inmunología , Haplotipos , Cadenas Pesadas de Inmunoglobulina/inmunología , Cadenas Ligeras de Inmunoglobulina/inmunología , Inmunoglobulina M/inmunología , Inmunoglobulinas/inmunología , Antígenos Comunes de Leucocito/inmunología , Ganglios Linfáticos/inmunología , Masculino , Mesenterio , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Cavidad Peritoneal/citologíaRESUMEN
Surface-expressed immunoglobulin (Ig) has been shown to have a critical role in allelic exclusion of Ig heavy (H) and light (L) chains. Although various degrees of suppression of endogenous Ig expression are observed in Ig transgenic (Tg) mice, it was not clear whether this difference is due to different onsets of Tg expression or to different levels of Tg expression, which are obviously affected by integration sites of the transgene. In this study we generated antierythrocyte antibody Tg mice that carry tandem joined H and L chain transgenes (H+L) and confirmed that homozygosity of the transgene loci enhances the level of transgene expression as compared with heterozygosity. Suppression of endogenous H and L chain gene expression was stronger in homozygous than in heterozygous Tg mice. Similar results were obtained in control Tg mice carrying the H chain only. These results suggest that there is a threshold of the B cell receptor expression level that induces allelic exclusion. In addition, despite the same B cell receptor specificity, the size of Tg autoreactive B-1 cell compartment in the peritoneal cavity is larger in homozygous than in heterozygous mice, although the number of the Tg B-2 cell subset decreased in the spleen and bone marrow of homozygous Tg mice as compared with heterozygous Tg mice. By contrast, homozygosity of the H chain alone Tg line, which does not recognize self-antigens, did not increase the size of the peritoneal B-1 subset. These results suggest that the size of the B-1 cell subset in the Tg mice may depend on strength of signals through B cell receptors triggered by self-antigens.
Asunto(s)
Autoanticuerpos/biosíntesis , Subgrupos de Linfocitos B/inmunología , Linfocitos B/inmunología , Fragmentos de Inmunoglobulinas/genética , Receptores de Antígenos de Linfocitos B/biosíntesis , Receptores de Antígenos de Linfocitos B/genética , Alelos , Animales , Eritrocitos/inmunología , Heterocigoto , Homocigoto , Cadenas Pesadas de Inmunoglobulina/genética , Cadenas Ligeras de Inmunoglobulina/genética , Ratones , Ratones Transgénicos , TransgenesRESUMEN
In anti-red blood cell autoantibody transgenic (autoAb Tg) mice almost all B cells are deleted except for B-1 cells in the peritoneal cavity and the gut. About one-half of the auto Ab Tg mice suffer from autoimmune hemolytic anemia (AIHA) in the conventional condition. Oral administration of lipopolysaccharides activates B-1 cells and induces autoimmune symptoms in the Tg mice, suggesting that the autoimmune disease in anti-RBC autoAb Tg mice is triggered by infections. To examine the association of bacterial infections with the generation of B-1 cells and the occurrence of the autoimmune disease, we analyzed anti-RBC autoAb Tg mice bred in germ-free and specific pathogen-free conditions. In germ-free conditions, few peritoneal B-1 cells were detected, while a significant number of peritoneal B-1 cells existed in specific pathogen-free conditions. In both conditions, no mice suffered from AIHA. However, when these Tg mice were transferred to the conventional condition or injected with lipopolysaccharide, peritoneal B-1 cells expanded and some of these mice suffered from AIHA. These results clearly showed that bacterial infections are responsible for both the expansion of B-1 cells and the onset of the autoimmune disease in these Tg mice.