Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 23
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Dev Comp Immunol ; 57: 48-56, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26719025

RESUMO

The BTB-POZ transcription factor Promyelocytic Leukemia Zinc Finger (PLZF, or ZBTB16) has been recently identified as a major factor regulating the induction of a subset of Interferon stimulated genes in human and mouse. We show that the two co-orthologues of PLZF found in zebrafish show distinct expression patterns, especially in larvae. Although zbtb16a/plzfa and zbtb16b/plzfb are not modulated by IFN produced during viral infection, their over-expression increases the level of the early type I IFN response, at a critical phase in the race between the virus and the host response. The effect of Plzfb on IFN induction was also detectable after cell infection by different non-enveloped RNA viruses, but not after infection by the rhabdovirus SVCV. Our findings indicate that plzf implication in the regulation of type I IFN responses is conserved across vertebrates, but at multiple levels of the pathway and through different mechanisms.


Assuntos
Interferon Tipo I/imunologia , Fatores de Transcrição Kruppel-Like/metabolismo , Infecções por Vírus de RNA/imunologia , Vírus de RNA/imunologia , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/imunologia , Animais , Humanos , Imunidade Inata , Interferon Tipo I/metabolismo , Fatores de Transcrição Kruppel-Like/classificação , Fatores de Transcrição Kruppel-Like/genética , Camundongos , Filogenia , Poli I-C/imunologia , Proteína com Dedos de Zinco da Leucemia Promielocítica , RNA Viral/imunologia , Transcriptoma , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/classificação , Proteínas de Peixe-Zebra/genética
2.
Genes Immun ; 15(5): 293-302, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24833303

RESUMO

The class II cytokine family consists of small α-helical signaling proteins including the interleukin-10 (IL-10)/IL-22 family, as well as interferons (IFNs). They regulate the innate immune response and in addition have an important role in protecting epithelial tissues. Teleost fish possess a class II cytokine system surprisingly similar to that of humans, and thus zebrafish offers an attractive model organism for investigating the role of class II cytokines in inflammation. However, the evolution of class II cytokines is critical to understand if we are to take full advantage of zebrafish as a model system. The small size and fast evolution of these cytokines obscure phylogenetic analyses based purely on sequences, but one can overcome this obstacle by using information contained within the structure of those molecules. Here we present the crystal structure of IL-22 from zebrafish (zIL-22) solved at 2.1 Å, which displays a typical class II cytokine architecture. We generated a structure-guided alignment of vertebrate class II cytokines and used it for phylogenetic analysis. Our analysis suggests that IL-22 and IL-26 arose early during the evolution of the IL-10-like cytokines. Thus, we propose an evolutionary scenario of class II cytokines in vertebrates, based on genomic and structural data.


Assuntos
Sequência Conservada , Evolução Molecular , Interleucinas/química , Sequência de Aminoácidos , Animais , Cristalografia por Raios X , Humanos , Interleucinas/genética , Dados de Sequência Molecular , Peixe-Zebra , Interleucina 22
3.
J Virol ; 87(18): 10025-36, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23824820

RESUMO

ISG15, a 15-kDa interferon-induced protein that participates in antiviral defenses of mammals, is highly conserved among vertebrates. In fish, as in mammals, viral infection and interferon treatment induce isg15 expression. The two ubiquitin-like domains of ISG15 and the presence of a consensus LRLRGG sequence in the C-terminal region, which is required for the covalent conjugation to a substrate protein, are also conserved in fish. Our data demonstrate that overexpression of zebrafish ISG15 (zf-ISG15) in EPC cells is sufficient to inhibit viral infection by RNA viruses belonging to the genera Novirhabdovirus and Birnavirus and by DNA viruses of the genus Iridovirus. In coexpression experiments with IHNV proteins, we demonstrate specific ISGylation of phosphoprotein and nonvirion protein. Mutation of the glycine residues in the consensus LRLRGG motif abolishes zf-ISG15 conjugation to these proteins and the cellular protection against viral infection, thus connecting ISGylation and ISG15-dependent viral restriction. Additionally, zf-ISG15 overexpression triggers induction of the rig-I and viperin genes as well as, to a lesser extent, the IFN gene. Overall, our data demonstrate the antiviral effect of a fish ISG15 protein, revealing the conservation among vertebrates of an ISGylation mechanism likely directed against viruses. Furthermore, our findings indicate that zf-ISG15 affects the IFN system at several levels, and its study shall shed further light on the evolution of the complex regulation of the innate antiviral response in vertebrate cells.


Assuntos
Vírus de DNA/imunologia , Interferons/imunologia , Vírus de RNA/imunologia , Ubiquitina/imunologia , Proteínas Virais/metabolismo , Peixe-Zebra/imunologia , Animais , Linhagem Celular , Interferons/biossíntese , Dados de Sequência Molecular , Ligação Proteica , Processamento de Proteína Pós-Traducional , Análise de Sequência de DNA , Ubiquitina/genética , Peixe-Zebra/genética , Peixe-Zebra/virologia
5.
J Immunol ; 163(6): 3076-82, 1999 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-10477572

RESUMO

IL-4-producing gamma delta thymocytes in normal mice belong to a distinct subset of gamma delta T cells characterized by low expression of Thy-1. This gamma delta thymocyte subset shares a number of phenotypic and functional properties with the NK T cell population. Thy-1dull gamma delta thymocytes in DBA/2 mice express a restricted repertoire of TCRs that are composed of the V gamma 1 gene product mainly associated with the V delta 6.4 chain and exhibit limited junctional sequence diversity. Using mice transgenic for a rearranged V gamma 1J gamma 4C gamma 4 chain and a novel mAb (9D3) specific for the V delta 6.3 and V delta 6.4 murine TCR delta chains, we have analyzed the peripheral localization and functional properties of gamma delta T cells displaying a similarly restricted TCR repertoire. In transgenic mice, IL-4 production by peripheral gamma delta T cells was confined to the gamma delta+9D3+ subset, which contains cells with a TCR repertoire similar to that found in Thy-1dull gamma delta thymocytes. In normal DBA/2 mice such cells represent close to half of the gamma delta T cells present in the liver and around 20% of the splenic gamma delta T cells.


Assuntos
Interleucina-4/biossíntese , Fígado/imunologia , Fígado/metabolismo , Receptores de Antígenos de Linfócitos T gama-delta/biossíntese , Baço/imunologia , Baço/metabolismo , Subpopulações de Linfócitos T/metabolismo , Animais , Anticorpos Monoclonais/metabolismo , Anticorpos Monoclonais/farmacologia , Movimento Celular/imunologia , Feminino , Imunofenotipagem , Interferon gama/biossíntese , Interleucina-2/farmacologia , Fígado/citologia , Ativação Linfocitária/imunologia , Contagem de Linfócitos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Camundongos Knockout , Camundongos Transgênicos , Especificidade de Órgãos/imunologia , Receptores de Antígenos de Linfócitos T gama-delta/genética , Receptores de Antígenos de Linfócitos T gama-delta/imunologia , Receptores de Antígenos de Linfócitos T gama-delta/metabolismo , Baço/citologia , Subpopulações de Linfócitos T/citologia
6.
FASEB J ; 13(12): 1627-36, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10463955

RESUMO

The effects of the glycoinositolphospholipids (GIPLs) fromTrypanosoma cruzi on T lymphocyte activation were investigated in a mouse T cell hybridoma (DO-11.10). Purified GIPLs from T. cruzi strains Y and G markedly increased IL-2 mRNA transcripts and IL-2 secretion induced by mitogenic anti-CD3 and anti-Thy1 mAbs. This costimulatory function was also revealed by the induction of IL-2 secretion after the simultaneous addition of the T. cruzi GIPLs and either the calcium ionophore A23187 or phorbol ester. The capacity of the GIPL molecule to induce an increase in cytoplasmic calcium levels was also demonstrated. After exposure of T cell hybridoma to GIPL, the nuclear transcription factor NFAT1 became partially dephosphorylated, and its nuclear localization was demonstrated both in the T cell hybridoma and in Balb/c CD3(+) cells. These results demonstrate that T. cruzi GIPL molecules are capable of signaling to T cells and therefore could be valuable tools for the study of T cell activation, besides playing a potential role in subverting the T lymphocyte immune response during T. cruzi infection.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Glicolipídeos/imunologia , Interleucina-2/genética , Ativação Linfocitária , Proteínas Nucleares , Fosfolipídeos/imunologia , Linfócitos T/fisiologia , Fatores de Transcrição/metabolismo , Transcrição Gênica/imunologia , Trypanosoma cruzi/imunologia , Animais , Anticorpos Monoclonais/farmacologia , Complexo CD3/imunologia , Calcimicina/farmacologia , Linhagem Celular , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/fisiologia , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/imunologia , Glicolipídeos/isolamento & purificação , Glicolipídeos/farmacologia , Hibridomas/efeitos dos fármacos , Hibridomas/imunologia , Hibridomas/fisiologia , Interleucina-2/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Fatores de Transcrição NFATC , Fosfolipídeos/isolamento & purificação , Fosfolipídeos/farmacologia , Fosforilação , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Células Th1/imunologia , Transcrição Gênica/efeitos dos fármacos
7.
J Exp Med ; 189(10): 1591-600, 1999 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-10330438

RESUMO

Primary T cell responses rely on the recruitment and proliferation of antigen-specific T cell precursors. The extent of expansion of each individual T cell clone may depend on (a) its frequency before immunization, (b) its proliferative capacity, and (c) the time at which it first encounters its cognate antigen. In this report, we have analyzed the relative contribution of each of these parameters to the shaping of immune repertoires in the T cell response specific for the epitope 170-179 derived from HLA-Cw3 and presented by Kd. By means of hemisplenectomy, we compared immune and naive repertoires in the same animal and found that the frequency of all expanded T cell clones was extremely low before immunization. In particular, the most expanded clones did not derive from high-frequency precursors. In addition, recruited T cells were found to proliferate at the same rate, irrespective of their T cell antigen receptor sequence. Finally, we showed that only T cells that encounter the antigen at early time points account for a significant part of the specific response. Therefore, the contribution of a T cell clone to the immune response is mostly determined by the time of its entry into the immune repertoire, i.e., the time of first cell division after antigen encounter.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Animais , Linfócitos T CD8-Positivos/metabolismo , Divisão Celular , Células Clonais/imunologia , Células Clonais/metabolismo , Clonagem Molecular , Genes Codificadores da Cadeia beta de Receptores de Linfócitos T/imunologia , Antígenos de Histocompatibilidade/imunologia , Imunização , Masculino , Camundongos , Camundongos Endogâmicos DBA , Fragmentos de Peptídeos/imunologia , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/imunologia , Baço/imunologia , Fatores de Tempo
8.
J Virol ; 73(5): 3709-17, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10196263

RESUMO

During the late phase of adult T-cell leukemia/lymphoma, a severe lymphoproliferative disorder caused by human T-cell leukemia virus type 1 (HTLV-1), leukemic cells no longer produce interleukin-2. Several studies have reported the lack of the Src-like protein tyrosine kinase Lck and overexpression of Lyn and Fyn in these cells. In this report we demonstrate that, in addition to the downregulation of TCR, CD45, and Lck (which are key components of T-cell activation), HTLV-1-infected cell lines demonstrate a large increase of FynB, a Fyn isoform usually poorly expressed in T cells. Furthermore, similar to anergic T cells, Fyn is hyperactive in one of these HTLV-1-infected T-cell lines, probably as a consequence of Csk downregulation. A second family of two proteins, Zap-70 and Syk, relay the signal of T-cell activation. We demonstrate that in contrast to uninfected T cells, Zap-70 is absent in HTLV-1-infected T cells, whereas Syk is overexpressed. In searching for the mechanism responsible for FynB overexpression and Zap-70 downregulation, we have investigated the ability of the Tax and Rex proteins to modulate Zap-70 expression and the alternative splicing mechanism which gives rise to either FynB or FynT. By using Jurkat T cells stably transfected with the tax and rex genes or inducibly expressing the tax gene, we found that the expression of Rex was necessary to increase fynB expression, suggesting that Rex controls fyn gene splicing. Conversely, with the same Jurkat clones, we found that the expression of Tax but not Rex could downregulate Zap-70 expression. These results suggest that the effect of Tax and Rex must cooperate to deregulate the pathway of T-cell activation in HTLV-1-infected T cells.


Assuntos
Vírus Linfotrópico T Tipo 1 Humano/fisiologia , Receptores Proteína Tirosina Quinases/biossíntese , Quinases da Família src/biossíntese , Regulação para Baixo , Humanos , Interleucina-2/metabolismo , Células Jurkat , Antígenos Comuns de Leucócito/biossíntese , Proteína Tirosina Quinase p56(lck) Linfócito-Específica/biossíntese , Fosforilação , Proteína Tirosina Fosfatase não Receptora Tipo 1 , Proteínas Tirosina Quinases/biossíntese , Proteínas Proto-Oncogênicas/biossíntese , Proteínas Proto-Oncogênicas c-fyn , Receptores de Antígenos de Linfócitos T/biossíntese , Células Tumorais Cultivadas , Proteína-Tirosina Quinase ZAP-70
9.
J Immunol ; 162(1): 609-17, 1999 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-9886439

RESUMO

Cancer immunotherapy often aims at the reactivation and expansion of tumor-specific CTL. In an attempt to correlate in situ and/or systemic tumor-specific T cell expansion with tumor regression, we investigated the effects of adenovirus-mediated IL-12 or IFN-gamma gene transfer into established P815 murine tumors. While IFN-gamma was no more potent than the vector alone, IL-12 gene transfer promoted tumor eradication. Despite this antitumor effect, no significant cytolytic activity was detectable using classical cytotoxicity assays from in vitro restimulated splenocytes. Since intratumor gene delivery may induce a localized expansion of CTL, the presence of P815-specific CD8+ T cells in situ was assessed. Using the Immunoscope approach, we found a dramatic increase in clonotypic T cells at the tumor site following IL-12, but not IFN-gamma gene delivery. Antitumor CD8+ T cell frequencies were then re-evaluated using this molecular detection technique, which revealed a comparable expansion of specific T cells in the peripheral organs, most strikingly in the blood. These data show that local IL-12 gene transfer, in contrast to IFN-gamma, mediates a potent antitumor effect that correlates to clonal tumor-specific T cell expansions in situ and in the periphery.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Epitopos de Linfócito T/sangue , Terapia Genética , Interleucina-12/genética , Sarcoma de Mastócitos/terapia , Sarcoma Experimental/terapia , Subpopulações de Linfócitos T/imunologia , Adenoviridae/genética , Animais , Linfócitos T CD8-Positivos/metabolismo , Movimento Celular/genética , Movimento Celular/imunologia , Citotoxicidade Imunológica/genética , Feminino , Terapia Genética/métodos , Vetores Genéticos/administração & dosagem , Vetores Genéticos/uso terapêutico , Injeções Intravenosas , Interferon gama/biossíntese , Interleucina-12/metabolismo , Interleucina-12/uso terapêutico , Contagem de Linfócitos , Sarcoma de Mastócitos/sangue , Sarcoma de Mastócitos/genética , Sarcoma de Mastócitos/imunologia , Camundongos , Camundongos Endogâmicos DBA , Recombinação Genética , Sarcoma Experimental/sangue , Sarcoma Experimental/genética , Sarcoma Experimental/imunologia , Subpopulações de Linfócitos T/metabolismo , Fatores de Tempo
10.
J Immunother ; 21(4): 283-94, 1998 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9672850

RESUMO

We have previously described the production and purification of a murine single-chain, soluble recombinant major histocompatibility complex (MHC) class I molecule (SC-Kd). A similar strategy was devised to produce a recombinant HLA-A2.1 (SC-A2) molecule. The latter was composed of the first three domains of the HLA-A2.1 heavy chain connected to human beta 2-microglobulin through a spacer of 15 amino acids. Immunoaffinity-purified SC-A2 molecules-were correctly folded and biologically functional. They specifically bound HLA-A2-restricted peptides and induced a peptide-specific cytotoxic T lymphocyte (CTL) clone to proliferate and secrete interleukin-2. The ability of murine and human SC-MHC molecules to elicit primary CTLs in vitro was next investigated. When coated in high density onto beads, complexes of antigenic peptide and SC-Kd or SC-A2 molecules efficiently induced a specific primary CTL response in vitro. Furthermore, the structural features of these CTLs were characterized by T cell receptor-beta chain analysis, which revealed rearrangements very similar, if not identical, to those found in CTLs generated by in vivo immunization. Such single-chain, soluble recombinant MHC class I molecules should provide a useful tool in particular for peptide binding assays and for in vitro primary CTL induction to identify immunogenic peptides such as those derived from known tumor-associated antigens.


Assuntos
Antígeno HLA-A2/imunologia , Linfócitos T Citotóxicos/imunologia , Animais , Células Cultivadas , Rearranjo Gênico do Linfócito T , Antígeno HLA-A2/química , Humanos , Masculino , Camundongos , Camundongos Endogâmicos DBA , Ratos , Proteínas Recombinantes/imunologia
11.
Res Immunol ; 149(2): 119-25, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9628393

RESUMO

Technological advances in the field of nucleic acid analysis were the object of a recent meeting held in Lisbon. This report presents those techniques that may be most useful for immunologists as well as some of their potential applications. The topics covered include automation, quantitative PCR and its alternatives, oligonucleotide chips, and in situ hybridization and PCR.


Assuntos
Alergia e Imunologia , DNA/análise , Técnicas Genéticas , RNA/análise , Automação , DNA/isolamento & purificação , Eletroforese , Técnicas Genéticas/instrumentação , Hibridização In Situ , Reação em Cadeia da Polimerase , RNA/isolamento & purificação , Análise de Sequência de DNA
12.
J Immunol ; 158(7): 3335-43, 1997 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-9120291

RESUMO

Regression of P815 tumors established on naive syngeneic mice can be obtained by the intratumoral injection of a single dose of an adenoviral vector expressing the IL-2 gene (Ad.IL2). Injection triggers local IL-2 production for at least 10 days. We measured a number of immunologic parameters in situ following intratumoral Ad.IL2 treatment. We also analyzed the situation of regression obtained upon challenge with P815 cells of mice previously immunized against the tumor and compared both systems. While IFN-gamma messenger RNA expression was found to be elevated in both situations of tumor regression, the level of infiltration by tumor-specific CTL was different. A small amount of tumor-specific CD8+ T cells were present in growing, untreated tumors. Such cells are found in much larger numbers in tumors rejected upon challenge, consistent with a CTL-mediated rejection. In contrast, they were found not to proliferate following Ad.IL2 injection. The latter caused an increased infiltration of a polyclonal, presumably nonspecific, T cell population. These results suggest that the initial regression of established P815 tumors following Ad.IL2 treatment in vivo is mostly due to nonspecific effectors.


Assuntos
Técnicas de Transferência de Genes , Interleucina-2/genética , Ativação Linfocitária/genética , Sarcoma de Mastócitos/imunologia , Sarcoma de Mastócitos/terapia , Linfócitos T Citotóxicos/imunologia , Animais , Feminino , Rejeição de Enxerto/genética , Rejeição de Enxerto/imunologia , Interferon gama/biossíntese , Interferon gama/genética , Interleucina-2/administração & dosagem , Sarcoma de Mastócitos/genética , Camundongos , Camundongos Endogâmicos DBA , Transplante de Neoplasias , RNA Mensageiro/biossíntese , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Linfócitos T Citotóxicos/metabolismo
13.
Eur J Immunol ; 27(2): 544-53, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9045929

RESUMO

We have characterized the function, phenotype, ontogenic development, and T cell receptor (TCR) repertoire of a subpopulation of gamma delta thymocytes, initially defined by expressing low levels of Thy-1, that represents around 5% and 30% of total gamma delta thymocytes in adult C57BL/6 and DBA/2 mice, respectively. Activation of FACS-sorted Thy-1dull gamma delta thymocytes from DBA/2 mice with anti-gamma delta monoclonal antibodies in the presence of interleukin-2 (IL-2) results in the secretion of high levels of several cytokines, including interferon-gamma (IFN-gamma), IL-4, IL-10, and IL-3. In contrast, only IFN-gamma was detected in parallel cultures of Thy-1bright gamma delta thymocytes. Virtually all Thy-1dull gamma delta thymocytes express high levels of CD44 and low levels of the heat-stable antigen and CD62 ligand, while around half of them express the NK1.1 marker. Thy-1dull gamma delta thymocytes are barely detectable in newborn animals, and their representation increases considerably during the first 2 weeks of postnatal life. The majority of Thy-1dull gamma delta thymocytes from DBA/2 mice express TCR encoded by the V gamma 1 gene and a novel V delta 6 gene named V delta 6.4. Sequence analysis of these functionally rearranged gamma and delta genes revealed highly restricted V delta-D delta-J delta junctions, and somewhat more diverse V gamma-J gamma junctions. We conclude that Thy-1dull gamma delta thymocytes exhibit properties that are equivalent to those of natural killer TCR alpha beta T cells. Both cell populations produce the same distinct pattern of cytokines upon activation, share a number of phenotypic markers originally defined for activated or memory T cells, display similar postnatal kinetics of appearance in the thymus and express a very restricted TCR repertoire.


Assuntos
Citocinas/biossíntese , Receptores de Antígenos de Linfócitos T gama-delta/análise , Receptores de Antígenos de Linfócitos T/biossíntese , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Timo/citologia , Timo/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Citocinas/metabolismo , Feminino , Hibridomas , Interleucina-10/biossíntese , Interleucina-3/biossíntese , Interleucina-4/biossíntese , Células Matadoras Naturais/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Dados de Sequência Molecular , Receptores de Antígenos de Linfócitos T alfa-beta/biossíntese , Antígenos Thy-1/análise , Antígenos Thy-1/biossíntese , Antígenos Thy-1/fisiologia
14.
Eur J Immunol ; 26(4): 914-21, 1996 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8625988

RESUMO

In conventional mice, the T cell receptor (TCR) alpha beta+ CD8 alpha alpha+ and CD8 alpha beta+ subsets of the intestinal intraepithelial lymphocytes (IEL) constitute two subpopulations. Each comprise a few hundred clones expressing apparently random receptor repertoires which are different in individual genetically identical mice (Regnault, A., Cumano, A., Vassalli, P., Guy-Grand, D. and Kourilsky, P., J. Ep. Med. 1994. 180: 1345). We analyzed the repertoire diversity of sorted CD8 alpha alpha and CD8 alpha beta TCR alpha beta+ IEL populations from the small intestine of individual germ-free mice that contain ten times less TCR alpha beta+ T cells than conventional mice. The TCR beta repertoire of the CD8 alpha alpha and the CD8 alpha beta IEL populations of germ-free adult mice shows the same degree of oligoclonality as that of conventional mice. These results show the intestinal microflora is not responsible for the repertoire oligoclonality of TCR alpha beta+ IEL. The presence of the microflora leads to an expansion of clones which arise independently of bacteria. To evaluate the degree of expansion of IEL clones in conventional mice, we went on to measure their clone sizes in vivo by quantitative PCR in the total and in adjacent sections of the small intestine of adult animals. We found that both the CD8 alpha alpha and the CD8 alpha beta TCR alpha beta IEL clones have a heterogeneous size pattern, with clones containing from 3 x 10(3) cells up to 1.2 x 10(6) cells, the clones being qualitatively and quantitatively different in individual mice. Cells from a given IEL clone are not evenly distributed throughout the length of the small intestine. The observation that the TCR alpha beta IEL populations comprise a few hundred clones of very heterogeneous size and distribution suggests that they arise from a limited number of precursors, which may be slowly but continuously renewed, and undergo extensive clonal expansion in the epithelium.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Rearranjo Gênico da Cadeia beta dos Receptores de Antígenos dos Linfócitos T , Mucosa Intestinal/citologia , Receptores de Antígenos de Linfócitos T alfa-beta , Subpopulações de Linfócitos T/imunologia , Animais , Sequência de Bases , Divisão Celular , Células Clonais , Células Epiteliais , Mucosa Intestinal/imunologia , Mucosa Intestinal/microbiologia , Contagem de Linfócitos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos DBA , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , RNA Mensageiro/análise
15.
J Exp Med ; 183(2): 439-49, 1996 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-8627157

RESUMO

P815 is a murine mastocytoma of DBA/2 origin which, although immunogenic, rapidly develops as a tumor in immunocompetent syngeneic hosts. In this report, we have studied, by a molecular approach, the in vivo alpha/beta T cell response to P815. Both situations of tumor growth after engraftment of naive animals or tumor rejection by preimmunized animals have been analyzed. The spectrum of T cell receptor beta chain rearrangements in the tumor-infiltrating lymphocytes was found to be highly variable among individual tumor-bearing mice. However, two rearrangements, one using V(beta)1 and J(beta)1.2 segments and one using the V(beta)1 and J(beta)2.5 segments, with conserved junctional regions, reproducibly emerge in most individuals. These two rearrangements thus correspond to "public" (recurrent) T cell clones, as opposed to "private" ones, which emerge in a seemingly stochastic fashion in immunized animals. Importantly, these public cells are observed in situations of either growth or rejection of the tumor. Quantification provides a clear increase in public T cells in secondary responses, but no obvious correlation provides between their level and primary tumor rejection. The V(beta)1- J(beta)1.2 rearrangement is borne by CTL directed against an antigen derived from P1A, a nonmutated mouse self protein which is expressed in P815 but not in normal mouse tissues except testis. A recurrent, public T cell response can thus be observed to an antigen derived from a self protein expressed by a tumor.


Assuntos
Rearranjo Gênico da Cadeia beta dos Receptores de Antígenos dos Linfócitos T , Sarcoma de Mastócitos/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Sarcoma Experimental/imunologia , Linfócitos T Citotóxicos/imunologia , Sequência de Aminoácidos , Animais , Antígenos de Neoplasias/imunologia , Sequência de Bases , Células Clonais/imunologia , Feminino , Rejeição de Enxerto , Linfócitos do Interstício Tumoral/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Análise de Sequência de DNA
16.
Int Immunol ; 6(11): 1759-66, 1994 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-7865468

RESUMO

MHC class I molecules bind short peptides derived from endogenously synthesized proteins. This binding occurs at neutral pH and MHC class I-peptide complexes dissociate at low or high pH. Here we show that MHC class I-peptide complexes expressed at the cell surface dissociate upon a brief and mild acid treatment without affecting cell viability or capacity of the peptide-stripped MHC molecules to re-bind exogenous peptides. Mouse or human blasts that have been peptide-stripped and reloaded with an exogenous peptide can induce in vitro peptide specific primary cytotoxic T lymphocytes (CTL) in mixed lymphocyte cultures. Mice immunized with syngeneic blasts that have been peptide-stripped and reloaded with a peptide derived from a tumor-associated antigen are protected against a subsequent challenge with a lethal dose of tumor cells. The importance of these findings for viral and tumor immunotherapy as well as for unravelling the mechanisms of induction of primary CTL responses are discussed.


Assuntos
Antígenos H-2/imunologia , Peptídeos/imunologia , Linfócitos T Citotóxicos/imunologia , Sequência de Aminoácidos , Animais , Células Apresentadoras de Antígenos/imunologia , Linhagem Celular , Testes Imunológicos de Citotoxicidade , Antígenos H-2/química , Humanos , Hibridomas/imunologia , Teste de Cultura Mista de Linfócitos , Camundongos , Dados de Sequência Molecular , Peptídeos/síntese química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...