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1.
BMC Pediatr ; 20(1): 272, 2020 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-32493258

RESUMO

BACKGROUND: Congenital malformations are described in about 3% of live births and 20% of stillbirths in the industrialized countries. The prevalence of congenital anomalies in developing countries, including Morocco, is not well known at the national level. The aim of our study is to conduct a descriptive exploratory analysis of congenital malformations cases diagnosed at the "Les Orangers" Maternity and Reproductive Health Hospital in Rabat. METHODS: We collected all the cases of congenital malformations diagnosed at the "Les Orangers" Maternity and Reproductive Health Hospital in Rabat, from January 1st, 2011 to June 31st, 2016. Data were reported on pre-established sheets and on a registry of malformations. Total and specific prevalences were calculated for each malformation. A principal component analysis (PCA) was then conducted followed by a Varimax rotation in order to identify the different associations of malformations in our series. RESULTS: We registred 245 cases of congenital malformations out of a total of 43,923 recorded births; a prevalence of 5.58 per thousand births of which 19.2% were FDIU (fetal deaths in utero). A polymalformative syndrome was found in 26.5% of cases which makes a total number of 470 anomalies. The musculoskeletal anomalies predominate with a rate of 33%, followed by neurological abnormalities 18%, of whom 31% were hydrocephalus, 26.2% anencephaly, and 20.24% spina bifida. Malformations of the eye, ear, face and neck were described in 12% of the cases, while genetic abnormalities were observed in 8,5% of which 87.5% represented Down syndrome. The antenatal diagnosis of congenital malformations was performed in 28.6% of cases. CONCLUSIONS: Our study provides a general overview of the epidemiological situation related to different types of congenital anomalies for a specific area in Morocco. It represents a database that should be complemented by other multicenter studies and the implementation of a national registry to determine the prevalence of congenital malformations at a national level.


Assuntos
Anormalidades Congênitas , Saúde Reprodutiva , Anormalidades Congênitas/epidemiologia , Feminino , Hospitais , Humanos , Marrocos , Gravidez , Diagnóstico Pré-Natal , Prevalência
2.
J Exp Med ; 160(4): 1070-86, 1984 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-6207261

RESUMO

The primary structure of A/J anti-p-azophenylarsonate (anti-Ars) antibodies expressing the major A-strain cross-reactive idiotype (CRIA) has provided important insights into issues of antibody diversity and the molecular basis of idiotypy in this important model system. Until recently, this idiotype was thought to be rarely, if ever, expressed in BALB/c mice. Indeed, it has been reported that BALB/c mice lack the heavy chain variable segment (VH) gene that is utilized by the entire family of anti-Ars antibodies expressing the A/J CRI. Recently, however, it has been possible to elicit CRIA+, Ars binding antibodies in the BALB/c strain by immunizing first with anti-CRI and then with antigen. Such BALB/c, CRIA+ anti-Ars antibodies can be induced occasionally with antigen alone. VH region amino acid sequences are described for two CRIA+ hybridoma products derived from BALB/c mice. While remarkably similar to each other, their VH segments (1-98) differ from the VH segments of A/J CRIA+, anti-Ars antibodies in over 40 positions. Rather than the usual JH2 gene segment used by most A/J CRIA+ anti-Ars antibodies, one BALB/c CRIA+ hybridoma utilizes a JH1 gene segment, while the other uses a JH4. However, the D segments of both of the BALB/c antibodies are remarkably homologous to the D segments of several A/J CRIA+ antibodies sequenced previously, as are the amino terminal amino acid sequences of their light chains. These data imply that BALB/c mice express the A/J CRIA by producing antibodies with very similar, if not identical, light chain and heavy chain D segments, but in the context of different VH and JH gene segments than their A/J counterparts. The results document that molecules that share serologic specificities can have vastly different primary structures.


Assuntos
Anticorpos Monoclonais/análise , Compostos Azo/imunologia , Cadeias Pesadas de Imunoglobulinas/análise , Idiótipos de Imunoglobulinas/imunologia , Região Variável de Imunoglobulina/análise , p-Azobenzenoarsonato/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Anti-Idiotípicos/análise , Anticorpos Anti-Idiotípicos/genética , Anticorpos Monoclonais/classificação , Anticorpos Monoclonais/genética , Diversidade de Anticorpos , Linfócitos B/imunologia , Sítios de Ligação de Anticorpos , Reações Cruzadas , Epitopos/imunologia , Cadeias Pesadas de Imunoglobulinas/genética , Idiótipos de Imunoglobulinas/classificação , Idiótipos de Imunoglobulinas/genética , Cadeias Leves de Imunoglobulina/análise , Cadeias Leves de Imunoglobulina/genética , Região Variável de Imunoglobulina/genética , Camundongos , Camundongos Endogâmicos A , Camundongos Endogâmicos BALB C , Coelhos
3.
J Exp Med ; 160(1): 1-11, 1984 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-6610720

RESUMO

We have shown that, by suitable idiotypic manipulation, BALB/c mice can express the major cross-reactive idiotype (CRI) of A/J mice in response to azophenylarsonate (Ars). In order to know if the CRIA idiotype is present in the potential repertoire of BALB/c before any intentional selection, we used polyclonal activation in vitro and limiting dilution analysis. The readout was done with two monoclonal anti-CRIA antibodies that recognize distinct idiotopes on a CRIA+ A/J germline-encoded monoclonal antibody. We studied the frequency of CRIA+ lipopolysaccharide (LPS)-reactive cells in the spleens of nonimmune and immune A/J mice and in the spleens of naive and manipulated (i.e., producing CRIA+ antibodies) BALB/c mice. A/J and BALB/c naive individuals presented very high frequencies of Ars-specific B cells while the frequency of CRIA+ B cells was only a minor subset (0.5%) of the total Ars-specific subset in the two strains. When A/J mice were immunized with Ars-keyhole limpet hemocyanin, a clear preferential expansion of the CRIA+ minor subset of A/J mice was observed (100x). No such enhancement was observed in BALB/c mice similarly treated. Manipulated BALB/c mice presented a higher frequency of CRIA+ anti-Ars B cells than naive or antigen-immunized BALB/c individuals.


Assuntos
Compostos Azo/imunologia , Idiótipos de Imunoglobulinas/imunologia , p-Azobenzenoarsonato/imunologia , Animais , Anticorpos Anti-Idiotípicos/fisiologia , Anticorpos Monoclonais/fisiologia , Células Produtoras de Anticorpos/metabolismo , Linfócitos B/imunologia , Linfócitos B/metabolismo , Contagem de Células , Reações Cruzadas , Hemocianinas/imunologia , Idiótipos de Imunoglobulinas/biossíntese , Lipopolissacarídeos/farmacologia , Camundongos , Camundongos Endogâmicos A , Camundongos Endogâmicos BALB C , Coelhos
4.
J Exp Med ; 169(2): 519-33, 1989 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-2492056

RESUMO

We have found that syngeneic Ab2s in the antiarsonate system are serologically and structurally similar to one another. In contrast, the allogeneic Ab2 response is heterogeneous and derives from a large number of unrelated germline gene segments. The Ab2 response of the BALB/c strain to polyclonal A/J Ars A molecules can probably best be compared with a response to a foreign protein and might have been predicted in a strain that completely lacks the H chain V region gene from which the Ab1 derives. Partial variable region sequences of Ab2s from three other systems in addition to previously reported Ab2 structures indicates that this difference in allogeneic vs. syngeneic Ab2s may be a general phenomena. These data support Jerne's hypothesis of complementary V region genes existing in the germline. However, there is good evidence that these antiidiotypic antibodies are not derived directly from the germline, as somatic processes most likely play an important role in their generation. The D segments of Ab2s in the arsonate system as well as in other systems, are novel in structure and cannot easily be explained by previously described germline D segments. D-D fusion may play a role in the generation of the third hypervariable region in these antibodies.


Assuntos
Anticorpos Anti-Idiotípicos/genética , Rearranjo Gênico do Linfócito B , Genes de Imunoglobulinas , Idiótipos de Imunoglobulinas/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/imunologia , Sequência de Bases , Cadeias Pesadas de Imunoglobulinas/genética , Região Variável de Imunoglobulina/genética , Cadeias kappa de Imunoglobulina/genética , Camundongos , Dados de Sequência Molecular , p-Azobenzenoarsonato/imunologia
5.
Rev Med Liege ; 65(9): 510-3, 2010 Sep.
Artigo em Francês | MEDLINE | ID: mdl-21086583

RESUMO

The uterine inversion defines itself anatomically as the invagination of the uterine bottom "finger of glove" until be able to at most express itself in the vulva. It is a dramatic accident of the delivery and a sporadic occurrence in countries with low medical entity, this rarity which can mislead the practitioner, the delay of the diagnosis ends in redoubtable complications even the maternal death. Through a retrospective study concerning six case reports brought together within CHU Hassan II of Fez spreading out over eight years and review of literature, we try to describe different aspects epidemiological, etiologic, therapeutic and prognosis of this rather particular entity.


Assuntos
Transtornos Puerperais/diagnóstico , Inversão Uterina/diagnóstico , Adulto , Feminino , Humanos , Dor Pélvica/etiologia , Hemorragia Pós-Parto/etiologia , Gravidez , Transtornos Puerperais/terapia , Estudos Retrospectivos , Inversão Uterina/terapia
6.
Heliyon ; 6(12): e05698, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33364485

RESUMO

INTRODUCTION: Histological chorioamnionitis or "intrauterine inflammation or infection" (Triple I) it is an acute inflammation of amniotic membrane, chorionic plate and umbilical cord. SUBJECT: To assess in the event of the clinical predictive factors associated to histological chorioamnionitis. METHODS: Prospective examination of 50 placentas from aberrant pregnancies, and 50 placentas from 'normal' deliveries. The Placentas analyzed by the conventional histopathology method, and the severity of chorioamnionitis was classified histologically according to the intensity and the topography of placental inflammation.The clinical and histopathological features of the study groups were introduced into the SPSS 13 database (License University Mohammed V-Rabat). RESULTS: 36/50 placentas of aberrant pregnancies showed a histological chorioamnionitis often associated to a funisitis, and 11/50 normal placentas have shown some lesions of histological chorioamnionitis mainly grade one without funisitis.On the other hand we noted a statistically significant association between histological chorioamnionitis and premature rupture of the membranes (PROM) over than 12h (p < 0.001). CONCLUSIONS: Our study confirmed the predominance of histological chorioamnionitis lesions in clinically suspected cases of chorioamnionitis with 72% versus 22% in the controls group.Among the clinical parameters studied, only the premature rupture of the Membranes was shown a statistically significant association with the appearance of histological signs of chorioamnionitis.In conclusion, chorioamnionitis is sometimes clinically silent. Morphological placental study could be a confirmation of this pathology, which is predominantly associated to PROM over than 12 h.

7.
Gastroenterol Clin Biol ; 32(10): 858-65, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18775614

RESUMO

INTRODUCTION: The purpose of this clinical trial was to determine in routine practice and in comparison with liver biopsy the limitations of two blood tests, Actitest and Fibrotest, for the evaluation of hepatic activity and fibrosis in patients with chronic hepatitis C. METHODS: Routine blood tests, Actitest and Fibrotest, and liver biopsy were performed in 96 patients with chronic hepatitis C attending routine outpatient clinics. Receiver operating characteristics (ROC) curves were used to assess the diagnostic value of the biochemical tests in comparison with the METAVIR classification. RESULTS: The study population was predominantly male (63.5%) with a mean age of 48 years; 83.3% of the patients had genotype 1 hepatitis C virus infection. Treatment status was naive (62.5%), nonresponders (17.7%), relapsers (7.3%), or unknown (12.5%). The comparison of F0-F2 versus F3-F4 estimated the negative predictive value at 92% and the positive predictive value at 52% for a cut-off of 0.455. Discrepancies in activity score were more frequently due to a higher score of the biochemical test compared to biopsy (18 cases out of 19). Discrepancies for fibrosis were observed in 18 patients with a higher score for biochemical test in eight and a higher score for liver biopsy in 10 cases. A significant increase of gamma-glutamyl-transferase (GGT) (p=0.0001) and alanine aminotransferase (ALT) (p<0.0001) was observed in case of biochemical test overestimation of activity, and a significant increase of alpha2-macroglobulin (p=0.006) and GGT (p=0.018) in case of biochemical test overestimation of fibrosis. CONCLUSION: This prospective study confirms the good diagnostic value of biochemical tests for necrotico-inflammatory activity and fibrosis as compared with the histological analysis of liver biopsy. Clinicians must interpret Actitest and Fibrotest results with caution in patients with a significant elevation of ALT, and/or GGT and/or alpha2-macroglobulin which could overestimate hepatic injury.


Assuntos
Hepatite C Crônica/sangue , Hepatite C Crônica/patologia , Cirrose Hepática/sangue , Cirrose Hepática/patologia , Fígado/patologia , Adulto , Idoso , Biomarcadores/sangue , Biópsia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
8.
J Thromb Haemost ; 5(7): 1469-76, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17445092

RESUMO

BACKGROUND: As the publication of the sequence of the factor VIII gene (FVIII) in 1984, a large number of mutations that cause hemophilia A (HA) have been identified. Thanks to the advances in the detection of mutations, it is now possible to identify a putative FVIII sequence alteration in the vast majority of patients with HA. OBJECTIVES: Our main objective was to report on the spectrum of FVIII mutations and their distribution throughout the gene in 120 patients with HA. METHODS: Screening of FVIII mutations was performed using direct sequencing. Newly described missense mutations were further studied by molecular modeling. RESULTS: A total of 47 different HA causative FVIII mutations have been identified, 26 of which are described for the first time. These novel mutations include 14 missense and six nonsense mutations, two small deletions, one large deletion and three splice-site mutations. We further investigated the development of FVIII-specific inhibitors in all patients with HA. We found that four novel mutations (Ser882X, Tyr1786Ser, Ala2218Thr and a splice-site defect in intron 22) were associated with inhibitor development. CONCLUSION: These data extend our insight into the mechanisms by which novel amino acid substitutions may lead to HA, and how HA patient genotypes influence the risk of FVIII inhibitor development.


Assuntos
Fator VIII/antagonistas & inibidores , Fator VIII/genética , Hemofilia A/sangue , Hemofilia A/genética , Mutação , Substituição de Aminoácidos , Códon sem Sentido , Análise Mutacional de DNA , Fator VIII/química , Genótipo , Humanos , Masculino , Modelos Moleculares , Mutação de Sentido Incorreto , Estrutura Terciária de Proteína , Fatores de Risco , Deleção de Sequência
9.
Mol Immunol ; 26(9): 859-64, 1989 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2601726

RESUMO

The anti-ARS immune response of A/J mice is characterized by the reproducible and dominant selection of CRIA bearing antibodies. In this report, we have investigated the role of affinity for the antigen in the selection of antibody repertoire during an immune response. A/J anti-ARS responses with different ranges of affinities for arsonate were elicited by the injection of differently arsanylated carrier proteins. The selection of higher affinity A/J anti-ARS responses was shown to be associated with the induction of higher levels of CRIA bearing anti-ARS antibodies. A detailed idiotopic analysis also showed a more precocious selection of the CRIA "canonical combination" in the higher affinity anti-ARS responses. These results strongly suggest an important role for affinity and clonal selection in the dominant expression of the CRIA idiotype in the A/J anti-ARS response.


Assuntos
Arseniatos/imunologia , Arsênio/imunologia , Idiótipos de Imunoglobulinas/imunologia , Animais , Afinidade de Anticorpos , Formação de Anticorpos , Hemocianinas/imunologia , Idiótipos de Imunoglobulinas/genética , Memória Imunológica , Camundongos , Camundongos Endogâmicos A
10.
Mol Immunol ; 20(10): 1073-80, 1983 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-6201725

RESUMO

Monoclonal antibodies have been prepared from one BALB/c mouse immunized with tobacco mosaic virus. The monoclonal antibodies are distributed into three subgroups recognizing different epitopes on tobacco mosaic virus subunits. The idiotypic specificities of these monoclonal antibodies have been studied using syngeneic antiidiotypic sera. A sharing of idiotypic specificities has been observed between members of each subset. These idiotypes are not recurrent in BALB/c mice immunized with tobacco mosaic virus.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , Idiótipos de Imunoglobulinas/imunologia , Vírus do Mosaico do Tabaco/imunologia , Animais , Especificidade de Anticorpos , Ligação Competitiva , Epitopos/imunologia , Imunoglobulina G/classificação , Focalização Isoelétrica , Camundongos , Camundongos Endogâmicos BALB C
11.
Viral Immunol ; 6(1): 35-42, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8386516

RESUMO

Two mutant viruses, HSV-2 XD192 and HSV-1 1716, failed to generate zosteriform lesions when injected in high dose into BALB/c and C3H mice. Mice exposed to mutant viruses were solidly immune to challenge by wild-type homologous or heterologous virus. However, at lower immunizing doses protection was evident against lethality, but not skin lesions, especially in the case of mutant XD192. Protection could be conferred with lymphoid cells from mutant virus immune mice and again, protection against lethality was more frequent than prevention of skin lesions. On the basis of cell fractionation studies, protection against lethality was assumed to be principally the function of CD8+ T lymphocytes. The implications of the results in terms of vaccine development were briefly discussed.


Assuntos
Modelos Animais de Doenças , Herpes Simples/prevenção & controle , Simplexvirus/imunologia , Vacinação , Vacinas Virais/imunologia , Animais , Encefalite/prevenção & controle , Feminino , Genoma Viral , Membro Posterior , Contagem de Leucócitos , Masculino , Camundongos , Camundongos Endogâmicos BALB C/imunologia , Camundongos Endogâmicos C3H/imunologia , Neurônios Aferentes/microbiologia , Simplexvirus/classificação , Simplexvirus/genética , Simplexvirus/isolamento & purificação , Simplexvirus/fisiologia , Subpopulações de Linfócitos T/imunologia , Vacinas Atenuadas/imunologia
12.
Toxicol Lett ; 73(3): 167-73, 1994 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8091425

RESUMO

The toxicity of isaxonine alone and in combination with the known glutathione depletor, paracetamol, was evaluated using rat hepatocyte primary cultures in vitro by measuring morphometric parameters and the leakage of intracellular lactate dehydrogenase into the culture medium. No cytotoxicity was observed with isaxonine at concentrations up to 10(-3) M, whereas paracetamol was cytotoxic at concentrations above 0.6 x 10(-3) M in the culture medium. Paracetamol cytotoxicity (0.6-3.3 x 10(-3) M) was enhanced in the presence of a non-cytotoxic concentration of isaxonine (10(-7) M). Furthermore cytotoxicity was observed when cells were exposed to a combination of non-cytotoxic concentrations of the paracetamol (0.3 x 10(-3) M) and isaxonine (10(-7) M). These findings demonstrate that isaxonine has no direct cytotoxic effect even at high concentrations. However co-administration of isaxonine with paracetamol greatly potentiates cytotoxicity. We suggest that this effect may be related to glutathione depletion within the cell but additional studies are required to verify this hypothesis.


Assuntos
Acetaminofen/toxicidade , Fígado/efeitos dos fármacos , Pirimidinas/toxicidade , Animais , Células Cultivadas , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Glutationa/metabolismo , L-Lactato Desidrogenase/efeitos dos fármacos , Fígado/citologia , Fígado/enzimologia , Fígado/metabolismo , Masculino , Ratos , Ratos Sprague-Dawley
13.
Methods Find Exp Clin Pharmacol ; 15(6): 345-50, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8231454

RESUMO

Primary cultures of vascular smooth muscle cells (SMC) were incubated with hyperlipidemic rabbit serum (HLRS) to produce intracellular lipid accumulation. Cultures were exposed to different concentrations of the test compounds and their effects upon cell proliferation and intracellular lipid accumulation were measured. The in vitro results obtained with different Ca2+ antagonists, a HMG-CoA reductase inhibitor and other hypolipidemic substances showed a strong correlation with the in vivo activities of these compounds, suggesting that cultured SMC may be a useful initial in vitro model to detect new chemical entities active upon atherosclerosis related parameters.


Assuntos
Metabolismo dos Lipídeos , Músculo Liso Vascular/efeitos dos fármacos , Animais , Bloqueadores dos Canais de Cálcio/farmacologia , Divisão Celular/efeitos dos fármacos , Células Cultivadas , Inibidores de Hidroximetilglutaril-CoA Redutases , Hipolipemiantes/farmacologia , Músculo Liso Vascular/citologia , Músculo Liso Vascular/metabolismo , Coelhos , Ratos , Ratos Wistar
14.
Lab Anim ; 27(4): 368-73, 1993 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8277711

RESUMO

Blood samples (n = 135) were collected from 36 male and 35 female 20 +/- 4-week-old Yucatan micropigs and were analysed for 19 haematological and 18 plasma biochemical parameters at weeks 20, 24, 33, 46, 59, 71 and 80. For each parameter, the total number of analyses per sex, mean values, standard deviation, lowest and highest values, and 95% confidence intervals are presented as reference values for this breed. Age- and sex-related differences in these parameters are also discussed.


Assuntos
Porco Miniatura/sangue , Animais , Análise Química do Sangue/veterinária , Feminino , Testes Hematológicos/veterinária , Masculino , Padrões de Referência , Suínos
18.
Sex Transm Infect ; 80(1): 24-9, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-14755031

RESUMO

BACKGROUND: In two phase III vaccine trials immunisation of women previously uninfected by herpes simplex virus provided protection against genital herpes disease. In deciding policy, an evaluation of the epidemiological impact of the partial protection provided by the vaccine should be considered. METHODS: A sex and sexual activity stratified deterministic differential and partial differential equation model of the natural history of herpes simplex virus type 2 (HSV-2) and the impact of vaccination is developed and analysed. To explore the role of vaccination, the pattern of viral shedding and the transmission of infection during sexual acts within sexual partnerships are described. RESULTS: Using literature derived estimates of parameter values and assuming efficacy in only 40% of women the impact of the vaccine depends on assumptions made about its action. The vaccine has a limited impact if it only prevents disease but a more substantial impact if it reduces asymptomatic viral shedding, which it could do indirectly by preventing infection or directly by modifying the biology of the infection. Concern over the implications of a vaccine that prevents disease but has no impact on viral shedding was addressed in a worst case scenario. Here there is a modest increase in the incidence of infection in both men and women but an increase in disease prevalence in men alone, since the virus directly protects some women from disease. CONCLUSIONS: Results suggest that a herpes vaccine should be used universally and that a vaccine that only protects HSV-1-/2- women can paradoxically have a significant epidemiological impact, the scale of which depends upon changes in patterns of viral shedding.


Assuntos
Herpes Genital/prevenção & controle , Vacinas contra o Vírus do Herpes Simples , Herpesvirus Humano 2 , Ensaios Clínicos Fase III como Assunto , Feminino , Herpes Genital/epidemiologia , Herpes Genital/transmissão , Humanos , Modelos Biológicos , Fatores de Risco , Comportamento Sexual , Parceiros Sexuais , Vacinação , Eliminação de Partículas Virais
19.
J Virol ; 63(2): 952-4, 1989 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-2463386

RESUMO

The fusion gene sequence of six Newcastle disease virus escape mutants revealed that residues important for the integrity of antigenic site 1 and antigenic site 2 were located, respectively, on the F2 subunit and within the cysteine-rich domain of the F1 subunit. We further report the antibody-binding capacity of these mutants.


Assuntos
Antígenos Virais/genética , Vírus da Doença de Newcastle/genética , Proteínas Virais de Fusão/genética , Sequência de Aminoácidos , Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , Antígenos Virais/imunologia , Epitopos/genética , Dados de Sequência Molecular , Testes de Neutralização , Vírus da Doença de Newcastle/imunologia , Ligação Proteica , Proteínas Virais de Fusão/imunologia
20.
Immunology ; 68(1): 1-6, 1989 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2530152

RESUMO

The T-cell differentiation antigen, CD4, is expressed by major histocompatibility (MHC) class II restricted T lymphocytes. CD4+CD8- T cells use their T-cell receptor to recognize foreign antigens in association with MHC class II products (Ia). The association between CD4 expression and restriction by MHC class II products has led to the hypothesis that CD4 may interact with monomorphic determinants of MHC class II molecules. A large body of experimental evidence suggests that CD4 interaction with MHC class II molecules leads to an increase in the binding avidity of T cell-stimulator cell interactions. A direct test for a functional CD4-MHC class II interaction in T-cell activation requires a separate evaluation of CD4-Ia interactions from T-cell receptor (TcR)-antigen (Ag)/Ia recognition. However, a separate evaluation proves difficult since the T-cell receptor and CD4 may interact with the same MHC class II molecule. In this report, we use a T-cell activation protocol where TcR-Ag/Ia recognition is replaced by TcR complex-anti-CD3 antibody interactions. Therefore, the affinity of the TcR complex for its ligand (the anti-CD3 mAb) is independent from MHC expression on target cells and allows a separate evaluation of the role of accessory molecules in T-cell activation. We have analysed the effects of monoclonal anti-MHC class II antibodies on the activation of a CD4+ T-cell hybridoma in the absence of its TcR restricting MHC class II molecule (I-Ek) but in the presence of unrelated MHC class II molecules (I-Ed, I-Ad). The data obtained indicate a functional interaction between the CD4 molecule and a non-polymorphic region of the MHC class II product in T-cell triggering.


Assuntos
Antígenos CD4/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Ativação Linfocitária , Receptores de Antígenos de Linfócitos T/imunologia , Animais , Anticorpos Monoclonais/imunologia , Antígenos de Diferenciação de Linfócitos T/imunologia , Complexo CD3 , Células Cultivadas , Camundongos
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