RESUMO
BACKGROUND/AIMS: Self sampling is considered an adjuvant tool to facilitate the participation of women in cervical cancer screening programmes. This study aimed to evaluate whether cervicovaginal lavage could be an alternative for the cervical smear in cytology and human papillomavirus (HPV) testing and to assess the acceptance of the self sampling device by women. METHODS: Fifty six women with abnormal cervical cytology (very mild dyskaryosis or worse) and 15 women with normal cervical cytology obtained a self collected cervicovaginal lavage at home and filled in a questionnaire on the use of the device. At the colposcopy clinic the gynaecologist performed the same procedure followed by a cervical smear for cytology and HPV DNA testing. RESULTS: The self sampling device was acceptable to 88% of the women. The concordance between the cytology results in the smear and the lavage by the doctor and the patient was 54% and 41%, respectively (kappa = 0.28 and 0.14). The concordance between high risk HPV detection in the smear and the lavage by the doctor and the patient was 93% and 78%, respectively (kappa = 0.82 and 0.53). Ninety one per cent of the women with high grade cervical intraepithelial neoplasia (CIN) had a high risk HPV positive test in the smear, compared with 91% and 81% in the lavages taken by the doctor and the patient, respectively. CONCLUSIONS: HPV DNA testing by home obtained samples is useful as a screening tool for cervical cancer, whereas cervical cytology by self sampling is not. Although the sensitivity for high grade CIN by high risk HPV testing in the lavage by the patient is not significantly lower than that in the cervical smear, self sampling for HPV DNA is a feasible alternative method in women who decline to participate in population based cervical cancer screening programmes. However, participation in the screening programme remains the best option.
Assuntos
Papillomaviridae/isolamento & purificação , Infecções por Papillomavirus/diagnóstico , Autocuidado/métodos , Infecções Tumorais por Vírus/diagnóstico , Displasia do Colo do Útero/virologia , Neoplasias do Colo do Útero/virologia , Adulto , Feminino , Humanos , Programas de Rastreamento/métodos , Pessoa de Meia-Idade , Infecções por Papillomavirus/complicações , Satisfação do Paciente , Manejo de Espécimes/métodos , Inquéritos e Questionários , Irrigação Terapêutica , Infecções Tumorais por Vírus/complicações , Neoplasias do Colo do Útero/diagnóstico , Esfregaço Vaginal/métodos , Displasia do Colo do Útero/diagnósticoRESUMO
CD97 is a founding member of the EGF-TM7 family of class II seven-span transmembrane (7-TM) receptors. CD97 has an extended extracellular region with several N-terminal epidermal growth factor (EGF)-like domains, which mediate binding to CD55. Previous studies demonstrated the expression of CD97 on activated lymphocytes, monocytes, macrophages, granulocytes, and numerous haematopoietic and nonhaematopoietic cell lines. Here, we determined the cellular distribution of human CD97 in situ by immunohistochemistry (IH) and immunofluorescence (IF). Abundant expression of CD97 was detected on all types of macrophages and dendritic cells, except for microglia. Within the lymphoid lineage, most T cells but only a few B cells express CD97. Germinal centre B cells do not express the molecule. Except for smooth muscle cells, no staining was found on other cells outside the immune system. However, analysis of a restricted set of epithelial tumors revealed CD97 expression on the malignant cells in thyroid and gastrointestinal tract cancer.
Assuntos
Fator de Crescimento Epidérmico/metabolismo , Glicoproteínas de Membrana/metabolismo , Especificidade de Órgãos/imunologia , Anticorpos Monoclonais/metabolismo , Antígenos CD , Sítios de Ligação de Anticorpos , Antígenos CD55/biossíntese , Antígenos CD55/imunologia , Antígenos CD55/metabolismo , Carcinoma/imunologia , Fator de Crescimento Epidérmico/imunologia , Humanos , Tecido Linfoide/citologia , Tecido Linfoide/imunologia , Glicoproteínas de Membrana/biossíntese , Glicoproteínas de Membrana/imunologia , Músculo Liso/citologia , Músculo Liso/imunologia , Células Mieloides/imunologia , Receptores Acoplados a Proteínas GRESUMO
BACKGROUND/AIMS: Killer inhibitory receptors (KIR) have a modulating effect on the cytotoxic functions of natural killer (NK) cells and T cells. Because lymphoma cells often have the same receptors as their non-neoplastic counterparts, this study investigated the expression of KIR on well defined groups of NK and T cell lymphomas, with and without a cytotoxic phenotype, from different sites of origin. METHODS: Nine CD56+/CD3- NK cell lymphomas, 29 CD3+/CD56- T cell lymphomas with a cytotoxic phenotype, and 19 T cell lymphomas without a cytotoxic phenotype were stained for KIR using monoclonal antibodies specific for CD94, CD158a, and CD158b. In addition, the expression of KIR was studied on normal lymphoid tissues. RESULTS: KIR expression was seen in five of nine true NK cell lymphomas including three of four nasal, one of four cutaneous, and one of one intestinal lymphoma nasal type. Double staining for CD56 and CD94 in normal lymphoid tissues revealed that KIR was predominantly expressed by CD56+ NK cells and sporadically on CD8+ T cells. Moreover, enteropathy-type T cell lymphomas with a cytotoxic phenotype showed KIR expression (three cases expressing CD94 and one case expressing CD158a). All nodal and extranodal nonintestinal T cell lymphomas with or without a cytotoxic phenotype lacked expression of KIR. CONCLUSIONS: These results show that KIR expression is restricted to CD56+/CD3- true NK cell lymphomas originating from the nose, gut, and skin, as well as in a subset of extranodal T cell lymphomas originating from the small intestine, which possessed a cytotoxic phenotype. Thus, the presence of KIR on NK/T cell lymphomas seems to mimic the distribution of KIR found on NK and T cells in normal lymphoid tissue.
Assuntos
Células Matadoras Naturais/metabolismo , Linfoma/metabolismo , Receptores Imunológicos/metabolismo , Complexo CD3/análise , Antígeno CD56/análise , Humanos , Técnicas Imunoenzimáticas , Imunofenotipagem , Neoplasias Intestinais/imunologia , Neoplasias Intestinais/metabolismo , Linfoma/imunologia , Linfoma de Células T/imunologia , Linfoma de Células T/metabolismo , Neoplasias Nasofaríngeas/imunologia , Neoplasias Nasofaríngeas/metabolismo , Proteínas de Neoplasias/metabolismo , Receptores KIR , Receptores KIR2DL1 , Receptores KIR2DL3 , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/metabolismo , Linfócitos T Citotóxicos/metabolismoRESUMO
Hodgkin's disease (HD) is a malignant lymphoproliferative disease characterized by the presence of Hodgkin-Reed-Sternberg cells surrounded by a reactive infiltrate. In Epstein-Barr virus (EBV)-associated cases (40-60%), at least two EBV-encoded proteins [latent membrane protein 1 (LMP1) and LMP2] are expressed, which are potential targets for cytotoxic T-lymphocytes (CTLs). Although in EBV-positive cases significantly more activated (granzyme B-positive) CTLs and natural killer (NK) cells are present, the cytotoxic immune response is not sufficient for adequate killing of tumour cells. The production of immunomodulating cytokines within the tumour may be one of the mechanisms causing circumvention of the immune system. This study investigated by immunohistochemistry the presence of the immunosuppressive cytokine interleukin-10 (IL-10) and other Th1/Th2-associated cytokines [IL-2, IL-4, interferon-gamma (IFN-gamma)] in the neoplastic cells and reactive lymphocytes of nine EBV-positive and 18 EBV-negative cases of HD. The percentage of IL-10-expressing cells, both neoplastic and reactive, in EBV-positive cases was significantly higher (33.1% vs. 18.5% for the neoplastic cells and 21.6% and 12.2% for the reactive cells, p=0.003 and 0.04, respectively) than in EBV-negative cases. No difference in the percentage of IL-2-, IL-4- and IFN-gamma-expressing cells was observed. These results suggest that escape from local immune surveillance is not due to a shift from Th1 towards Th2, but may be caused by a direct effect of IL-10 on the cytotoxic cells.
Assuntos
Citocinas/metabolismo , Herpesvirus Humano 4 , Doença de Hodgkin/imunologia , Doença de Hodgkin/virologia , Proteínas de Neoplasias/metabolismo , Citocinas/imunologia , Humanos , Tolerância Imunológica , Técnicas Imunoenzimáticas , Interleucina-10/imunologia , Interleucina-10/metabolismo , Proteínas de Neoplasias/imunologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Subpopulações de Linfócitos T/imunologia , Células Tumorais Cultivadas , Proteínas Virais/imunologia , Proteínas Virais/metabolismoRESUMO
AIM: To investigate whether anaplastic large cell lymphomas (ALCL) expressing cytotoxic proteins have a relatively worse clinical outcome compared with ALCL lacking a cytotoxic phenotype. METHODS: 59 primary cases of ALCL originating from different sites were investigated by immunohistochemistry for the presence of the cytotoxic proteins T cell intracytoplasmic antigen (TIA-1) and granzyme B in the neoplastic cells. Since site of origin and expression of anaplastic lymphoma kinase (ALK) strongly influence prognosis, the presence of a cytotoxic phenotype was also investigated in relation to the primary site of origin (lymph node, gut, or skin) and ALK expression. The prognostic value was investigated by analysis of overall and relapse-free survival time, including Cox regression analysis. RESULTS: 39 of 59 ALCL (66%) appeared to have a cytotoxic phenotype as shown by expression of TIA-1 or granzyme B or both in the neoplastic cells. The presence of a cytotoxic phenotype did not have any influence on prognosis. Even when the survival data were corrected for site of origin and stage at presentation or were analysed separately for ALK positive and negative cases, no prognostic influence of a cytotoxic phenotype was observed. CONCLUSIONS: In primary biopsies of patients with ALCL, the presence of a cytotoxic phenotype is not related to clinical outcome of the disease.
Assuntos
Biomarcadores Tumorais/metabolismo , Linfoma Anaplásico de Células Grandes/imunologia , Proteínas de Membrana/metabolismo , Proteínas , Proteínas de Ligação a RNA/metabolismo , Serina Endopeptidases/metabolismo , Linfócitos T Citotóxicos/imunologia , Adulto , Idoso , Feminino , Seguimentos , Fator Estimulador de Colônias de Granulócitos/metabolismo , Granzimas , Humanos , Técnicas Imunoenzimáticas , Imunofenotipagem , Masculino , Pessoa de Meia-Idade , Proteínas de Neoplasias/metabolismo , Proteínas de Ligação a Poli(A) , Prognóstico , Taxa de Sobrevida , Antígeno-1 Intracelular de Células T , Subpopulações de Linfócitos T/imunologiaRESUMO
BACKGROUND: Rises in circulating C-reactive protein (CRP), the prototypical acute-phase protein in humans, correlate with clinical outcome in patients with myocardial ischemia and infarction. We hypothesized that these correlations might reflect active participation of CRP in the local inflammatory response ensuing in the jeopardized myocardium because on binding to a ligand, CRP is able to activate the classic pathway of complement, and in addition, complement activation has been shown to occur locally in infarcted myocardium. METHODS AND RESULTS: To verify our hypothesis, we investigated localization of CRP in relation to deposition of complement in tissue specimens of infarcted and healthy heart tissue obtained from 17 patients who had died after acute myocardial infarction. CRP was found to be deposited only in infarcted regions and not in normal-appearing areas of the myocardium, being colocalized with depositions of C4 and C3 activation fragments of the complement system. Deposition of CRP and complement in infarcted myocardium appeared to be time dependent, because it was found in all infarctions except for one of young age (< 12 hours old) and two of greater age (> 1 year old), whereas another tissue specimen of an infarct < 12 hours old showed only moderate but positive staining for both CRP and complement in comparison with older infarctions. CONCLUSIONS: We conclude that in humans, CRP may localize in infarcted heart tissue and suggest that this acute-phase protein promotes local complement activation, and hence tissue damage, in acute myocardial infarction.
Assuntos
Proteína C-Reativa/análise , Proteínas do Sistema Complemento/análise , Infarto do Miocárdio/patologia , Miocárdio/química , Idoso , Ativação do Complemento , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/imunologiaRESUMO
Laminins are a family of multifunctional basement membrane glycoproteins. Over the last years, many laminin isoforms have been characterized, which were shown to be composed of distinct combinations of variant alpha, beta and gamma chains. Some of these isoforms show remarkable tissue specificity, which suggests functional involvement in local processes. In this study the previously described mAb 4C7, which recognize epithelial basement membranes as well as endothelial basement membranes in lymphoid follicles, was identified as an anti-laminin-5 antibody. Using a set of mAbs against various variant laminin chains we established that specifically the gamma 2 chain of laminin-5 was confined to the endothelial basement membranes of vessels in lymphoid follicles, whereas other variant laminin chains were also expressed elsewhere in the lymphoid follicles, whereas other variant laminin chains were also expressed elsewhere in the lymphoid tissue. Additionally, the expression of the known integrin receptors of laminin-5 was also examined. The alpha 6 beta 4 integrin-receptor for laminin was found to be colocalized with the laminin-5 gamma 2 chain on the abluminal surface of endothelial cells, whereas the alpha 3 integrin chain could not be detected in lymphoid follicles. This finding suggests that the alpha 6 beta 4 integrin (and not the alpha 3 beta 1 integrin) serves as a laminin-5 receptor on endothelial cells in the follicular compartment of lymphoid tissue. Furthermore, alpha 6 beta 4 was also found in the same punctuated pattern on FDCs as laminin-5. The function of the laminin-alpha 6 beta 4 complex in this particular localisation is still obscure, but a role in the maintainance of the follicular compartment via hemidesmosome-like attachment sites is postulated.
Assuntos
Antígenos de Superfície/isolamento & purificação , Moléculas de Adesão Celular/isolamento & purificação , Integrinas/isolamento & purificação , Tecido Linfoide/química , Receptores de Laminina/isolamento & purificação , Anticorpos Monoclonais , Especificidade de Anticorpos , Membrana Basal/química , Membrana Basal/ultraestrutura , Moléculas de Adesão Celular/imunologia , Endotélio/química , Endotélio/ultraestrutura , Humanos , Imuno-Histoquímica , Integrina alfa6beta4 , Tecido Linfoide/irrigação sanguínea , Tecido Linfoide/ultraestrutura , Tonsila Palatina/química , Tonsila Palatina/ultraestrutura , Distribuição Tecidual , CalininaRESUMO
We report a patient with mycosis fungoides (MF) and transformation to anaplastic (CD30+) lymphoma, who developed an unusual manifestation in the breast. Cutaneous and extracutaneous tumour cells both showed marked intraepithelial migration, but had distinct expression patterns of epitheliotropism-associated integrins. Intraepidermal and dermal lymphoma cells in the skin expressed most of the integrins that are presumed to be involved in epitheliotropism, such as leucocyte functional antigen-1 (LFA-1), alpha 1 beta 1, alpha 3 beta 1, alpha 4 beta 1 and alpha 6 beta 1. In the breast, most of the extraepithelial tumour cells only expressed the laminin-5 ligand alpha 3 beta 1 (strong) and the collagen ligand alpha 1 beta 1 (weak). However, on the intraepithelial tumour cells in the mammary ducts and glands LFA-1, alpha 4 and alpha E could also be detected. In view of these findings we propose epitheliotropism of the MF cells in the breast to be a multistep process in which tumour cell-epithelial basement membrane (EBM) interaction, predominantly mediated by alpha 3 beta 1 and laminin-5, is the primary event. Adhesion to and subsequent infiltration of the neoplastic lymphoid cells into the EBM may, either directly or indirectly, lead to upregulation and/or activation of other integrins that amplify interaction with epithelial cells.
Assuntos
Neoplasias da Mama/secundário , Micose Fungoide/patologia , Neoplasias Cutâneas/patologia , Neoplasias da Mama/química , Neoplasias da Mama/patologia , Feminino , Humanos , Integrinas/análise , Linfoma Anaplásico de Células Grandes/patologia , Pessoa de Meia-Idade , Micose Fungoide/química , Proteínas de Neoplasias/análise , Neoplasias Cutâneas/químicaRESUMO
Intraepithelial migration of lymphoid cells (epitheliotropism) is a biological process that can be observed under various physiological and pathological conditions. Recently, epitheliotropism was proposed to be a multi-step process, involving interactions of lymphoid cells with both epithelial basement membrane (EBM) and epithelial cells. In the present study we analysed by immunohistochemistry the adhesion mechanisms that are potentially involved in epitheliotropism of lymphoid cells in various disorders, such as tonsillar hyperplasia, coeliac disease, malignant lymphomas of mucosa-associated lymphoid tissue (MALTomas), and mycosis fungoides (MF). The combinations of adhesion molecules expressed on the participating lymphoid and epithelial cells varied among these disorders. These findings suggest that the adhesion pathways utilized in epitheliotropism may be associated with the nature of the lymphoid cell (reactive or neoplastic/B or T) and/or the site of the epithelium involved. In some cases the specificity of the process was determined by the adhesion mechanism involved in the lymphocyte-EBM interaction, as in the case of alpha 3 beta 1 integrin/laminin-5 in MF, and in others by the adhesion mechanisms involved in the interaction between lymphoid and epithelial cells, such as alpha 4 integrin/VCAM-1 in tonsillar hyperplasia and alpha E beta 7/E-cadherin in coeliac disease.
Assuntos
Moléculas de Adesão Celular/fisiologia , Linfócitos/patologia , Micose Fungoide/patologia , Tonsila Palatina/patologia , Neoplasias Cutâneas/patologia , Doença Celíaca/metabolismo , Doença Celíaca/patologia , Adesão Celular/fisiologia , Movimento Celular/fisiologia , Epitélio/patologia , Humanos , Hiperplasia/metabolismo , Hiperplasia/patologia , Técnicas Imunoenzimáticas , Linfoma de Zona Marginal Tipo Células B/metabolismo , Linfoma de Zona Marginal Tipo Células B/patologia , Micose Fungoide/metabolismo , Neoplasias Cutâneas/metabolismoRESUMO
Since non-Hodgkin's lymphoma (NHL) cells interact with surrounding structures similarly to their normal counterparts, micro-environmental changes and the aberrant expression of adhesion molecules are considered to be of importance in lymphomagenesis. In this immunohistochemical study, the composition of several extracellular matrix (ECM) components and the expression of their beta 1 integrin receptors were examined in nodal and extranodal T-cell NHLs. Except for the T-lymphoblastic NHLs, almost all T-NHLs displayed abundant deposition of matrix and considerable expression of the alpha 4 and beta 1 integrin chains. This is in contrast to B-cell NHLs, which show ECM patterns comparable to those in reactive lymphoid tissue or, in cases of high-grade malignancy, active matrix degradation and very low expression or absence of beta 1 integrins, as previously described. This difference is probably based on distinct cytokine production in B- and T-cell malignancies. As in B-NHL, nodal and extranodal T-NHLs of the same morphological subtype exhibit identical ECM patterns, which suggests that malignant lymphoid cells of both B and T origin create at least part of their own specific micro-environment.
Assuntos
Proteínas da Matriz Extracelular/metabolismo , Integrina beta1/metabolismo , Linfoma de Células T/metabolismo , Proteínas de Neoplasias/metabolismo , Colágeno/metabolismo , Fibronectinas/metabolismo , Humanos , Técnicas Imunoenzimáticas , Laminina/metabolismo , Linfoma Cutâneo de Células T/metabolismo , Linfoma de Células T Periférico/metabolismo , Neoplasias Cutâneas/metabolismoRESUMO
In this study the distribution patterns of various extracellular matrix components and their receptors (i.e. beta 1 integrins) in B-cell non-Hodgkin lymphomas were examined and compared to those in reactive lymphoid tissue. Neoplastic follicles within follicular lymphomas showed similar patterns to that observed in reactive follicles, which appeared to be strongly associated with the presence of follicular dendritic cells. Diffuse lymphomas of low and intermediate malignancy grade revealed features comparable to those of interfollicular areas of reactive lymphoid tissue, irrespective to which compartment the tumour cells were related. Highly malignant lymphomas, however, displayed unique extracellular matrix configurations, resulting from active matrix degradation by macrophages; this may support rapid tumour growth. Extranodal lymphomas showed virtually the same matrix patterns as their nodal counterparts, suggesting that (malignant) lymphoid cells generate (at least partly) their own specific microenvironment. In reactive lymphoid tissue beta 1 integrins were mainly found on resident cells and except for alpha 4, alpha 5 (and beta 1) the lymphoid cells expressed very little, if any, beta 1 integrins. In comparison, expression of these integrins on lymphoma cells was reduced (follicular lymphomas) or could not be detected at all (diffusely growing lymphomas); this might contribute to the growth pattern and metastatic properties of the tumours.
Assuntos
Proteínas da Matriz Extracelular/análise , Integrinas/análise , Tecido Linfoide/química , Linfoma de Células B/química , Moléculas de Adesão Celular Neuronais/análise , Colágeno/análise , Fibronectinas/análise , Humanos , Integrina beta1 , Laminina/análise , Tecido Linfoide/patologia , Linfoma de Células B/patologia , TenascinaRESUMO
Previously, we have establish K562 transfectants that express either alpha 6A beta 1 or alpha 6B beta 1 (K alpha 6A or K alpha 6B) on their surface. Both cell lines bind to laminin and kalinin after treatment with the beta 1-stimulatory antibody TS2/16. Here we introduce the full-length beta 4 cDNA into the alpha 6A- and alpha 6B-expressing K562 cells and selected stably transfected cells. The beta 4 subunit was expressed on the surface of both transfectants and it formed dimers with the alpha 6A or alpha 6B subunits. Immunoprecipitation and preclearing analyses revealed that both transfectants expressed alpha 6 beta 1, in addition to alpha 6 beta 4. While K alpha 6A and K alpha 6B cells required TS2/16 stimulation for binding to laminin or kalinin, adhesion of the unstimulated beta 4-transfected K alpha 6A and K alpha 6B cells to these matrix components was already substantial. This adhesion was mediated by both alpha 6 beta 1 and alpha 6 beta 4 since it was completely blocked by an alpha 6-specific antibody or by a combination of anti-beta 1 and anti-beta 4 antibodies, but only partially by either of these latter two antibodies alone. Adhesion to laminin was completely blocked by an antiserum to laminin fragment E8 as was the adhesion to kalinin by an antibody to kalinin, demonstrating the specificity of adhesion. Both transfectants always adhered more strongly to kalinin than to laminin. Furthermore, binding to kalinin was less well blocked by antibodies to beta 4 than binding to laminin, indicating that the affinity of alpha 6 beta 4 for kalinin is higher than that for laminin. The fact that alpha 6 beta 1 mediated adhesion without TS2/16 stimulation on the beta 4-transfected K alpha 6A and K alpha 6B cells suggests that some activation of alpha 6 beta 1 had occurred in these cells, even though binding was increased when they were actively stimulated by the antibody TS2/16. Finally, we show that Mn2+ induced binding of solubilized alpha 6 beta 4 to matrix containing kalinin, deposited by the murine cell line RAC-11P/SD. This binding was inhibited by the anti-alpha 6 mAb GoH3. Together, these results indicate that both alpha 6 beta 1 and alpha 6 beta 4 are receptors for laminin and kalinin and that there are no differences in ligand specificity between the A and B variants of the alpha 6 subunit when associated with either beta 1 or beta 4.
Assuntos
Antígenos de Superfície/metabolismo , Moléculas de Adesão Celular/metabolismo , Integrinas/metabolismo , Receptores de Laminina/metabolismo , Animais , Antígenos de Superfície/genética , Adesão Celular , Linhagem Celular , DNA Complementar/genética , Humanos , Integrina alfa6beta1 , Integrina alfa6beta4 , Integrinas/genética , Camundongos , Receptores de Laminina/genética , Transfecção , Células Tumorais Cultivadas/metabolismo , CalininaRESUMO
The ligand specificity of the alpha 3A beta 1 integrin was analyzed using K562 cells transfected with full-length alpha 3A cDNA and was compared with that of alpha 6A beta 1 in similarly transfected K562 cells. Clones were obtained that showed comparable surface expression of either alpha 3A beta 1 or alpha 6A beta 1 integrins. Those expressing alpha 3A beta 1 attached to and spread on immunopurified human kalinin and cellular matrices containing human kalinin, which is a particular isoform of laminin. In addition, alpha 3A transfectants adhered to bovine kidney laminins possessing a novel A chain variant. Binding to kalinin was blocked by a monoclonal antibody against the A chain constituent of kalinin and adhesion to both kalinin and kidney laminins by anti-alpha 3 and beta 1 monoclonal antibodies. The alpha 3A transfected cells bound more strongly to kalinin and bovine kidney laminins after treatment with the beta 1 stimulatory antibody TS2/16. A distinctly weaker and activation-dependent adhesion of alpha 3A transfectants was observed on human placental laminins possessing the Am chain variant (merosin), and no adhesion occurred on bovine heart laminins and murine EHS tumor laminin. Further inactive substrates were fibronectin, nidogen, and collagen types IV and VI, indicating that the alpha 3A beta 1 integrin is a much less promiscuous receptor than thought before. By contrast, alpha 6A transfected cells adhered to all laminin isoforms when stimulated with TS2/16. Adhesion also occurred only on bovine kidney laminins in the absence of TS2/16. These results demonstrate that both alpha 3A beta 1 and alpha 6A beta 1 integrins are typical laminin receptors but that their affinity and activation dependence for binding to various laminin isoforms differ considerably.
Assuntos
Integrinas/metabolismo , Laminina/metabolismo , Receptores de Laminina/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Bovinos , Adesão Celular , Moléculas de Adesão Celular/metabolismo , Linhagem Celular , Primers do DNA , Humanos , Integrina alfa3beta1 , Integrina alfa6beta1 , Integrinas/antagonistas & inibidores , Integrinas/genética , Laminina/química , Ligantes , Conformação Molecular , Dados de Sequência Molecular , Receptores de Fibronectina/metabolismo , Células Tumorais Cultivadas , CalininaRESUMO
In order to define compartment-related structures within the extracellular matrix of human lymphoid organs, monoclonal antibodies (MAbs) were generated by immunizing mice with stromal fragments of human tonsils. One MAb (4C7) was selected which recognized an endothelial basal membrane component that is selectively expressed in capillaries of lymphoid follicles. The epitope was also present in follicles within chronically inflamed synovial membrane and in a hyperplastic thymus of a patient with myasthenia gravis. B-cell non-Hodgkin's lymphomas with a follicular growth pattern expressed the antigen in neoplastic follicles, whereas diffuse growing lymphomas lacked the antigen. The restricted distribution pattern suggests involvement of the 4C7-defined antigen in the organization of the follicular compartment within human lymphoid tissue.