Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 2 de 2
Filtrar
Mais filtros

Base de dados
Ano de publicação
Tipo de documento
Intervalo de ano de publicação
1.
Clin Diagn Lab Immunol ; 10(1): 125-32, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12522050

RESUMO

Most conventional vaccines consist of killed organisms or purified antigenic proteins. Such molecules are generally poorly immunogenic and need to be coupled to carrier proteins. We have identified a new carrier molecule, BB, derived from the G protein of Streptococcus strain G148. We show that BB is able to induce strong antibody responses when conjugated to peptides or polysaccharides. In order to localize T and B cell epitopes in BB and match them with the albumin-binding region of the molecule, we immunized mice with BB, performed B and T pepscan analyses, and compared the results with pepscan done with sera and cells from humans. Our results indicate that BB has two distinct T helper epitopes, seven linear B-cell epitopes, and one conformational B-cell epitope in BALB/c mice. Four linear B-cell epitopes were identified from human sera, three of which overlapped mouse B-cell epitopes. Finally, three human T-cell epitopes were detected on the BB protein. One of these T-cell epitopes is common to BALB/c mice and humans and was localized in the region that contains the albumin-binding site. These data are of interest for the optimization of new carrier molecules derived from BB.


Assuntos
Proteínas de Bactérias/imunologia , Epitopos de Linfócito B/química , Epitopos de Linfócito T/química , Sequência de Aminoácidos , Animais , Proteínas de Transporte/administração & dosagem , Proteínas de Transporte/química , Proteínas de Transporte/imunologia , Mapeamento de Epitopos , Epitopos de Linfócito B/imunologia , Epitopos de Linfócito T/imunologia , Humanos , Imunização , Ativação Linfocitária/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Peptídeos/química , Peptídeos/imunologia , Polissacarídeos/química , Polissacarídeos/imunologia , Proteínas Virais/administração & dosagem , Proteínas Virais/química , Proteínas Virais/imunologia
2.
Blood ; 104(6): 1778-83, 2004 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-15166032

RESUMO

Although human CD56(+)CD3(-) natural killer (NK) cells participate in immune responses against microorganisms, their capacity to directly recognize and be activated by pathogens remains unclear. These cells encode members of the Toll-like receptor (TLR) family, involved in innate cell activation on recognition of pathogen-associated molecular patterns (PAMPs). We therefore evaluated whether the 2 bacterial protein PAMPs, the outer membrane protein A from Klebsiella pneumoniae (KpOmpA) and flagellin, which signal through TLR2 and TLR5, respectively, may directly stimulate human NK cells. These proteins induce interferon-gamma (IFN-gamma) production by NK cells and synergize with interleukin-2 (IL-2) and proinflammatory cytokines in PAMP-induced activation. Similar results were obtained using CD56(+)CD3(+) (NKR-expressing) T cells. NK cells from TLR2(-/-) mice fail to respond to KpOmpA, demonstrating TLR involvement in this effect. Defensins are antimicrobial peptides expressed mainly by epithelial cells and neutrophils that disrupt the bacterial membrane, leading to pathogen death. We show that NK cells and NKR-expressing T cells constitutively express alpha-defensins and that KpOmpA and flagellin rapidly induce their release. These data demonstrate for the first time that highly purified NK cells directly recognize and respond to pathogen components through TLRs and evidence defensins as a novel and direct cytotoxic pathway involved in NK cell-mediated protection against microorganisms.


Assuntos
Proteínas da Membrana Bacteriana Externa/imunologia , Flagelina/imunologia , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Glicoproteínas de Membrana/metabolismo , Receptores de Superfície Celular/metabolismo , alfa-Defensinas/biossíntese , Animais , Células Cultivadas , Citocinas/metabolismo , Humanos , Células Matadoras Naturais/citologia , Ativação Linfocitária , Camundongos , Receptor 2 Toll-Like , Receptor 5 Toll-Like , Receptores Toll-Like , alfa-Defensinas/genética , alfa-Defensinas/metabolismo
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa