RESUMO
A major objective in vaccine development is the design of reagents that give a strong, specific T cell response. Targeting of antigens to antigen presenting cells (APC) results in enhanced antigen presentation and T cell activation. In this paper, we describe a novel targeting reagent denoted 'Troy-bodies', namely recombinant antibodies with APC-specificity and with T cell epitopes integrated in their C regions. We have made such antibodies with V regions specific for either IgD or MHC class II, and five different T cell epitopes have been tested. All epitopes could be introduced into loops of C domains without disrupting immunoglobulin (Ig) folding. Four have been tested in T cell activation studies, and all could be released and presented by APC. Furthermore, whether IgD- or MHC-specific, the molecules tested enhanced T cell stimulation compared to non-specific control antibodies in vitro as well as in vivo. Using this technology, specific reagents can be designed that target selected antigenic peptides to an APC of choice. Troy-bodies may therefore be useful for manipulation of immune responses, and in particular for vaccination purposes.
Assuntos
Anticorpos/imunologia , Células Apresentadoras de Antígenos/imunologia , Epitopos/imunologia , Engenharia de Proteínas , Linfócitos T/imunologia , Animais , Anticorpos/genética , Especificidade de Anticorpos , Antígenos de Histocompatibilidade Classe II/imunologia , Humanos , Imunoglobulina D/imunologia , Região Variável de Imunoglobulina/química , Técnicas In Vitro , Camundongos , Camundongos Endogâmicos BALB C , Modelos Estruturais , Mutagênese Insercional , Nitro-Hidroxi-Iodofenilacetato , Dobramento de Proteína , Estrutura Terciária de Proteína , Proteínas Recombinantes/imunologiaRESUMO
Targeting of antigens to antigen presenting cells (APC) results in enhanced antigen presentation and T cell activation. In this paper, we describe a novel targeting reagent denoted "Troy-bodies", namely recombinant antibodies with APC-specific V regions and C regions with integrated T cell epitopes. We have made such antibodies with V regions specific for either IgD or MHC class II, and four different T cell epitopes have been tested. All four epitopes could be introduced into loops of C domains without disrupting Ig folding, and they could be released and presented by APC. Furthermore, whether IgD- or MHC-specific, the molecules enhanced T cell stimulation compared to non-specific control antibodies in vitro as well as in vivo. Using this technology, specific reagents can be designed that target selected antigenic peptides to an APC of choice. Troy-bodies may therefore be useful for manipulation of immune responses, and in particular for vaccination purposes.
Assuntos
Anticorpos/metabolismo , Células Apresentadoras de Antígenos/imunologia , Linfócitos T/imunologia , Animais , Anticorpos/química , Apresentação de Antígeno , Epitopos/química , Epitopos/metabolismo , Antígenos de Histocompatibilidade Classe II/química , Antígenos de Histocompatibilidade Classe II/metabolismo , Humanos , Imunoglobulina D/química , Imunoglobulina D/metabolismo , Camundongos , Modelos Moleculares , Estrutura Terciária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/metabolismoRESUMO
A major objective in development of vaccines is the design of sub-unit vaccines with the ability to induce strong T-cell responses. For this purpose, T-cell epitopes have been genetically inserted into various carrier proteins. Ig molecules may be especially useful as vehicles for delivery of CD4(+) T-cell epitopes to antigen presenting cells (APC). We have previously replaced loop structures between beta-strands in the C(H)1 domain of human IgG3 with a defined 11 amino acids long, MHC class II-restricted T-cell epitope. In this report we have added the same T-cell epitope into loops in the C(H)1 domain of mouse IgG2b. The following major points can be made: (1) Loops can accommodate an elongation of at least 11 amino acids without disruption of the overall Ig structure and secretion. (2) The recombinant Ig molecules are processed by spleen APC and the epitopes that are released are presented to T-cells. (3) Site of integration influences efficiency of processing and presentation. (4) Elongation of two neighbouring loops reduces Ig secretion. Taken together, our present results indicate that IgG C(H)1 domains may be engineered to carry T-cell epitopes in loop structures between beta-strands, but not all loops may be equally suitable for this purpose.
