RESUMO
OBJECTIVE/BACKGROUND: The development of new tools capable of targeting Mycobacterium tuberculosis (Mtb)-infected cells have potential applications in diagnosis, treatment, and prevention of tuberculosis. In Mtb-infected cells, CD1b molecules present Mtb lipids to the immune system (Mtb lipid-CD1b complexes). Because of the lack of CD1b polymorphism, specific Mtb lipid-CD1b complexes could be considered as universal Mtb infection markers. 2-Stearoyl-3-hydroxyphthioceranoyl-2'-sulfate-α-α'-d-trehalose (Ac2SGL) is specific for Mtb, and is not present in other mycobacterial species. The CD1b-Ac2SGL complexes are expressed on the surface of human cells infected with Mtb. The aim of this study was to generate ligands capable of binding these CD1b-Ac2SGL complexes. METHODS: A synthetic human scFv phage antibody library was used to select phage-displayed antibody fragments that recognized CD1b-Ac2SGL using CD1b-transfected THP-1 cells loaded with Ac2SGL. RESULTS: One clone, D11-a single, light-variable domain (kappa) antibody (dAbκ11)-showed high relative binding to the Ac2SGL-CD1b complex. CONCLUSION: A ligand recognizing the Ac2SGL-CD1b complex was obtained, which is a potential candidate to be further tested for diagnostic and therapeutic applications.
Assuntos
Anticorpos Antibacterianos/imunologia , Antígenos CD1/imunologia , Glicolipídeos/imunologia , Mycobacterium tuberculosis/imunologia , Anticorpos de Cadeia Única/genética , Tuberculose/imunologia , Anticorpos Antibacterianos/genética , Antígenos CD1/genética , Bacteriófagos/genética , Bacteriófagos/metabolismo , Expressão Gênica , Humanos , Mycobacterium tuberculosis/genética , Anticorpos de Cadeia Única/imunologia , Tuberculose/microbiologiaRESUMO
The development of molecules specific for M. tuberculosis-infected cells has important implications, as these tools may facilitate understanding of the mechanisms regulating host pathogen interactions in vivo. In addition, development of new tools capable to targeting M. tuberculosis-infected cells may have potential applications to diagnosis, treatment, and prevention of tuberculosis (TB). Due to the lack of CD1b polymorphism, M. tuberculosis lipid-CD1b complexes could be considered as universal tuberculosis infection markers. The aim of the present study was to display on the PIII surface protein of m13 phage, a human αß single-chain T-cell receptor molecule specific for CD1b:2-stearoyl-3-hydroxyphthioceranoyl-2´-sulfate-α-α´-D-trehalose (Ac2SGL) which is a complex presented by human cells infected with M. tuberculosis. The results showed the pIII fusion particle was successfully displayed on the phage surface. The study of the recognition of the recombinant phage in ELISA and immunohistochemistry showed the recognition of CD1b:Ac2SGL complexes and cells in human lung tissue from a tuberculosis patient respectively, suggesting the specific recognition of the lipid-CD1b complex.