ABSTRACT
Objective To characterize the immunogenicity and the induction of cross-reactive responses against Mycobacterium tuberculosis (M. tuberculosis) of a proteoliposome (PL) from Mycobacterium bovis Bacillus Calmette–Guérin (BCG) with and without alum hydroxide (AL) as adjuvant (PLBCG-AL and PLBCG, respectively) in BALB/c mice. Methods BALB/c mice were inoculated with phosphate buffer solution, BCG, PLBCG and PLBCG-AL. The humoral immunogenicity was determined by ELISA [immunoglobulin G (IgG), IgG1 and IgG2a] and the cellular immunogenicity was evaluated in vivo by delayed type hypersensitivity. The humoral cross-reactive response against M. tuberculosis was determined by Western blot. Results Sera from animals immunized with PLBCG-AL and PLBCG showed significant increase in specific total IgG and IgG1 antibodies and the presence of cross-reactive antibodies against M. tuberculosis antigens, which were more intense with the use of alum as adjuvant. Mice immunized with PLBCG and PLBCG-AL also showed a specific cellular response in vivo. Conclusions The cellular and humoral immunogenicity of PLBCG and the capacity to induce cross-reactive responses against M. tuberculosis is in agreement with the protective capacity previously demonstrated by this vaccine candidate and supports the continuation of its evaluation in further stages.
ABSTRACT
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-alpha-alpha'-o-trehalose [Ac[2]SGL] is specific for Mtb, and is not present in other mycobacterial species. The CD1b-Ac[2]SGL 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-Ac[2]SGL complexes
Methods: a synthetic human scFv phage antibody library was used to select phage-displayed antibody fragments that recognized CD1b-Ac[2]SGL using CD1btransfected THP-1 cells loaded with Ac[2]SGL
Results: one clone, D11- a single, light-variable domain [kappa] antibody [dAb[kappa]11]-showed high relative binding to the Ac[2]SGL-CD1b complex
Conclusion: a ligand recognizing the Ac[2]SGL- CD1b complex was obtained, which is a potential candidate to be further tested for diagnostic and therapeutic applications
ABSTRACT
Objective/background: The search for new vaccines more efficacious than bacille Calmette-Guerin for tuberculosis prevention is of paramount importance for the control of the disease. The expression of Mycobacterium tuberculosis antigens in Mycobacterium smegmatis is one of the current strategies for the development of new-generation vaccines against tuberculosis. The objective of this study was to evaluate the immunogenicity in mice of M. smegmatis expressing epitopes from Ag85B antigen
Methods: M. smegmatis expressing three T cell epitopes from M. tuberculosis Ag85B [P21, P26, and P53] was constructed [rMs064]. rMs064 was used to immunize BALB/C mice for immunogenicity evaluation. The present study investigates the capacity of rMs064 to induce specific cellular and humoral immune responses against the expressed epitopes. Cytokine production upon stimulation with Ag85B peptides and specific total immunoglobulin G and immunoglobulin G subclasses were determined
Results: The results showed a significant production of interleukin-12 and interleukin-23 when splenocytes were stimulated with P21, P26, and P53 peptides, and interferon-gamma after stimulation with P21 in animals immunized with rMs064 compared with controls. The total immunoglobulin G and its subclasses showed significant increases against the Ag85B epitapes in the sera of rMs064-immunized mice compared with the control groups
Conclusion: The results of this study support the future evaluation of rMs064 as a vaccine candidate against tuberculosis in challenge experiments
Subject(s)
Animals, Laboratory , Immunity, Humoral , Immunity, Cellular , Epitopes , Recombinant Fusion Proteins , Tuberculosis Vaccines , Tuberculosis , Antigens, Bacterial , MiceABSTRACT
Research, development, and production of vaccines are still highly dependent on the use of animal models in the various evaluation steps. Despite this fact, there are strong interests and ongoing efforts to reduce the use of animals in vaccine development. Tuberculosis vaccine development is one important example of the complexities involved in the use of animal models for the production of new vaccines. This review summarises some of the general aspects related with the use of animals in vaccine research and production, as well as achievements and challenges towards the rational use of animals, particularly in the case of tuberculosis vaccine development.