|1356-1||Mycobacterium bovis BCG vaccine as a stable recombinant vactor for induction of a humoral response against the B antigen of C.diphtheriae.|
|Autores:||Dilzamar Veloso do Nascimento Nascimento (UERJ - Faculdade de Ciências Médicas) ; Odir Antonio Dellagostin Dellagostin, O.a. (UFPEL - Centro de Biotecnologia / FIOCRUZ - Instituto Oswaldo Cruz) ; Geraldo Moura Batista Pereira Pereira, G.m.b. (UERJ - Faculdade de Ciências Médicas / FIOCRUZ - Instituto Oswaldo Cruz) ; Ana Luiza de Mattos-guaraldi Mattos-guaraldi,a.l. (UERJ - Faculdade de Ciências Médicas) ; Geraldo Rodrigues Garcia Armôa Armôa, G.r. (FIOCRUZ - Instituto Oswaldo Cruz) |
Diphtheria, the classical disease caused by Corynebacterium diphtheriae, is an acute communicable infection of the upper respiratory tract that can be fatal. Local and systemic manifestations are basically due to the action of the diphtheria toxin (DT). The diphtheria vaccine used worldwide is a toxoid obtained by detoxifying DT, is administered in combination with tetanus toxoid and pertussis whole cell vaccine (DTP), and has been shown to be very effective in the control of diphtheria. Although associated with high efficacy in the prevention of disease, the diphtheria vaccine may present some post vaccination effects such as toxicity and reactogenicity resulting from the presence of contaminants in the vaccine originated during the process of production and/or detoxification. Therefore, strategies to develop a less toxic and at the same time economically viable vaccine alternative are the subject of intense investigation worldwide. In this context, one option to solve this issue would be the development of a new vaccine based on the use of an attenuated bacterial vector engineered to release the protective diphtheria antigen in vivo like the Mycobacterium bovis BCG. In this study, the Moreau substrain of BCG used in Brazil as a live vaccine against human tuberculosis was genetically modified to carry and express the gene encoding the diphtheria toxin fragment B (DTB).
In our study the DNA sequence encoding the dtb gene of C. diphtheriae was successfully cloned into the bifunctional vector pUS977 for cytoplasmic expression in mycobacteria under the control of the pAN promoter. Our study showed that the M. bovis BCG vaccine strain transformed with the pUS977dtbPW8 construct can express the target DTB antigen stably both in vitro and in vivo and mice immunized with this rBCG can mount a specific humoral response against the fragment B of the C. diphthteria toxin.
Financial Support: Faculdade de Ciências Médicas (PGCM), Universidade do Estado do Rio de Janeiro, RJ, Brazil. Bio-Manguinhos/FIOCRUZ, PAPES II/FIOCRUZ, FAPERJ, CNPq and CAPES.
Palavras-chave: Recombinant BCG, Park Williams 8, dtb gene, pUS 977 vector, Promotor pAN