T‐ and B‐Cell Epitopes in the Secreted Mycobacterium bovis Antigen MPB70 in Mice

Abstract

MPB70 is a soluble secreted protein highly expressed in Mycobacterium bovis and strains of bacille Calmette±Gue Ârin (BCG); as such, it is a candidate for subunit and DNA vaccines against tuberculosis. MPB70 was screened for T-cell epitopes in four different inbred mouse strains. Major histocompatibility complex (MHC) H-2 b -expressing mice (C57BL/6) secreted interferon-g (IFN-g) after stimulation with peptides from the regions 1±20, 41±50, 81±110, 121±150 and 161±193 of the MPB70 sequence. H-2 db mouse (B6D2) splenocytes secreted IFN-g after stimulation with some of the same peptides, whereas H-2 d mice (BALB/c and DBA/2) did not secrete IFN-g upon stimulation with the peptides. Sera from H-2 db mice immunized with native MPB70 in incomplete Freund's adjuvant (IFA), mpb70 DNA or live BCG Moreau were found to contain antibodies against the native MPB70 antigen. H-2 db mice immunized with native MPB70 in IFA exhibited high titres of peptide-reactive immunoglobulin G1 (IgG1) antibodies, whereas DNA-immunized mice reacted with IgG2a antibodies against some of the same peptides. As some of the epitopes recognized by mouse T and B cells have previously been found to stimulate immune responses in humans, cattle and rabbits, we conclude that these epitopes may be good general epitopes for the stimulation of T-and B-cell responses and candidates for a DNA vaccine with a broad applicability.

Reduced expression of antigenic proteins MPB70 and MPB83 in Mycobacterium bovis BCG strains due to a start codon mutation in sigK

“…, 1987; Fifis et al ., 1994; Roche et al ., 1994; Harboe et al ., 1995; Wiker et al ., 1996; Vordermeier et al ., 2000; Lyashchenko et al ., 2001). Based on these observations, both MBP70 and MPB83 have been developed as candidates for novel TB vaccine development (Chambers et al ., 2000; Morris et al ., 2000; Al Attiyah et al ., 2003; Tollefsen et al ., 2003; Xue et al ., 2004). As extracellular antigens have consistently been implicated in the induction of a protective immune response against M. tuberculosis , it is remarkable that all BCG strains are unable to produce the antigenic proteins ESAT‐6 and CFP‐10 (lost with the RD1 deletion of 1908–1921), while strains obtained after 1927–1931 are also deficient (through the deletion of RD2) in the proteins MPB64 (Harboe et al ., 1986; Li et al ., 1993) and CFP‐21 (Mahairas et al ., 1996; Weldingh et al ., 1998; Weldingh and Andersen, 1999) and functionally deficient in production of MPB70 and MPB83 via the sigK mutation described here.…”

DNA Injection in Combination with Electroporation: a Novel Method for Vaccination of Farmed Ruminants

“…Firstly, different species and even different breeds of the same species can develop diverse immune responses after vaccination with the same antigens. For example, it has been reported that mice of H-2 b and H2 d haplotype can develop Th1and Th2-type responses, respectively, after BCG vaccination [34,35]. Secondly, the balance between cellular and humoral immune responses induced following vaccination or infection could also be influenced by the nature of the antigens.…”

Immunity towards tuberculosis infection: A review

“…In order to fight against the TB, the development of the mediated immune response by cytotoxic Th1 CD4+ and T CD8+ of the IFN- (Tollefsen et al, 2003) is essential. The development of anergy and reduction in the number of T cells CD4+ in patients with viral diseases contribute to the susceptibility to TB (Bouchonnet et al, 2002).…”