The genes encoding these proteins are located in RD2, a genomic region deleted in a number of more recent BCG strains, including M. bovis BCG Pasteur, but present in BCG Moreau [6, 7]. The low levels of MPB70 and MPB83 in M. bovis BCG Pasteur were also confirmed find more in our study. Their reduced expression is due to a point mutation in the translational start codon of the sigK gene , observed in many BCG strains, but absent in BCG Moreau. Immunologic studies have shown that both proteins induce cellular and humoral immune responses
in experimental models of infection and in natural infection in humans [68, 69]. MPB63 is a protein only found in species within the Mtb complex , mTOR inhibitor cancer shown to be immunodominant both in humans and animal models  and a promising candidate for serodiagnosis of active TB as well as for vaccine development. MPB63 was identified in four different spots (109,111,112 and 160), 2 of which (111 and 160) showed statistically significant differences in expression, with an increase of more than 3-fold in BCG Moreau
as compared to BCG Pasteur (Table 1 and Figure 5). These 4 protein spots are likely to represent isoforms, probably differing due to the presence of PTMs, known to cause changes in pI resulting in slightly different migration. Moreover, MPB63 contains an N-terminal signal sequence as predicted by the SignalP software, which was experimentally verified . The alanine-proline rich protein (Apa, Rv1860, BCG1896, spots 11, 12, 13 and 14) is known to present a high content of proline and carbohydrate
groups  that interferes with its migratory behavior in SDS-PAGE. Although we have not identified modifications such as glycosylation, Carbohydrate this protein displays a characteristic four-spot pattern (doublet of 2 horizontally dispersed spots) on 2DE  (Additional file 5, Figure S2). The isoforms of lowest molecular mass (spots 13 and 14) showed a statistically significant 3-fold increase in expression in BCG Moreau (Table 1 and Figure 5). This protein seems to be restricted to the Mtb complex and has been shown to be a target for immune recognition in animals immunized with live BCG . In addition to its high immunogenicity, it has also been described as a potential adhesin involved in the colonization of target cells . Its higher expression could contribute to an increase in the immunogenicity of BCG Moreau. Four proteins were found to be at least 2-fold more expressed in BCG Pasteur compared to Moreau: a peptidyl-prolyl cis-trans selleck chemicals isomerase (PPIaseA, Rv0009, BCG0009), the trigger factor (TF, Rv2462c, BCG2482c), Hsp65 (GroEL2, Rv0440, BCG0479) and Hsp70 (DnaK, Rv0350, BCG0389), all described as participating in protein folding and response to stress, among other functions.