BCG, the only available vaccine against tuberculosis affords a variable protection which
wanes with time. In this study we have analyzed and compared the proteins which are expressed differentially
during broth-culture and intraphagosomal growth of M.bovis BCG. Eight proteins which
showed increased expression during the intraphagosomal growth were identified by MALDI-TOF/MS.
These were - a precursor of alanine and proline-rich secreted protein apa, isoforms of malate dehydrogenase,
large subunit alpha (Alpha-ETF) of electron transfer flavoprotein, immunogenic protein MPB64 precursor,
UPF0036 protein, and two proteins with unknown function. Based on these findings we speculate that higher expression
of these proteins has a probable role in intracellular survival, adaptation and/or immunoprotective effect of BCG. Further,
these proteins might also be used as gene expression markers for endosome trafficking events of BCG.