Monoclonal antibodies to Mycobacterium tuberculosis CDC 1551 reveal subcellular localization of MPT51

Abstract

Mycobacterium tuberculosis CDC 1551, a highly immunogenic outbreak strain, previously reported to have unique surface distribution of capsular polysaccharide, was used to generate novel monoclonal antibodies (mAbs) to surface mycobacterial targets. Two Immunoglobulin G1 (IgG1) mAbs, 16a1 and 16a6 were generated. The mAbs originated from the same B cell, bound strongly to whole cell M. tuberculosis CDC1551 and to its cell wall, membrane and cytosol fractions recognizing a 90 kDa protein. Immunoprecipitation using mAb 16a1 isolated a protein with amino acid peptide sequences matching MPT51 from the cytosol. This immunogenic protein of unknown function, was previously reported only in culture filtrates of M. tuberculosis. Our findings suggest for the first time that this protein is found within the M. tuberculosis cell.

Antibodies and tuberculosis

“…Another surface-binding murine mAb against MPT51 is able to agglutinate cultures of the pathogenic strain CDC1551 at a concentration of 100ug/ml in comparison to a control anti- M.tb mAb that did not bind the surface of this strain [107]. This corroborates findings that antibodies can interact with inhaled mycobacteria in the mucosa, and may be a mechanism whereby antibodies prevent entry into host cells.…”

“…MAb against MPT51 agglutinates cultures of M.tb CDC1551 and may show immune exclusion mechanism [107]…”

Analysis of the Secretome and Identification of Novel Constituents from Culture Filtrate of Bacillus Calmette-Guérin Using High-resolution Mass Spectrometry

“…FbpD, also known as the secreted MPT51/ MPB51 antigen, can induce a high level of antigen-specific CD8ϩ T-cell response (49). It is interesting that this immunogenic protein was previously reported in the CF and also within the cell (50).…”

Dormancy models for <italic>Mycobacterium tuberculosis</italic>: A minireview

“…Water bath sonication is used to disintegrate clumps, followed by homogenization of samples by re-suspending harvested bacteria in fresh broth containing the detergent Tween-80 to inhibit further clumping. However, the effectiveness of sonication in disrupting clumps of mycobacteria is variable ( Al-Sayyed et al. , 2007 ; Stokes et al.…”

“…, 2007 ; Stokes et al. , 2004 ), and prolonged sonication is not recommended because of its adverse effects on the viability of mycobacteria ( Al-Sayyed et al , 2007 ; Stokes et al , 2004 ). Other mechanical measures that may help overcome the high variability in colony count include agitation with glass beads.…”