Background: Host-directed therapies are a comparatively new and promising method for
the treatment of tuberculosis. A variety of host pathways, vaccines and drugs have the potential to
provide novel adjunctive therapies for the treatment of tuberculosis. In this connection, we have
earlier reported the immunotherapeutic potential of N-formylated N-terminal peptide of glutamine
synthetase of Mycobacterim tuberculosis H37Rv (Mir SA and Sharma S, 2014). Now in the present
study, we investigated the immunotherapeutic effect of N-terminally formylated internal-peptide 'f-
MLLLPD' of mycobacterial glutamine synthetase (Rv2220) in mouse model of tuberculosis.
Methods: The N-terminally formylated peptide, f-MLLLPD was tested for its potential to generate
Reactive Oxygen Species (ROS) in murine neutrophils. Further, its therapeutic effect alone or in
combination with anti-tubercular drugs was evaluated in mouse model of tuberculosis.
Results: The f-MLLLPD peptide treatment alone and in combination with ATDs reduced the
bacterial load (indicated as colony forming units) in lungs of infected mice by 0.58 (p<0.01) and
2.92 (p<0.001) log10 units respectively and in their spleens by 0.46 (p<0.05) and 2.46 (p<0.001)
log10 units respectively. In addition, the observed histopathological results correlated well with the
Conclusion: The results of the current study show that f-MLLLPD peptide confers an additional
therapeutic efficacy to the anti-tuberculosis drugs.