Phenotypic modulation in Mycobacterium tuberculosis infected neutrophil during tuberculosis.
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Date
2009-08
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Abstract
Background & objectives: Polymorphonuclear leucocytes (PMN) or neutrophils infiltrate to the
inflammatory sites and phagocytose mycobacteria thereby inhibiting the bacillary spread initially
until the accumulated macrophages get activated. The present study was carried out to highlight the
interaction of neutrophils with the two clinical isolates (S7 and S10) of Mycobacterium tuberculosis and
the subsequent morphological changes.
Methods: Dextran purified neutrophils from normal and TB patients infected with M. tuberculosis
isolates were cultured for 3 and 18 h time points. At the end of termination, the cell surface expression
of CD16, CD69, CXCR2 and induction of apoptosis were analyzed using flow cytometry. Cytokines and
chemokines were estimated in supernatants by ELISA.
Results: All infected PMN showed decrease in CD16 at both time points in normals while at 18 h in TB
group. Interestingly, CD69 expression was significantly high at early time point in TB-PMN compared
to normals. The high expression of CXCR2 was sustained in infected TB-PMN at both the time points.
S7 and S10 infected neutrophils showed high phagocytic indices compared to H37Rv in both the groups.
A significant increase in apoptosis was observed at both the time points in infected TB-PMN but only
at 18 h in normals. Increased pro-inflammatory cytokine (TNF-α) and chemokine (IL-8) response was
observed in infected neutrophils at 3 h in both the groups.
Interpretation & conclusions: This study demonstrates the varying degree of modulation of neutrophil
functions in both the groups. TB-PMN was more competent in amplifying the innate immune response
and conferring protection at the early phase of infection. However, the response was not strain specific in either of these groups.
Description
Keywords
apoptosis, chemokines, cytokines, Mycobacterium tuberculosis, neutrophils
Citation
Pokkali Supriya, Rajavelu Priya, Sudhakar R, Das Sulochana D. Phenotypic modulation in Mycobacterium tuberculosis infected neutrophil during tuberculosis. Indian Journal of Medical Research. 2009 Aug; 130(2): 185-192.