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Drug resistant clinical isolates of Mycobacterium tuberculosis from different genotypes exhibit differential host responses in THP-1 cells.

Chakraborty P, Kulkarni S, Rajan R, Sainis K - PLoS ONE (2013)

Bottom Line: EAI-5 strain from ancient lineage 1, induced higher proinflammatory responses, higher apoptosis and moderate intracellular growth compared to other strains, in contrast, for Beijing strain of modern lineage 2, all three parameters were lowest among the clinical isolates.Thus, these profiles were specific to their respective lineages and/or genotypes and independent of their drug resistance status.Further, a positive correlation, among TNF-α, IL-1β, IL-6 and IL-12 induced in infected THP-1 cells was demonstrated.

View Article: PubMed Central - PubMed

Affiliation: Radiation Medicine Centre, Bio-Medical Group, Bhabha Atomic Research Centre, Mumbai, India.

ABSTRACT
Mycobacterium tuberculosis (MTB) persistently infects and survives within the host macrophages. Substantial genotypic variation exists among MTB strains which correlate with their interactions with the host. The present study was designed to establish a correlation, if any, between infection and induction of innate immune response by genetically diverse drug resistant MTB isolates from India. For this purpose, three clinical isolates from ancient and modern lineages, along with H37Ra and H37Rv were evaluated for intracellular growth, phagocytic index, induction of proinflammatory cytokines and apoptosis following infection in THP-1 cell line. A wide variation in the induction of cytokines was revealed subsequent to infection with different strains. EAI-5 strain from ancient lineage 1, induced higher proinflammatory responses, higher apoptosis and moderate intracellular growth compared to other strains, in contrast, for Beijing strain of modern lineage 2, all three parameters were lowest among the clinical isolates. Further, the responses induced by LAM-6 from modern lineage 4 were at a moderate level, similar to the laboratory strain H37Rv which also belongs to lineage 4. Thus, these profiles were specific to their respective lineages and/or genotypes and independent of their drug resistance status. Further, a positive correlation, among TNF-α, IL-1β, IL-6 and IL-12 induced in infected THP-1 cells was demonstrated. In addition, induction of all pro-inflammatory cytokines correlated well with the host cell apoptosis. A positive correlation was observed between phagocytic index in the category of '>10 bacilli/cell' and induction of apoptosis, only for virulent strains, indicating that initial accumulation of MTB strains inside the host cell may be an important determining factor for different innate responses.

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Phagocytosis of different strains of MTB by THP-1 cells.The representative photographs show THP-1 cells infected with MTB and stained with auramine-KMnO4 after 4 hours of infection, seen under UV light (Olympus, Tokyo) (A) at high magnification (×1000) and (B) low magnification respectively (×400). (C) Phagocytic index was categorized into 1–5 bacilli, 6–10 bacilli and >10 bacilli per cell. Each bar represents the mean ± SD for pooled values from five independent experiments.
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pone-0062966-g001: Phagocytosis of different strains of MTB by THP-1 cells.The representative photographs show THP-1 cells infected with MTB and stained with auramine-KMnO4 after 4 hours of infection, seen under UV light (Olympus, Tokyo) (A) at high magnification (×1000) and (B) low magnification respectively (×400). (C) Phagocytic index was categorized into 1–5 bacilli, 6–10 bacilli and >10 bacilli per cell. Each bar represents the mean ± SD for pooled values from five independent experiments.

Mentions: The extent of infection by all MTB strains in THP-1 cells was scored on the basis of phagocytic index using phenolic auramine staining (Fig. 1A and 1B). All the strains showed comparable infectivity in THP-1 cells (65% to 70% after four hours of infection). However, when the cells showing phagocytosis were divided into three different groups viz. 1–5, 6–10 and greater than 10 bacilli per cell, it was found that significantly higher percentage of THP-1 cells infected with H37Ra, showed higher accumulation of bacteria i.e. 24±7% cells in the category ‘>10 bacilli/cell’ than those infected with either Beijing (10±3%) or LAM (15±4%) strains. The percentage of infected macrophages in ‘1–5 bacilli/cell’ category was higher compared to ‘6–10′ and ‘>10 bacilli/cell’ categories for all the strains (Fig. 1C).


Drug resistant clinical isolates of Mycobacterium tuberculosis from different genotypes exhibit differential host responses in THP-1 cells.

Chakraborty P, Kulkarni S, Rajan R, Sainis K - PLoS ONE (2013)

Phagocytosis of different strains of MTB by THP-1 cells.The representative photographs show THP-1 cells infected with MTB and stained with auramine-KMnO4 after 4 hours of infection, seen under UV light (Olympus, Tokyo) (A) at high magnification (×1000) and (B) low magnification respectively (×400). (C) Phagocytic index was categorized into 1–5 bacilli, 6–10 bacilli and >10 bacilli per cell. Each bar represents the mean ± SD for pooled values from five independent experiments.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3646887&req=5

pone-0062966-g001: Phagocytosis of different strains of MTB by THP-1 cells.The representative photographs show THP-1 cells infected with MTB and stained with auramine-KMnO4 after 4 hours of infection, seen under UV light (Olympus, Tokyo) (A) at high magnification (×1000) and (B) low magnification respectively (×400). (C) Phagocytic index was categorized into 1–5 bacilli, 6–10 bacilli and >10 bacilli per cell. Each bar represents the mean ± SD for pooled values from five independent experiments.
Mentions: The extent of infection by all MTB strains in THP-1 cells was scored on the basis of phagocytic index using phenolic auramine staining (Fig. 1A and 1B). All the strains showed comparable infectivity in THP-1 cells (65% to 70% after four hours of infection). However, when the cells showing phagocytosis were divided into three different groups viz. 1–5, 6–10 and greater than 10 bacilli per cell, it was found that significantly higher percentage of THP-1 cells infected with H37Ra, showed higher accumulation of bacteria i.e. 24±7% cells in the category ‘>10 bacilli/cell’ than those infected with either Beijing (10±3%) or LAM (15±4%) strains. The percentage of infected macrophages in ‘1–5 bacilli/cell’ category was higher compared to ‘6–10′ and ‘>10 bacilli/cell’ categories for all the strains (Fig. 1C).

Bottom Line: EAI-5 strain from ancient lineage 1, induced higher proinflammatory responses, higher apoptosis and moderate intracellular growth compared to other strains, in contrast, for Beijing strain of modern lineage 2, all three parameters were lowest among the clinical isolates.Thus, these profiles were specific to their respective lineages and/or genotypes and independent of their drug resistance status.Further, a positive correlation, among TNF-α, IL-1β, IL-6 and IL-12 induced in infected THP-1 cells was demonstrated.

View Article: PubMed Central - PubMed

Affiliation: Radiation Medicine Centre, Bio-Medical Group, Bhabha Atomic Research Centre, Mumbai, India.

ABSTRACT
Mycobacterium tuberculosis (MTB) persistently infects and survives within the host macrophages. Substantial genotypic variation exists among MTB strains which correlate with their interactions with the host. The present study was designed to establish a correlation, if any, between infection and induction of innate immune response by genetically diverse drug resistant MTB isolates from India. For this purpose, three clinical isolates from ancient and modern lineages, along with H37Ra and H37Rv were evaluated for intracellular growth, phagocytic index, induction of proinflammatory cytokines and apoptosis following infection in THP-1 cell line. A wide variation in the induction of cytokines was revealed subsequent to infection with different strains. EAI-5 strain from ancient lineage 1, induced higher proinflammatory responses, higher apoptosis and moderate intracellular growth compared to other strains, in contrast, for Beijing strain of modern lineage 2, all three parameters were lowest among the clinical isolates. Further, the responses induced by LAM-6 from modern lineage 4 were at a moderate level, similar to the laboratory strain H37Rv which also belongs to lineage 4. Thus, these profiles were specific to their respective lineages and/or genotypes and independent of their drug resistance status. Further, a positive correlation, among TNF-α, IL-1β, IL-6 and IL-12 induced in infected THP-1 cells was demonstrated. In addition, induction of all pro-inflammatory cytokines correlated well with the host cell apoptosis. A positive correlation was observed between phagocytic index in the category of '>10 bacilli/cell' and induction of apoptosis, only for virulent strains, indicating that initial accumulation of MTB strains inside the host cell may be an important determining factor for different innate responses.

Show MeSH
Related in: MedlinePlus