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Stimulation through CD40 and TLR-4 Is an Effective Host Directed Therapy against Mycobacterium tuberculosis

View Article: PubMed Central - PubMed

ABSTRACT

Tuberculosis (TB) is the leading cause of morbidity and mortality among all infectious diseases. Failure of Bacillus Calmette Guerin as a vaccine and serious side-effects and toxicity due to long-term TB drug regime are the major hurdles associated with TB control. The problem is further compounded by the emergence of drug-resistance strains of Mycobacterium tuberculosis (Mtb). Consequently, it demands a serious attempt to explore safer and superior treatment approaches. Recently, an improved understanding of host–pathogen interaction has opened up new avenues for immunotherapy for treating TB. Although, dendritic cells (DCs) show a profound role in generating immunity against Mtb, their immunotherapeutic potential needs to be precisely investigated in controlling TB. Here, we have devised an approach of bolstering DCs efficacy against Mtb by delivering signals through CD40 and TLR-4 molecules. We found that DCs triggered through CD40 and TLR-4 showed increased secretion of IL-12, IL-6, and TNF-α. It also augmented autophagy. Interestingly, CD40 and TLR-4 stimulation along with the suboptimal dose of anti-TB drugs significantly fortified their efficacy to kill Mtb. Importantly, animals treated with the agonists of CD40 and TLR-4 boosted Th1 and Th17 immunity. Furthermore, it amplified the pool of memory CD4 T cells as well as CD8 T cells. Furthermore, substantial reduction in the bacterial burden in the lungs was observed. Notably, this adjunct therapy employing immunomodulators and chemotherapy can reinvigorate host immunity suppressed due to drugs and Mtb. Moreover, it would strengthen the potency of drugs in curing TB.

No MeSH data available.


Related in: MedlinePlus

Immunomodulation through C40.T4 reduces the bacterial burden in the lungs of Mtb-challenged mice and enhances the potency of isoniazid. (A) Mice infected with Mtb were immunized with C40.T4. Later, animals were sacrificed and mycobacterial load in the lungs was enumerated by CFUs plating; (B) Photomicrographs (40×) of H & E stained lung sections. (C) CD4 and CD8 T cells were purified from C40.T4 treated and Mtb-challenged mice. Later, CD4 or CD8 T cells were adoptively transferred into sub-lethally irradiated mice. After 12 h, mice were aerosol challenged with Mtb. The bacterial burden in the lungs was enumerated on 15 days by CFUs plating. Labeling of “x” axis signifies CD4 or CD8: adoptive transfer of either CD4 or CD8 T cells isolated from Mtb-challenged mice; C40.T4.CD4 or C40.T4.CD8: adoptive transfer of either CD4 or CD8 T cells isolated from Mtb-challenged and C40.T4-treated mice. (D) Animals infected with Mtb were administered with C40.T4 and two doses of INH (INH5: 5 mg/kg bwt, INH25: 25 mg/kg bwt of mouse). Later, mice were sacrificed and mycobacterial load was enumerated in the lungs by CFUs plating. Data represented as mean ± SEM are from two independent experiments with (n = 4mice/group). Control groups of mice were administered PBS, CD40A, TLR-4L. “IC”: isotype control. “*,” “**,” and “***” indicate p < 0.05, p < 0.01, and p < 0.001, respectively.
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Figure 8: Immunomodulation through C40.T4 reduces the bacterial burden in the lungs of Mtb-challenged mice and enhances the potency of isoniazid. (A) Mice infected with Mtb were immunized with C40.T4. Later, animals were sacrificed and mycobacterial load in the lungs was enumerated by CFUs plating; (B) Photomicrographs (40×) of H & E stained lung sections. (C) CD4 and CD8 T cells were purified from C40.T4 treated and Mtb-challenged mice. Later, CD4 or CD8 T cells were adoptively transferred into sub-lethally irradiated mice. After 12 h, mice were aerosol challenged with Mtb. The bacterial burden in the lungs was enumerated on 15 days by CFUs plating. Labeling of “x” axis signifies CD4 or CD8: adoptive transfer of either CD4 or CD8 T cells isolated from Mtb-challenged mice; C40.T4.CD4 or C40.T4.CD8: adoptive transfer of either CD4 or CD8 T cells isolated from Mtb-challenged and C40.T4-treated mice. (D) Animals infected with Mtb were administered with C40.T4 and two doses of INH (INH5: 5 mg/kg bwt, INH25: 25 mg/kg bwt of mouse). Later, mice were sacrificed and mycobacterial load was enumerated in the lungs by CFUs plating. Data represented as mean ± SEM are from two independent experiments with (n = 4mice/group). Control groups of mice were administered PBS, CD40A, TLR-4L. “IC”: isotype control. “*,” “**,” and “***” indicate p < 0.05, p < 0.01, and p < 0.001, respectively.

Mentions: Next, we monitored the CFU burden in the lungs of C40.T4 treated mice. We observed significant (p < 0.01) decline in the mycobacterial burden compared to control mice treated with PBS, TLR-4L and CD40A (Figure 8A). Furthermore, the data were validated by histopathology samples. We observed that C40.T4 treated lungs showed less granulomatous lesions. The lungs were less consolidated with more normal alveolar structures. The number of granulomas were decreased in the lungs of C40.T4 immunized mice, as compared to placebo control (Figure 8B). These experiments showed the potential of C40.T4 immunotherapy in boosting the immunity of the Mtb-infected animals along with reduction in the bacterial load.


Stimulation through CD40 and TLR-4 Is an Effective Host Directed Therapy against Mycobacterium tuberculosis
Immunomodulation through C40.T4 reduces the bacterial burden in the lungs of Mtb-challenged mice and enhances the potency of isoniazid. (A) Mice infected with Mtb were immunized with C40.T4. Later, animals were sacrificed and mycobacterial load in the lungs was enumerated by CFUs plating; (B) Photomicrographs (40×) of H & E stained lung sections. (C) CD4 and CD8 T cells were purified from C40.T4 treated and Mtb-challenged mice. Later, CD4 or CD8 T cells were adoptively transferred into sub-lethally irradiated mice. After 12 h, mice were aerosol challenged with Mtb. The bacterial burden in the lungs was enumerated on 15 days by CFUs plating. Labeling of “x” axis signifies CD4 or CD8: adoptive transfer of either CD4 or CD8 T cells isolated from Mtb-challenged mice; C40.T4.CD4 or C40.T4.CD8: adoptive transfer of either CD4 or CD8 T cells isolated from Mtb-challenged and C40.T4-treated mice. (D) Animals infected with Mtb were administered with C40.T4 and two doses of INH (INH5: 5 mg/kg bwt, INH25: 25 mg/kg bwt of mouse). Later, mice were sacrificed and mycobacterial load was enumerated in the lungs by CFUs plating. Data represented as mean ± SEM are from two independent experiments with (n = 4mice/group). Control groups of mice were administered PBS, CD40A, TLR-4L. “IC”: isotype control. “*,” “**,” and “***” indicate p < 0.05, p < 0.01, and p < 0.001, respectively.
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Figure 8: Immunomodulation through C40.T4 reduces the bacterial burden in the lungs of Mtb-challenged mice and enhances the potency of isoniazid. (A) Mice infected with Mtb were immunized with C40.T4. Later, animals were sacrificed and mycobacterial load in the lungs was enumerated by CFUs plating; (B) Photomicrographs (40×) of H & E stained lung sections. (C) CD4 and CD8 T cells were purified from C40.T4 treated and Mtb-challenged mice. Later, CD4 or CD8 T cells were adoptively transferred into sub-lethally irradiated mice. After 12 h, mice were aerosol challenged with Mtb. The bacterial burden in the lungs was enumerated on 15 days by CFUs plating. Labeling of “x” axis signifies CD4 or CD8: adoptive transfer of either CD4 or CD8 T cells isolated from Mtb-challenged mice; C40.T4.CD4 or C40.T4.CD8: adoptive transfer of either CD4 or CD8 T cells isolated from Mtb-challenged and C40.T4-treated mice. (D) Animals infected with Mtb were administered with C40.T4 and two doses of INH (INH5: 5 mg/kg bwt, INH25: 25 mg/kg bwt of mouse). Later, mice were sacrificed and mycobacterial load was enumerated in the lungs by CFUs plating. Data represented as mean ± SEM are from two independent experiments with (n = 4mice/group). Control groups of mice were administered PBS, CD40A, TLR-4L. “IC”: isotype control. “*,” “**,” and “***” indicate p < 0.05, p < 0.01, and p < 0.001, respectively.
Mentions: Next, we monitored the CFU burden in the lungs of C40.T4 treated mice. We observed significant (p < 0.01) decline in the mycobacterial burden compared to control mice treated with PBS, TLR-4L and CD40A (Figure 8A). Furthermore, the data were validated by histopathology samples. We observed that C40.T4 treated lungs showed less granulomatous lesions. The lungs were less consolidated with more normal alveolar structures. The number of granulomas were decreased in the lungs of C40.T4 immunized mice, as compared to placebo control (Figure 8B). These experiments showed the potential of C40.T4 immunotherapy in boosting the immunity of the Mtb-infected animals along with reduction in the bacterial load.

View Article: PubMed Central - PubMed

ABSTRACT

Tuberculosis (TB) is the leading cause of morbidity and mortality among all infectious diseases. Failure of Bacillus Calmette Guerin as a vaccine and serious side-effects and toxicity due to long-term TB drug regime are the major hurdles associated with TB control. The problem is further compounded by the emergence of drug-resistance strains of Mycobacterium tuberculosis (Mtb). Consequently, it demands a serious attempt to explore safer and superior treatment approaches. Recently, an improved understanding of host&ndash;pathogen interaction has opened up new avenues for immunotherapy for treating TB. Although, dendritic cells (DCs) show a profound role in generating immunity against Mtb, their immunotherapeutic potential needs to be precisely investigated in controlling TB. Here, we have devised an approach of bolstering DCs efficacy against Mtb by delivering signals through CD40 and TLR-4 molecules. We found that DCs triggered through CD40 and TLR-4 showed increased secretion of IL-12, IL-6, and TNF-&alpha;. It also augmented autophagy. Interestingly, CD40 and TLR-4 stimulation along with the suboptimal dose of anti-TB drugs significantly fortified their efficacy to kill Mtb. Importantly, animals treated with the agonists of CD40 and TLR-4 boosted Th1 and Th17 immunity. Furthermore, it amplified the pool of memory CD4 T cells as well as CD8 T cells. Furthermore, substantial reduction in the bacterial burden in the lungs was observed. Notably, this adjunct therapy employing immunomodulators and chemotherapy can reinvigorate host immunity suppressed due to drugs and Mtb. Moreover, it would strengthen the potency of drugs in curing TB.

No MeSH data available.


Related in: MedlinePlus