The Antituberculosis Drug Pyrazinamide Affects the Course of Cutaneous Leishmaniasis In Vivo and Increases Activation of Macrophages and Dendritic Cells

Abstract

Antileishmanial therapy is suboptimal due to toxicity, high cost, and development of resistance to available drugs. Pyrazinamide (PZA) is a constituent of short-course tuberculosis chemotherapy. We investigated the effect of PZA on Leishmania major promastigote and amastigote survival. Promastigotes were more sensitive to the drug than amastigotes, with concentrations at which 50% of parasites were inhibited (MIC 50 ) of 16.1 and 8.2 M, respectively (48 h posttreatment). Moreover, 90% of amastigotes were eliminated at 120 h posttreatment, indicating that longer treatments will result in parasite elimination. Most strikingly, PZA treatment of infected C57BL/6 mice resulted in protection against disease and in a 100-fold reduction in the parasite burden. PZA treatment of J774 cells and bone marrow-derived dendritic cells and macrophages increased interleukin 12, tumor necrosis factor alpha, and activation marker expression, as well as nitric oxide production, suggesting that PZA enhances effective immune responses against the parasite. PZA treatment also activates dendritic cells deficient in Toll-like receptor 2 and 4 expression to initiate a proinflammatory response, confirming that the immunostimulatory effect of PZA is directly caused by the drug and is independent of Toll-like receptor stimulation. These results not only are strongly indicative of the promise of PZA as an alternative antileishmanial chemotherapy but also suggest that PZA causes collateral immunostimulation, a phenomenon that has never been reported for this drug.

Evaluation of Standard Chemotherapy in the Guinea Pig Model of Tuberculosis

“…Despite the apparent dampening of acquired immunity, we observed significant increases in the levels of the TH1-associated cytokines IFN-␥, IL-12, and TNF-␣ using RT-PCR. A recent report demonstrated that PZA treatment of murine cutaneous leishmaniasis results in a 100-fold reduction in the parasite burden and increased macrophage activation and TH1 cytokine levels (34). It is apparent from the findings of our studies that the cessation of chemotherapy, including PZA therapy, resulted in a decline in TH1 immunity, supporting the findings of that recent study.…”

Intestinal Parasite Co-infection among Pulmonary Tuberculosis Cases without Human Immunodeficiency Virus Infection in a Rural County in China

“…14 Many studies have shown that one or more of these drugs had a significant in vivo effect against Leishmania spp., 31,32 Plasmodium spp., 33,34 Toxoplasma gondii, 35 Wuchereria bancrofti, 36 Brugia malayi,…”

Inhaled Pyrazinoic Acid Esters for the Treatment of Tuberculosis

“…Further, PZA is the only antitubercular agent known to efficiently diffuse into the caseum of lung granulomas (16). PZA is also reported to modulate host immune responses (17,18). An immunomodulatory effect of PZA might be an additional factor contributing to TB treatment success.…”