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Objective: Leishmaniasis is of public health problems, especially in endemic areas. The activation of macrophages, as the main host of leishmania and promotion of the TH1 immune responses, are the main goal of im-munotherapy methods. Recently, the immunomodulatory role of mesenchymal stem cells (MSCs) in infectious disease has been considered. Different in vitro studies demonstrated the immunostimulatory effect of MSCs on macrophages in response to L.major. In this study, the effect of MSCs on cutaneous leishmaniasis in BALB/c mice was assessed., Materials and Methods: To do this experimental research, BALB/c mice infected with L. major that was followed by multiple subcutaneous injections of MSCs at infection site at different intervals. Footpad thickness, spleen parasite burden, lymph node, and spleen cytokine production were measured to determine the efficacy of cell therapy., Results: Significant (P<0.05) reduction in footpad thickness and delayed wound formation was observed in MSCs treated group. The spleen of the MSCs-treated group indicated a two-fold reduction in parasite burden compared with non-treated infected mice. In addition, nitric oxide (NO), interleukin-10 (IL-10), and tumor necrosis factor-alpha (TNF-α) production of lymph node isolated cells and splenocytes changed to the benefit of macrophage activation in response to L. major in MSCs treated group. A two-fold increase in interferon-gamma (IFN-γ) production in the lymph node was determined in the MSCs-treated group., Conclusion: Although MSCs therapy could not clear the parasite, the results confirm the ability of MSCs to enhance immune responses against leishmania by induction of inflammatory responses and slowing down the spread of parasites. However, further studies needed to improve the efficacy of this method and provide a therapeutic protocol., Competing Interests: There is no conflict of interest in this study., (Copyright© by Royan Institute. All rights reserved.)

Objective: Immunotoxins (ITs) have been developed for the treatment of cancer, and comprise of antibodies linked to toxins. Also vascular endothelial growth factor (VEGF) plays a key role in tumor angiogenesis, and the blockade of VEGF receptor-2 (VEGFR2) inhibits angiogenesis and tumor growth. The aim of this study was to produce anti-VEGFR2/rPE (Pseudomonas exotoxin) 38 IT to test its cytotoxic activity and mechanism of action., Materials and Methods: In this basic research and experimental study, at first, DNA that encodes recombinant PE38 protein was inductively expressed in Escherichia coli (E.coli) and purified by nickel-sepharose chromatography and further analyzed by western blot. Then, for production of IT, rPE38 was chemically conjugated to anti- VEGFR2. The cytotoxicity response of IT treatment was evaluated by 3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide (MTT) test in Human Umbilical Vein Endothelial Cell (HUVEC) and Michigan Cancer Foundation-7 (MCF-7) (VEGFR2+) cell lines. The mechanism of IT cytotoxicity was observed by Annexin V staining and flow cytometry. Continuous variables were compared with the analysis of variance (ANOVA; for all groups). P values less than 0.05 were considered statistically significant., Results: SDS-PAGE showed 98% purity of rPE38 and IT. In vitro dose-dependent cytotoxicity assay demonstrated that anti-VEGFR2/PE38 is toxic to VEGFR2-positive cells. IT treatment significantly inhibited proliferation of HUVEC and MCF-7 in a VEGFR2-specific manner as compared with the control groups (p<0.05). Flow cytometry showed that the mechanism of IT induced cell death is mediated by apoptosis., Conclusion: IT treatment also caused remarkable synergistic cytotoxicity characterized by decreased cell viability, and an increased apoptotic index by both anti-VEGFR2 and PE38. Thus these results raise the possibility of using anti-VEGFR2/PE38 IT for cancer therapy because nearly all tumors induce local angiogenesis with high VEGFR expression.

Objective: Macrophages influence their environment and surrounding immune cells as soon as stimulators affect them. Different sources of macrophages induce different reactions in their neighboring immune cells,which result in non-uniform immunologic outcomes. In this experimental research, we compare the behavior of peritoneal macrophages to lipopolysaccharide (LPS) stimulation from BALB/cmice as an indicator of a type 2 immune response and from C57BL/6 mice as an indicator of a type 1 immune response., Materials and Methods: In this experimental study, peritoneal macrophages prepared from thioglycolate stimulated BALB/c and C57BL/6 micewere treated with 1µg/ml LPS. At different time points after LPS treatment, nitric oxide (NO), interferon gamma (IFN-λ), interleukin 4 (IL-4),transforming growth factor β1(TGF-β1), interleukin 17 (IL-17), and interleukin 10(IL-10) production were measured in the supernatants of all macrophage cultures. Indoleamine 2, 3 dioxygenase (IDO) and phagocytic activitywere analyzed in the different experimental groups. The supernatant effects of LPS-treated macrophages on splenocyte proliferation was assessed by the colorimetric method using a 3-(4,5-Dimethylthiazol- 2-yl)-2, 5-diphenyltetrazolium bromide (MTT) reagent., Results: According to cytokine analysis, different mouse strains show different cytokine patterns in response to LPS. C57BL/6 macrophages produced more IL-17, IL-10, and IFN-λ, while BALB/c macrophages produced more TGF-β1 and IL-4. There was no significant difference in IDO activity between strains (p≤0.05). BALB/c mice produced more NO inthe first 24 hours after LPS treatment,but C57BL/6 produced more NO at 72 hours post-LPS treatment. Macrophages from both strains hada suppressor effect on splenocyte proliferation, but this effect was stronger in BALB/c mice., Conclusion: The results show that macrophages from different genetic backgrounds respond differently to the same stimulus in aspects of type, intensity, and time of response. The consideration of these aspects will enableresearchers to use correct treatment programs for immune-regulation or immunotherapy.