PLGA nanoparticle-delivered Leishmania antigen and TLR agonists as a therapeutic vaccine against cutaneous leishmaniasis in BALB/c mice.

Leishmaniasis, caused by Leishmania (L.) species, remains a neglected infection. Therapeutic vaccination presents a promising strategy for its treatment. In this study, we aimed to develop a therapeutic vaccine candidate using Leishmaniaantigens (SLA) and Toll-like receptor (TLR) 7/8 agonist (R848) encapsulated into the poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs). Moreover, TLR1/2 agonist (Pam3CSK4) was loaded onto the NPs. The therapeutic effects of these NPs were evaluated in L. major-infected BALB/c mice. Footpad swelling, parasite load, cellular and humoral immune responses, and nitric oxide (NO) production were analyzed. The results demonstrated that the PLGA NPs (SLA-R848-Pam3CSK4) therapeutic vaccine effectively stimulated Th1 cell responses, induced humoral responses, promoted NO production, and restricted parasite burden and lesion size.Our findings suggest that vaccination with SLA combined with TLR1/2 and TLR7/8 agonists in PLGA NPs as a therapeutic vaccine confers strong protection againstL. majorinfection. These results represent a novel particulate therapeutic vaccine against Old World cutaneous leishmaniasis.

Differential Expression of miR-146 and miR-155 in Active and Latent Tuberculosis Infection.

Background: Tuberculosis (TB) is one of the leading causes of death worldwide. Besides, one-third of the world population is infected with Mycobacterium tuberculosis (MTB) while staying clinically asymptomatic; the situation is called latent TB infection (LTBI). MiR-21, miR-31, miR-146a, and miR-155 play an important role in many immune and inflammatory pathways. In the present study the expression levels of MiR-21, miR-31, miR-146a, and miR-155 in peripheral blood mononuclear cells (PBMCs) from patients with active TB, latently infected individuals (LTBI), and healthy controls (HC) were investigated. Participants were recruited at the Bouali Hospital, Zahedan University of Medical Sciences, Zahedan, Iran from 2010 to 2011. Methods: PBMCs were stimulated with PPD before RNA extraction. TaqMan RT-qPCR assay was used to analyze the expression levels of miRNAs. Results: The results indicated no significant differences in the expression of miR-21 and miR-31 between different groups; however, in patients with active TB, the expression of miR-21 (P=0.03) and miR-31 (P=0.04) were significantly increased after stimulation with PPD compared to the unstimulated condition. The expression of miR-146 in response to PPD in both LTBI (P=0.02) and TB (P=0.03) groups compared to the HC group was increased. No significant differences were found in the expression level of miR-155 in response to PPD between LTBI and HC groups. However, the fold change was significantly higher in the TB group in comparison with the HC (P=0.03) and LTBI (P=0.05) groups. Conclusion: The results confirm the main role of miR-146 and miR-155 in TB infection and suggest a role for miR-146 and miR-155 as infection and activation markers in tuberculosis infection, respectively.

The role of microbiota and immune system crosstalk in cancer development and therapy.

Cancer is a multifactorial disease that is the second leading cause of death after cardiovascular disease in the world. In recent years, microbiota's role in the regulation and homeostasis of the immune system has been considered. Moreover, the immune system can affect the microbiota content. These interactions are critical to the functioning of the immune system. Numerous studies in animal and human models have shown the association of changes in microbiota components with the formation of an inhibitory microenvironment in the tumor and its escape from the immune system. Microbiota also plays a crucial role in the success of various anti-tumor treatments, and its modification leads to success in cancer treatment. The success of anti-tumor therapies that directly target the immune system, such as immune checkpoint blockade and T cell therapy, is also affected by the patient's microbiota composition. It seems that in addition to examining the patient's genetics, precision medicine should pay attention to the patient's microbiota in choosing the appropriate treatment method, and together with usual anti-tumor therapies, microbiota may be modified. This review discusses various aspects of the relationship between microbiota and anti-tumor immunity and its successful treatment.

Impact of gut microbiota on immune system.

The commensal microflora collection known as microbiota has an essential role in maintaining the host's physiological homeostasis. The microbiota has a vital role in induction and regulation of local and systemic immune responses. On the other hand, the immune system involves maintaining microbiota compositions. Optimal microbiota-immune system cross-talk is essential for protective responses to pathogens and immune tolerance to self and harmless environmental antigens. Any change in this symbiotic relationship may cause susceptibility to diseases. The association of various cancers and auto-immune diseases with microbiota has been proven. Here we review the interaction of immune responses to gut microbiota, focusing on innate and adaptive immune system and disease susceptibility.

Combinatorial delivery of antigen and TLR agonists via PLGA nanoparticles modulates Leishmania major-infected-macrophages activation.

Appropriate activation of macrophages is critical for the elimination of Leishmania parasites, which resides in this cell. Some species of Leishmania (L.) fails to stimulate macrophages and establish a chronic infection. To overcome this suppression and induce an innate immune response, the effect of PLGA-encapsulated soluble antigens of Leishmania (SLA) along with agonists of TLR1/2 (Pam3CSK4) and TLR7/8 (R848) nanoparticles (NPs) on activation of L. major-infected-macrophages were investigated and were compared with those of soluble formulations. SLA and R848 were encapsulated into the PLGA, while Pam3CSK4 adsorbed onto the surface of nanoparticles. The kinetics of pro-inflammatory cytokines (IL-1ß, IL-6, and TNF-α) and iNOS genes expression were investigated by qPCR over 72 h. The parasite load was also quantified by qPCR. The results indicated that engulfment of L. major promastigotes does not induce any pro-inflammatory cytokines expression by macrophages; however, the infected-cells are capable of responding to the TLRs agonists, and a lesser extent, to the SLA stimulation. Encapsulation resulted in increased strength of the IL-1ß, IL-6, TNF-α, and increased and prolonged time of iNOS expression. Also, encapsulation showed the leishmanicidal activity by decreasing parasite load in treated NPs formulations. Among the different combinations of the components, the triple (SLA-R848-Pam3CSK4) forms promoted the highest activation of macrophages, followed by dual SLA-Pam3CSK4 and SLA-R848 NPs. In conclusion, the findings of this study indicate that the addition of SLA in combination with TLR1/2 and TLR7/8 agonists either in NPs or in soluble forms overcome the suppression of L. major-infected macrophages. Moreover, encapsulation increases the strength and duration of the cytokines and iNOS expression, in parallel with decreasing parasite load, suggesting a longer availability or delivery of the NPs into the macrophages. These findings highlight the advantages of particulate therapeutic vaccine formulations.