Toxoplasma gondii activates NLRP12 inflammasome pathway in the BALB/c murine model.

The host resistance against Toxoplasma gondii (T. gondii) infection is related to the initiation of the immune response. The study aimed to investigate the role of the leucine-rich repeat family, pyrin domain -containing protein 12 (NLRP12), and cytoplasmic nucleotide-binding domain in the inflammasome-mediated cell death during murine toxoplasmosis. Groups of BALB/c mice (n = 10) were inoculated intraperitoneally with live tachyzoites, excretory-secretory antigens (ESAs) of T. gondii RH strain, and RPMI. The gene expression levels of NLRP12, caspase-3, caspase-1, IL-1ß, IL-18, ASC, and Bcl-2 were measured in the peritoneal cells using quantitative real-time PCR, while the determination of NLRP12 protein level was measured by Western blot. Also, the intracellular reactive oxygen species (ROS) production was investigated. Quantitative and comparative analyses showed that injection of tachyzoites significantly increased NLRP12, caspase-3, caspase-1, IL-1ß, IL-18, and ASC genes mRNA expression levels (p<0.01). Contrary to the acute infection, the Bcl-2 gene was significantly expressed in the ESAs group (p<0.0001). The level of NLRP12 protein was significantly higher in the mice that received tachyzoites and ESAs in comparison to the control group (p<0.0001). These findings provide an inside into the host-T. gondii interaction and NLRP12 regulation, which is important for the modulation of the immunological response.

Targeting Strategies in Therapeutic Applications of Toxoplasmosis: Recent Advances in Liposomal Vaccine Delivery Systems.

Toxoplasma gondii is a prevalent parasitic pathogen that infected over one-third of the global population. Toxoplasmosis is diagnosed by isolating the parasite and detecting host antibodies. In contrast, the main problem with diagnosis relates to the sensitivity and specificity of the tests. Currently, treatment with pyrimethamine and sulfadiazine is recommended, despite their side effects and toxicity to humans. Moreover, the absence of a vaccine to completely protect against this infection is the main obstacle to the effective treatment and prevention of toxoplasmosis. Recently, nanoparticles and nanomaterials have been studied as delivery systems for the immunization and treatment of T. gondii infections. One of the most important applications of liposomes is drug and vaccine delivery, due to their biodegradability, low inherent toxicity, and immunogenicity. Liposomes are flexible delivery systems and immunological adjuvants able not only to load diverse antigens, such as proteins, peptides, nucleic acids, and carbohydrates but also to combine them with immunostimulators. Liposomes have the incredible potential within the development of modern types of vaccines and numerous endeavors have been made to improve the effectiveness of vaccines in recent years. In this review, we concentrate on the viable targeting strategies of liposome-based vaccine delivery systems to prevent, control and treat toxoplasmosis.

Sero-molecular evaluation of Toxoplasma gondii infection among HIV-positive patients.

BACKGROUND: Toxoplasmosis is one of the most common comorbidities in HIV-positive patients with CD4+ T lymphocytes below 200 cells/µl. Early diagnosis and treatment of toxoplasmosis reduces the mortality rate in HIV-positive people. The aim of this study was to estimate the seroprevalence of Toxoplasma gondii infection in HIV-positive patients in northwest Iran using serological and molecular methods. METHODS: This prospective cross-sectional study included 124 HIV-positive outpatients and was conducted from January to May 2016. Anti-T. gondii IgM and IgG antibodies were detected from sera samples by chemiluminescence, while buffy coat samples were analyzed by RT-PCR for DNA detection. Patients' socioepidemiological data were collected. RESULTS: Using chemiluminescence, 47/124 samples (37.9%) were positive for anti-Toxoplasma IgG antibodies, 2/124 samples (1.62%) were positive for IgM antibodies while 2/124 samples (1.62%) contained both IgM and IgG. There were no IgM-positive or IgG-negative patients. RT-PCR revealed four (3.22%) positive samples. On the basis of the results, a statistically significant relationship was found between anti-Toxoplasma IgG antibody seropositivity and residence (p=0.012). CONCLUSIONS: The study showed a relatively low seroprevalence of anti-T. gondii IgG and IgM antibodies in HIV-positive patients in northwest Iran, while the prevalence was much higher in other regions of Iran. However, regular screening for T. gondii antibodies and early initiation of therapy are very important to decrease the mortality rate in HIV-positive patients.

IL-17 and IL-22 elicited by a DNA vaccine encoding ROP13 associated with protection against Toxoplasma gondii in BALB/c mice.

Toxoplasma gondii, an intracellular parasitic protozoan, is capable of infecting man and all warm-blooded animals. Cell-mediated immunity is vital in mounting protective responses against T. gondii infection. Recent studies have shown that T-helper (Th) 17 responses may play a key role in parasite control. In this current study, we constructed a DNA vaccine encoding T. gondii ROP13 in a pcDNA vector. Groups of BALB/c mice were immunized intramuscularly with pcROP13 or controls and challenged with the RH strain of T. gondii. The results showed that immunization with pcROP13 could elicit an antibody response against T. gondii. The expression of the canonical Th17 cytokines, interleukin (IL)-17 and IL-22, were significantly increased after immunization with pcROP13 compared with control groups ( p < 0.05). Furthermore, vaccination resulted in a significant decrease in parasite load ( p < 0.05). The induction of Th17 related cytokines, using a ROP13 DNA vaccine, against T. gondii should be considered as a potential vaccine approach for the control of toxoplasmosis.

Quantification of Toxoplasma gondii in the tissues of BALB/c mice after immunization with nanoliposomal excretory-secretory antigens using Real-Time PCR.

BACKGROUND: Toxoplasmosis is an infectious disease caused by the intracellular parasite Toxoplasma gondii. Although almost 1/3 of the world's population are seropositive, there is no effective vaccine against toxoplasmosis. Therefore, the development of an effective vaccine for control of toxoplasmosis is one of major concerns in parasitology. The aim of this study was to evaluate the efficacy of nano-liposomal excretory-secretory antigens (NLESA) in BALB/c mice. MATERIALS AND METHODS: Excretory-secretory antigens (ESA) was obtained from tachyzoites, encapsulated in the liposome and studied by scanning electron microscope. BALB/c mice were immunized with NLESA and ESA, sterile phosphate-buffered saline (PBS). Immunization was performed three times at 14-day intervals and challenged with 1 × 104 tachyzoites of T. gondii RH strain four weeks later. The parasite load of mice blood, brain and spleen tissues were determined using quantitative PCR targeted at the repeated element (RE) gene. RESULTS: The immunization with NLESA and ESA induced a significant increase of anti-Toxoplasma IgG antibody compared with PBS group (P < 0.05). After challenge with tachyzoites, qPCR analyses showed significant reduction of parasite load in NLESA and ESA immunized mice compared with control group (P < 0.05). Also, NLESAs were more effective than ESAs and showed significantly reduced parasite load in blood (P = 0.001) and brain tissue (P = 0.01). DISCUSSION: The vaccination with NLESA showed more promising results comparing to ESA. Further studies are recommended in order to achieve effectiveness of the vaccine against T. gondii.

Bioemulsifiers Derived from Microorganisms: Applications in the Drug and Food Industry.

Emulsifiers are a large category of compounds considered as surface active agents or surfactants. An emulsifier acts by reducing the speed of chemical reactions, and enhancing its stability. Bioemulsifiers are known as surface active biomolecule materials, due to their unique features over chemical surfactants, such as non-toxicity, biodegradability, foaming, biocompatibility, efficiency at low concentrations, high selectivity in different pH, temperatures and salinities. Emulsifiers are found in various natural resources and are synthesized by Bacteria, Fungi and Yeast. Bioemulsifier's molecular weight is higher than that of biosurfactants. Emulsion's function is closely related to their chemical structure. Therefore, the aim of this paper was to study the various bioemulsifiers derived from microorganisms used in the drug and food industry. In this manuscript, we studied organisms with biosurfactant producing abilities. These inexpensive substrates could be used in environmental remediation and in the petroleum industry.