Over-Expression of Immunosuppressive Molecules, PD-L1 and PD-L2, in Ulcerative Colitis Patients.

BACKGROUND: Ulcerative colitis (UC) and Crohn's disease (CD) are the two forms of inflammatory bowel disease (IBD). Adaptive immune responses involving helper T cells play an important role in developing IBDs. Programmed death (PD)-1 and its ligands namely PD-L1 and PD-L2 are negative costimulatory molecules that control T cell motility and formation of an immune synapse between T cells and antigen-presenting cells (APCs). OBJECTIVE: To investigate the role of PD-L1 and PD-L2 in patients with UC to clarify the mechanism of IBD development. METHODS: Biopsy specimens were obtained from 50 UC patients and 45 sex- and age-matched control subjects. Total RNA was extracted from all samples and applied for cDNA synthesis. Relative expression of PD-L1 and PD-L2 mRNA was determined using Taqman qRT-PCR. RESULTS: Relative gene expression levels of both PD-L1 and PD-L2 were higher in UC patients than the control groups (p<0.05 and p<0.01, respectively). Furthermore, both PD-L1 and PD-L2 expressions were positively correlated in all study subjects (r=0.339, p<0.001). However, among the groups with disease severity, the relative gene expression levels of PD-L1 and PD-L2 showed no significant difference. CONCLUSIONS: During IBD, the occurrence of PD-L1 and PD-L2 up-regulation may modulate the chronic inflammation of colonic mucosa.

Comparison of Eight Cell-Free Media for Maintenance of Toxoplasma gondii Tachyzoites.

BACKGROUND: Toxoplasmosis is considered as one of the most common infectious diseases caused by the protozoan parasite Toxoplasma gondii. Tachyzoite is the main form of Toxoplasma and continuously is maintained in cell culture or injected into the mice peritoneal cavity. This study was designed to evaluate the survival rate of RH strain of T. gondii tachyzoites in different cell free, nutrient and biological media at different temperatures. METHODS: This experimental study was performed at the Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran, in 2010. One ml of each solution including hypotonic saline (0.3%), normal saline (0.85%), RPMI-1640 (RPMI), RPMI with 10% fetal bovine serum (FBS), RPMI with 20% FBS, ovine hydatid cyst fluid, pasteurized milk of cow, and phosphate buffered saline (PBS) along with 4×10(4) T. gondii tachyzoites were added to plate wells and incubated in 4 °C, 22 °C, 37 °C, and 37 °C under 5% CO2. The survival rate and viability assessment of parasites were performed daily and the results were analyzed using Univariate tests. RESULT: Tachyzoites survival rate in PBS (4 °C) and normal saline (4 °C) were considerably high, compared to other solutions in different conditions (P<0.001). The best temperature for Toxoplasma maintenance was 4 °C (P<0.001). CONCLUSION: This study introduces two available and economical solutions, PBS (4 °C) and normal saline (4 °C) media, for maintenance of Toxoplasma tachyzoites as appropriate choice media for a noticeable period of time (11 days) in vitro.

Electrophoretic Patterns of Toxoplasma gondii Excreted/Secreted Antigens and Their Role in Induction of the Humoral Immune Response.

BACKGROUND: Toxoplasma gondii is an obligatory intracellular protozoan parasite on which studies are pending regarding production of vaccine. To date, the production of human vaccine has not been successful where approximately one third of the world's population is thought to be infected with T. gondii. OBJECTIVES: The present study was designed to compare the electrophoretic patterns of T. gondii excreted/secreted antigens (ESAs) and determine their role in the stimulation of the humoral immune response. MATERIALS AND METHODS: T. gondii ESAs were prepared from cell cultures (albino rat fibroblast) and cell-free mediums (RPMI-1640). Next, the SDS-PAGE technique was used for comparing molecular weights of the antigens. Forty C57BL/6 mice were divided randomly into four groups (n = 10). Immunization was performed subcutaneously at an interval of 2 weeks in two groups by injecting 100 µg of each of the above-mentioned antigens. Two groups, as negative control, also received fibroblast lysate proteins or adjuvant separately. All of the groups were then challenged with the T. gondii RH strain. Serum samples were collected from all mice and measured by immunoblotting technique for detection of immunogenic antigens. RESULTS: The electrophoretic mobility of the prepared antigens/proteins from cell culture, cell-free media, Fibroblast Lysate Proteins and Toxoplasma Lysate Antigens (TLA) showed 13, 12, 8 and 8 bands, respectively. The case groups, in challenge with T. gondii (RH strain), showed more survival prolongation than the control groups. Furthermore, the survival period was identical for both case groups with a tendency for slightly higher survival of mice receiving ESA from cell-free medium. Analysis of sera by immunoblotting also revealed one band of 65 KDa in sera from both case groups. CONCLUSIONS: We suggest that this band be extracted and its amino acids sequence determined to produce Synthetic Polypeptide for immunization studies.