Evaluation of the immunoregulatory effect of Dicrocoelium dendriticum eggs on inflammatory and anti-inflammatory cytokines in EAE model.

Experimental autoimmune encephalomyelitis (EAE) is an appropriate model for the study of the immunologic and pathologic mechanisms in multiple sclerosis (MS). According to the hygiene hypothesis, helminths can improve immunoregulation and have therapeutic effects on immune-mediated diseases. In this study, we used Dicrocoelium dendriticum (Dicrocoeliidae, Platyhelminthes) eggs for the evaluation of their prophylactic and treatment effects on EAE disease. D. dendriticum eggs were extracted. Female C57BL/6 mice were immunized with the specific antigen MOG35-55 , and then the egg extracts were utilized for prophylaxis and/or treatment. Clinical symptoms and other relevant parameters were assessed daily. The mRNA expression of transforming growth factor-ß (TGF-ß), interleukin-10 (IL-10), IL-6, IL-23 and IL-17 were assessed with a real-time polymerase chain reaction technique. Furthermore, secretion of TGF-ß and IL-17 cytokines were determined by enzyme-linked immunosorbent assay. Data indicated that clinical symptoms in prophylaxis and treatment groups were decreased significantly in comparison with the untreated control group (p < .001). Our results showed a significant decrease in IL-17, as well as an increase in TGF-ß cytokine in the treatment group compared to the EAE control group (p < .01). Furthermore, in the prophylaxis and treatment groups, the mRNA expression of disease-associated cytokines decreased and the mRNA expression of the anti-inflammatory cytokines increased. In this study, the D. dendriticum egg ameliorates the clinical symptoms of the EAE model through the modulation of related cytokines of Th17 and Treg cells. Therefore, using this parasite egg could be a new treatment for MS.

Acylated and deacylated quillaja saponin-21 adjuvants have opposite roles when utilized for immunization of C57BL/6 mice model with MOG35-55 peptide.

BACKGROUND: The majority of patients with multiple sclerosis (MS) suffer from central neuropathic pain (CNP). Using experimental autoimmune encephalomyelitis (EAE) model, only a few experiments were performed to assess pain behaviors in MS. To address this issue, complete Freund's adjuvant (CFA) was replaced with an acylated triterpene glycoside saponin adjuvant named quillaja saponin-21 (QS-21) to develop CNP in the EAE mouse model. The deacylated form of QS-21, named QT-0101, has been suggested to have an immunomodulatory effect. Thus, QT-0101 was used as a vaccine adjuvant to modulate the immune system against myelin oligodendrocyte glycoprotein (MOG35-55) antigen. METHODS: In this study, C57BL/6 mice, except for mice in the negative control (PBS) and MOG groups, were divided into three groups and immunized by MOG35-55 emulsified with CFA, QS-21, or QT-0101 adjuvants, respectively. Thermal hyperalgesia, as a CNP clinical manifestation, through the Hot Plate test and the clinical signs, was assessed for 60 days after immunization. On days 21 and 60, mice were sacrificed and the frequency of TCD4+, TCD8+, IL-17+, IL-4+, and CD25+/FoxP3+ cells population in the total splenocytes population was assessed by flow cytometry. Infiltration of Leukocytes into the brain and demyelination of white matter were also evaluated by histopathologic studies. RESULTS: Our results revealed that unlike the MOG+QT-0101 group, the MOG+QS-21 and MOG+CFA groups represented clinical symptoms that mimic the mild relapsing-remitting and monophasic models, respectively. Thermal hyperalgesia, as a CNP clinical manifestation, developed in the bilateral hind paws in the MOG+CFA and MOG+QS-21 mice groups during the onset of neurologic deficits, but it is maintained until completion of the study only in MOG+QS-21 mice group. The frequency of TCD4+, TCD8+ and IL-17+ cells population in the MOG+QS-21 and MOG+CFA mice groups, as well as IL-4+ and CD25+/Foxp3+ cells population in the MOG+QT-0101 mice group, significantly increased in comparison with the PBS mice group. Infiltration of inflammatory cells increased significantly in the MOG+QS-21 and MOG+CFA mice groups compared with the PBS mice group. Demyelination of white matter was identified significantly only in the MOG+CFA mice group compared with the PBS mice group. CONCLUSION: These results showed that QS-21 is a suitable adjuvant for the establishment of a mild relapsing-remitting EAE model for CNP development and open a new avenue to future pre-clinical and clinical research studies related to CNP treatment. Nevertheless, QT-0101 seems to have the potential to act as a vaccine adjuvant with immunomodulatory property against auto-antigens.