Intravenous Injection of Myelin Oligodendrocyte Glycoprotein-coated PLGA Microparticles Have Tolerogenic Effects in Experimental Autoimmune Encephalomyelitis

The abnormal function of the T lymphocytes causes a range of autoimmune diseases, particularly multiple sclerosis; hence, several methods have been used to treat these disorders through the induction of antigen-specific tolerance in T cells. The present study aims to use a simple and low-cost method to produce poly (lactic-co-glycolic acid) (PLGA) nanoparticles for carrying antigens and inducing antigen-specific tolerance. In this study, PLGA nanoparticles were produced using the water/oil/water (W/O/W) method. The myelin oligodendrocyte glycoprotein (MOG) peptide and ovalbumin peptide(OVA) were covalently bound to the synthetic PLGA nanoparticles in the presence of 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDCI) and were injected to six groups of C57BL/6 mice one week before the induction of the experimental autoimmune encephalomyelitis (EAE) intravenously or subcutaneously; one group was considered as control; finally, immunologic responses including delayed-type hypersensitivity (DTH) response and lymphocyte proliferation were investigated. The results showed that the intravenous injection of microparticles containing MOG peptides before the development of the EAE model, not only could delay the incidence of syndrome, but also increase the antigen-specific tolerance. Moreover, a reduced delayed-type hypersensitivity response was observed in the mice primed with microparticles containing MOG peptides. In addition, a reduced spleen lymphocyte proliferation was found in the same mice when challenged with antigens. The present study proposes a simple, inexpensive, effective and safe method for preparing MOG-conjugated PLGA microparticles with immune tolerance properties that can be used in the treatment or reducing clinical syndromes of EAE model.