Simultaneous Camouflage of Major and Minor Antigens on Red Blood Cell Surface With Activated mPEGs

-

Background: Host immune system response against blood group antigens is a major problem in blood transfusions, especially forthalassemic patients. Thus, an approach was proposed coating the red blood cell (RBC) surface by polyethylene glycol.Objectives: This study aimed to obtain the optimal simultaneous camouflge of the major and minor antigens by activated methoxypolyethylene glycol (mPEG) with succinimidyl valerate (SVA) and succinimidyl carbonate (SC), separately.Materials and Methods: The degree of RBC agglutination by antibodies against the major and minor blood groups was used as asurrogate measurement for quantitative assessment of the effctiveness of the surface coating. Also, the RBC morphology was assessedusing scanning electron microscope (SEM). In addition, to evaluate the host immune system response, the PEGylated RBCs were transferredbetween two diffrent mouse strains.Results: Statistical analysis of the results demonstrated that the optimal reaction conditions for simultaneous coating of the antigensby mPEG-SVA and mPEG-SC are as mPEG20 in the polymer mixture, 91.2 and 90.0%, and polymer concentration, 17.21 and 19.80 mg.mL-1,respectively. However, according to the SEM results, the maximum polymer concentration of 14.5 mg.mL-1 was suggested as the bestcondition for mPEG-SVA modifid human RBCs.Conclusions: It is concluded that the membrane PEGylation camouflges the blood group antigens. This effct is observed signifiantlyfor non-ABO/Rh(D) antigens. Also, it is found that the mPEG-SVA provide better coverage than mPEG-SC. The results of in vivo analysisshowed that the immune reactions against PEGylated RBCs were considerably reduced, so that the levels of the relevant biochemicalparameters in serum were similar to those of the normal hosts 24 hours after transfusion.