Study On Modification Of Blood Group RhD Antigen On Human Red Cells With MPEG-SPA

OBJECTIVEThe aim of this study was to observe the effect of mPEG-SPA (methoxypolyethyl ene glycol-propionic acid N-succinimidyl ester )modification on Blood Group RhD antigen on human RBCs(Red Blood Cells),and discuss the feasibility of mPEG-SPA modification.METHODSThe mPEG-SPA was used to modify Blood Group RhD antigen on human RBCs, and subsequently its effect on morphology,structures,functions,ESR,deformability and routine index of human RBCs was observed.RESULTS(1) MPEG-SPA could camouflage RhD antigen efficiently when the concentration reached to 2.0mmol/L.(2) MPEG-SPA modified and unmodified human RBCs were observed by scanning electron microscopy which both showed normal morphology.(3) MPEG-SPA can bind human RBCs firm in 4℃for 2 weeks or in 37℃for 2 days.(4) 2.0mmol/L mPEG-SPA modification had no obvious influences On Osmotic fragility of human RBCs.(5) Spontaneous hemolysis of unmodified group and modified group were (1.32±0.32) % and (2.27±0.28)% respectively after 48 hr at 37℃.It showed that Modification of RBC does lead to a slight increase (P<0.05) in spontaneous hemolysis compared with unmodified RBCs.The results of both groups were in the normal range.(6) Cholesterol contents of human RBCs membrane in unmodified group and modified group were (0. 1±0.06) g/L and (0. 1±0. 03) g/L (P>0.05), respectively;AchE activity were(29.68±4.16)U/mg and (27.88±5.09) U/mg (P>0.05);Na+-K+ ATPase activity were (5.41±1.32)U/mg and (4.83±1.27)U/mg (P>0.05);2,3-DPG were (65.13±13.98)mmol/L and (71.00±12.88) mmol/L (P>0.05).There were no statistical difference between the two groups.(7) ESR(Estimation of erythrocyte sedimentation rate) of modified group was slower than unmodified group.They were (8.00±3.82)mm/H and (2.75±2.05)mm/H (P<0.05), respectively. The results of both groups were in the normal range.IDmax of RBCs in unmodified group and modified group were 0.98±0.29 and 0.98±0.18 (P>0.05) which were both above 0.51.(8) MCH and MCHC of modified group were higher than unmodified group(P<0.05). There were no statistical difference among MCV,RDW of modified group and unmodified group(P>0.05). The results of both groups were in the normal range.CONCLUSIONmPEG-SPA could camouflage RhD antigen efficiently and firm when the concentration reached to 2.0 mmol/L at room temperature at pH8.0.The result also showed that there were no obvious effects of mPEG modification on RBCs morphology,osmotic fragility,hemolysis,Cholesterol contents,AchE activity,Na+-K+ ATPase activity,2,3-DPGcontents,ESR,deformability and routine index. It is suggested that success in mPEG-SPA modification on Blood Group RhD antigen of human RBCs was preliminarily achieved.