Feasibility Of Baboon And Capuchin Monkeys As Animal Model Of Xenotransfusion Red Blood Cell

Purpose: Compare the merits and drawbacks of baboon and capuchin monkeys as xenotransfusion models,and provide experimental evidence for the selection of animal models for heterogeneous red blood cell infusion.Materials and Methods: Materials: Blood and sera of 42 baboons,10 capuchin monkeys,and 3 genotypes pigs were all provided by Revicor Corporation(Blacksburg,VA,USA).The blood types of the 3 genotypes pigs(GTKO,GTKO/β4GalNT2KO and TKO)were O blood group.Methods:(1)Detection of IgM and IgG antibody binding levels in serum of 3 genotypes pigs red blood cells and PBMC with 42 baboons using FCM;(2)Detection of CDC levels of 3 genotypes pigs PBMC in 42 baboons serum using FCM;(3)We used FCM to compare IgM and IgG antibody binding levels of baboons and Capuchin monkeys serum against TKO pig red blood cells(pRBCs);(4)FCM detection CD47 antigen expression on TKO pigs and capuchins red blood cells.Results:(1)FCM detection of antigen-antibody binding levels of 42 baboon sera against GTKO,GTKO / β4GalNT2KO and TKO pigs:(i)The binding levels of TKO pig red blood cells and baboon serum IgM antibody(rGM: 5.58)is slightly higher than that against GTKO / β4GalNT2KO(rGM: 4.65)pig.There is no significant difference in the binding of IgM to IgG(p> 0.05);(ii)The level of IgM antibody binding between PBMC of TKO pigs and baboon serum(rGM: 5.06)was much higher than that of GTKO / β4GalNT2KO(rGM: 2.33)and GTKO(rGM: 3.21).And the peak value of IgM antibody binding to TKO pigs(rGM: 9.38)was much higher than the other two(GTKO: 7.00;GTKO / β4GalNT2KO: 3.52),all of which were statistically significant(p <0.05),The average level of IgG antibodies(rGM: 1.57)that binds to PBMC of TKO pigs is also higher than that of GTKO(rGM: 1.31)and GTKO / β4GalNT2KO(rGM;1.29).There is statistical significance between TKO pigs and other 2 gene type pigs(p <0.05);(2)CDC results showed that TKO(85.11%)was much higher than GTKO / β4GalNT2KO(54.4%)and GTKO(54.4%).Even if TKO and GTKO had low(rGM <3)IgM and IgG antibody binding,their complement-dependent cytotoxicity is still higher than 40%,which is basically maintained above 80%.However,GTKO / β4GalNT2KO still had 14/42(33%)baboon cytotoxicity lower than 40% on the basis of low level IgM(rGM <3);(3)FCM detected the binding of TKO pig red blood cells to capuchin and baboon serum IgM and IgG antibodies.TKO pig red blood cells had positive IgM binding rates to baboon serum(rGM> 1.2).IgM antibody binding was negative in 3/10(30%)capuchin monkeys,and one were strongly positive,but the individual results of strong positives(rGM: 3.3)were still lower than the average of baboon serum binding(rGM: 4.81),and the remaining 6/10(60%)were all near the positive cutoff value(p <0.05),IgG antibody binding was not significant compared to IgM(p>0.05);(4)Capuchin erythrocytes can detect CD47 antigen positive,but pig red blood cells does not express CD47 antigen.Conclusion: 1.Baboons are not suitable as transplant recipients for TKO pigs.2.Capuchin is an ideal animal model for TKO pig xenotransfusion.3.The labeling of CD47 antigen can help distinguish red blood cells from primate animal and pigs.