PDF(Pubmed)
Abstract：
Xenotransplantation is a potential option for individuals for whom an acceptable human allograft is unavailable. Individuals with broadly reactive HLA antibodies due to prior exposure to foreign HLA are potential candidates for a clinical xenotransplant trial. It remains controversial if allosensitisation results in the development of cross-reactive antibodies against SLA. This may require increased histocompatibility scrutiny for highly sensitised individuals prior to enrollment in a clinical trial. Serum samples were obtained from non-human primates sensitised via serial skin transplantation from maximally MHC-mismatched donor, as reported. Sera from pre- and post-allosensitisation timepoints were assessed in a flow crossmatch (FXM) for IgM and IgG binding to pig splenocytes with or without red blood cell adsorption. Xenoreactive antibodies were eluted from pig splenocytes and screened on a single antigen HLA bead assay. A MHC Matchmaker algorithm was developed to predict potential conserved amino acid motifs among the pig, NHP, and human. Our sensitised NHP model was used to demonstrate that allosensitisation does not result in an appreciable difference in xenoreactive antibody binding in a cell-based FXM. However, antibody elution and screening on single antigen HLA beads suggest the existence of potential cross-reactive antibodies against SLA. The cross-reactive IgG after allosensitisation were predicted by comparing the recipient Mamu alleles against its previous allograft donor Mamu alleles and the donor pig SLA alleles. Our study suggests that allosensitisation could elevate cross-reactive antibodies, but a more sensitive assay than a cell-based FXM is required to detect them. The MHC Matchmaker algorithm was developed as a potential tool to help determine amino acid motif conservation and reactivity pattern.
摘要：
异种移植是无法获得可接受的人类同种异体移植的个体的潜在选择。由于先前暴露于外源HLA而具有广泛反应性HLA抗体的个体是临床异种移植试验的潜在候选者。如果同种异体致敏导致针对SLA的交叉反应性抗体的发展，则仍存在争议。这可能需要在参加临床试验之前对高度敏感的个体进行更多的组织相容性审查。血清样品是从非人类灵长类动物中获得的，这些灵长类动物通过来自最大MHC不匹配供体的连续皮肤移植致敏，据报道。在具有或不具有红细胞吸附的情况下，在流式交叉匹配（FXM）中评估了来自变态反应前后时间点的血清中IgM和IgG与猪脾细胞的结合。从猪脾细胞中洗脱异反应性抗体并在单抗原HLA珠测定中进行筛选。开发了MHCMatchmaker算法来预测猪之间潜在的保守氨基酸基序，NHP,和人类。我们的致敏NHP模型用于证明同种异体致敏不会导致基于细胞的FXM中异种反应性抗体结合的明显差异。然而,抗体洗脱和在单抗原HLA珠子上的筛选提示存在针对SLA的潜在交叉反应性抗体.通过比较受体Mamu等位基因与其先前的同种异体移植供体Mamu等位基因和供体猪SLA等位基因来预测同种异体致敏后的交叉反应性IgG。我们的研究表明，同种异体致敏可以提高交叉反应性抗体，但是需要比基于细胞的FXM更灵敏的检测方法来检测它们。MHCMatchmaker算法被开发为帮助确定氨基酸基序保守性和反应性模式的潜在工具。
