Background: Although the Luminex single antigen flow beads (SAFB) and the flow cytometry crossmatch (FCXM) are the most sensitive assays used for anti-HLA antibodies characterization in transplant... Show moreBackground: Although the Luminex single antigen flow beads (SAFB) and the flow cytometry crossmatch (FCXM) are the most sensitive assays used for anti-HLA antibodies characterization in transplant recipients, their semi quantitative fluorescence read-out is not closely linked to graft outcome.Methods: Surface plasmon resonance (SPR) was implemented to determine truly quantitative parameters of five human monoclonal anti-class I HLA antibodies (mAbs): first the active concentration and then the binding constants. The results were compared to those obtained with SAFB and T-cell FCXM (T-FCXM).Results: The five mAbs displayed different rate and equilibrium constants for their cognate antigens. No correlation was evidenced between SAFB MFI or T-FCXM ratio and the binding parameters measured by SPR. Some mAbs amino acid substitutions within the epitope that influenced SAFE MFI resulted in affinity variations evidenced by SPR.Conclusion: The SAFB MFI and T-FCXM ratio, both semi-quantitative parameters, only partially reflected the subtlety of the anti-HLA antibody/antigen interaction as it can be analyzed by SPR. Future clinical studies using SPR for anti-HLA antibodies characterization could bring novel insights into the understanding of HLA/anti-HLA interaction and therefore anti-HLA antibodies pathogenicity. Show less
This thesis is a collection of experimental attempts to enhance photoluminescence of fluorescent molecules and quantum dots with single gold nanorods (GNRs) and relevant applications. Special... Show moreThis thesis is a collection of experimental attempts to enhance photoluminescence of fluorescent molecules and quantum dots with single gold nanorods (GNRs) and relevant applications. Special attention is focused on the interactions between single emitters and GNRs. The idea is to increase the emission of weak emitters by the excellent optical properties of GNRs so that weak light emitters will then be bright enough to be detected and studied individually. We can thus generalize single-molecule fluorescence spectroscopy to weakly emitting species which are currently undetectable by conventional single-molecule spectroscopy. The research is important for extending the scope of single-molecule spectroscopy, which is a powerful technique for understanding the dynamic behaviors at the nanometer scale in biological systems and other materials. Show less
