B-cell ELISPOT Assay for HLA-Specific Antibody Detection
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Solution Overview
Problem
Current methods for detecting antibody-secreting B cells specific for HLA in transplant settings are unreliable and cannot accurately quantify memory B cells capable of producing donor-directed anti-HLA antibodies, leading to underestimation of humoral immune responses and increased risk of humoral rejection in transplant patients.
Innovation Solution
A novel B-cell ELISPOT assay that stimulates memory B cells, captures secreted antibodies, and uses HLA multimers to detect antibody-secreting cells, allowing for the quantification of HLA-specific antibody-producing memory B cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional serological assays (CDC, ELISA, flow cytometry, Luminex) are used to detect donor-specific antibodies, then the detection of circulating HLA antibodies is achieved, but the memory B-cell pool is excluded leading to underestimation of the humoral immune response
Solution Approach 1:
The invention merges two separate detection capabilities into a single assay system: (1) detection of secreted antibodies and (2) detection of memory B cells. By combining ELISPOT technology with HLA multimer staining, the assay simultaneously identifies memory B cells that both express HLA-specific BCRs and secrete anti-HLA antibodies, thereby capturing the full humoral immune response including the previously undetected memory B-cell pool
Solution Approach 2:
The invention introduces HLA multimers as an intermediary tool that bridges the detection gap. These multimers serve as specific probes that bind to HLA-specific antibodies secreted by memory B cells, enabling the indirect detection of memory B cell activity through their antibody secretion products. This intermediary approach allows visualization and quantification of functional memory B cells without requiring direct antigen stimulation
2Reliability
If highly sensitive assays are used to detect circulating anti-donor HLA antibodies, then circulating antibodies are detected, but patients with robust memory B-cell responses but undetectable circulating antibodies are missed
Solution Approach 1:
The assay performs preliminary activation of memory B cells before detection, allowing these cells to differentiate into antibody-secreting cells and release their antibodies. By pre-stimulating the memory B cells in culture conditions that promote differentiation and antibody secretion, the assay converts a population of cells with latent antibody-producing capacity into a detectable signal, thereby revealing sensitization status that would otherwise remain hidden in circulating blood
3Quantity of substance
If current immune-monitoring tools are used, then circulating alloantibodies are measured, but the full magnitude of the effector alloimmune response is underestimated
Solution Approach 1:
The assay employs colorimetric detection through HLA multimers that produce visible color changes at the site of antibody secretion. Each spot representing an antibody-secreting memory B cell exhibits a distinct color signal, allowing direct visualization and quantification of the total antibody-producing cell population. This color-based detection method enables precise counting and measurement of the full magnitude of the alloimmune response, far exceeding the quantification capability of conventional serum antibody assays
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The assay effectively identifies patients at high risk of humoral rejection by detecting HLA-specific antibody-secreting B cells, even in the absence of circulating antibodies, thereby improving pre-transplant assessment and post-transplant monitoring.
Implementation Method 1
contacting the captured antibodies with at least an HLA multimer of said HLA and detecting the HLA multimer of said HLA bound to the captured antibodies
Data Source
AI summary
The invention relates methods for detecting antibody-secreting B-cells specific for at least an HLA in a subject. The invention also relates to kits for developing said methods and to the use of said methods for determining the risk of a subject having humoral rejection against an allogeneic transplant, for determining the risk of a subject of suffering endarteritis associated with post-transplant humoral rejection after allogeneic organ or tissue transplant, for selecting a subject to receive a transplant, and for determining the presence of humoral sensitization against HLA.