7-P

Abstract

Aim Solid phase antibody detection assays using single antigens represent a cutting edge technology for screening the sera of transplant patients. Considering the large number of HLA targets, it has been difficult to QC all single allelic HLA entities with well characterized serological reagents. Our aim is to identify, generate, and characterize agreeable sera/antibodies for the quality control of single HLA antigens produced by various manufacturers. Methods Monospecific antibodies are considered the most appropriate means for the quality control of single antigens. A number of human and mouse monoclonal antibodies represent excellent reagents for quality assessment. However, monoclonal antibodies are not available for many HLA. Here, deconvolution of serological specimens, isolating mono-specific anti-HLA antibodies by an absorption-elution technology further assisted in increasing the reagent pool. We then utilize these monospecific antibodies for single HLA antigen QC purposes. Results We characterized HLA monospecific antibodies from dozens of candidate reagents. The purified antibodies were highly specific for specific HLA targets. Initial titration curves indicate an optimal performance range with a specific HLA. Thereafter, each monospecific reagent was screened for its HLA cross-reactive pattern. Crossreactivity coincides with known epitopes and suggests that clinically relevant and irrelevant epitopes are indicated. Conclusions Well-characterized sera/antibodies provide not only a consensus for antibody specificity, helping to standardize and QC existing HLA platforms, but also allow a consensus for the strength (MFI) of the antibody-HLA interaction. The provision of multiple HLA monospecific antibodies that can be harvested from patient sera by individual laboratories will enable multiple HLA single antigen QC. Furthermore, harvest of HLA monospecific sera will provide insights into HLA epitope structures, supporting the efforts to understand crossreactive HLA in the clinical lab.