Rheumatic fever (RF) is an autoimmune complication that can arise in some patients following inadequately treated strep throat infections. It may progress to rheumatic heart disease, a major cause of preventable cardiovascular morbidity and mortality in children, impacting over 40 million people worldwide. Identifying children at risk for developing RF, estimated at 3-5% of the population, presents significant global health and economic opportunities.
A promising approach for identifying RF susceptibility involves the mouse IgM antibody D8/17. This antibody binds more effectively to B-cells from RF patients than to those from controls across various ethnicities and regions. However, mixed results have hindered its development as a diagnostic tool, and the specific antigen targeted by D8/17 remains unidentified. To improve testing efficacy, we employed recombinant engineering to create new IgM and IgG1 variants of D8/17. These derivatives were more reliable in our flow cytometry and in vitro assays, suggesting they may be better diagnostic reagents.
We utilized these recombinant antibodies in multi-omics analyses to investigate the differences between immortalized B-cell lines derived from RF patients and control subjects. Western blot and MS/MS proteomic techniques identified cytoskeletal proteins in RF B-cells that exhibited increased reactivity with our recombinant variants. RNA sequencing supported these findings and revealed variations in gene expression of B-cell surface proteins, kinases, and signaling pathways among different D8/17 FACS populations of RF patient B-cells compared to controls. Overall, our analyses aim to identify markers or genetic factors associated with RF development and contribute to advancing diagnostic tools for RF susceptibility.