DNA barcode-antibody conjugates (DNA-Abs) are used to identify multiple specific biomarkers on single cells. However, it is uncertain whether such conjugates lose sensitivity and specificity during DNA labeling. DNA labels reside in lysine residues on antibodies for non-site-specific labeling, and if the labels reside in the antigen-binding site, it can interfere with antibody binding. Therefore, my project investigates both site-specific (Oyo-Link Alpha Thera) and non-site-specific labeled antibodies (AbSeq and TotalSeq-A) to identify whether non-site-specific labeling interferes with DNA-Ab bindings.

By indirect immunofluorescence, which we stained CD8 cells with DNA-labeled primary antibodies CD45RA, CD8, CD28, and CD38 and with different concentrations of secondary antibody (anti-mouse PE sAb) and polydT (AF647), we compared the fluorescent signal results of these DNA-Abs. Our results indicate no significant signal difference between TotalSeq and Oyo-Link conditions, which suggests non-site-specific labeling did not interfere with DNA-Ab bindings. The results of diluting sAb and polydT indicate fluorescent signal expressions are antibody-dependent. Also, the signal difference when staining with different sAb concentrations for CD45RA Oyo-Link indicates potential interference between sAb and polydT bindings.