Fig. 1: Assessment of potent neutralizing mAbs against PIV3 and epitope discovery on the head domain of the PIV3 HN protein.

A ELISA binding curves data displays mAb binding with high affinity to the head domain of HN. Data points are the average of four technical replicates from one experiment and are representative of two biological replicates. Data are presented as mean values +/− SD. B Plaque reduction neutralization test curves for the eight mAbs. Data points are the average of three technical replicates from one experiment and are representative of two biological replicates. Data are presented as mean values +/− SD. C Summary of the half maximal effective concentration (EC50) values and half maximal inhibitory concentration (IC₅₀) values calculated from (A) and (B). D PIV3-infected LLC-MK2 cells were stained with anti-PIV3 HN mAbs PIV3HN-05, and PIV3HN-09 conjugated to PE. Anti-F mAb PIA174 was used as a positive control, and a mAb against human metapneumovirus, MPV467, was used as a negative control. Both anti-HN mAbs and anti-F mAbs were detected in virally infected cells. Data represent the results from one technical replicate and are representative of two biological replicates. E Epitope binning was performed via biolayer interferometry (BLI) by loading His-tagged HN protein onto an anti-HIS sensor, and then associating the sensor with one mAb followed by a second mAb. Created in BioRender. Miller, R. (2024) https://BioRender.com/x68o050. F Three distinct epitopes on the PIV3 HN protein were discovered from the competitive binding to HN by the mAbs. Data indicate the binding of the second antibody to the sensor in the presence of the first antibody. Values in black boxes describe mAbs with high levels of competition (≤ 30), whereas values in white boxes describe mAbs that do not compete for binding (≥ 70).