Fig. 2

Spiking Study of Four Recombinant Flu Hemagglutinin and Covid Spike Antigens Using Various MS Parameters. (A) LC-PRM profile of four recombinant influenza hemagglutinin (HA) proteins (Wisconsin, Darwin, Austria, and Phuket) and recombinant SARS-CoV-2 S1 domain of spike protein at 2 pmol each spiked into negative control HEK293T cell pellets. (B) Quantitation results of spike study at high resolution (method 1). Antigen peptide signal (%) for each unique antigen relative to specific HEK293T peptide signal at each spike level were plotted and fit with linear curve. The fit slope and R² value for each antigen are provided in the table below. Orange: Covid; Black: Austria; Blue: Wisconsin; Magenta: Phuket; Red: Darwin. (C) Representative PRM profile of Wisconsin HA peptide EQLSSVSSFER at 0.13 and 2 pmol spike-in levels using high (method 1), medium (method 2), and low (method 3) resolution settings. (D) Quantitation results of spike study at medium resolution (method 2). Antigen peptide signal (%) for each unique antigen relative to specific HEK293T peptide signal at each spike level were plotted and fit with linear curve. The fit slope and R² value for each antigen are provided in the table below. Orange: Covid; Black: Austria; Blue: Wisconsin; Magenta: Phuket; Red: Darwin.