Data Normalization
For all multivariate analysis, positive antigens were removed (Tetanus
and H1Cal2009). If any antibody feature included negative values,
right-shifting was performed (by adding the minimum value for each
respective feature back to all samples). Data was then log transformed
to ensure that the majority of features were normally distributed, by
using the following equation log10 (x+1). Values were
subsequently normalized by mean centering and variance scaling by
calculating respective z -scores.