Definition of antibody development:
In ELNA and IFA, a change in antibody titer of more than one dilution
step over the investigation period from time point 1 (T1) to time point
5 (T5) was defined as an increase or decrease of the titer. In the IgG
CLIA assay, the development of antibodies was defined as a change in
chemoluminescence of more than 50%.