Assessment of immune responses in serum
LTB
Vaccine-specific LTB and O78 LPS IgA and IgG antibody levels were determined in serum samples collected shortly before onset of immunization (Day 1) and 5–6 days after second dose. The responses were analyzed by an electrochemiluminescence assay, which is based on the Meso Scale Discovery (MSD) technology using plates precoated with LTB or O78 LPS, respectively, as described in detail earlier.