Figure 3.

Nessy mice produce lower titres of helper-dependent immunoglobulin G1 (IgG1) and IgG2a antibodies. Nessy (closed circles) and C57BL/6 (open circles) mice were immunized with 50 μg chicken gamma globulin (CGG) and approximately 10⁸ heat-killed Bordetella pertussis, and were bled from the tail vein 14 days postimmunization, or with 25 μg NP–Ficoll and bled from the tail vein 7 days postimmunization. Titres of IgG1 (a), IgG2a (b) or IgM (c) were determined by enzyme-linked immunosorbent assay. Data from three separate experiments are shown; averages are indicated by a horizontal bar. Data were analysed using Student's t-test; P values are indicated; data at or below the limit of detection (log titre of 2·0) are given a value of 2·0.