FIGURE 4.

Multiple distinct MHC class II-restricted β₂GPI T cell epitopes are associated with B cell epitope spread to SLE autoantibodies. Sera from β₂GPI/LPS-immunized mice were tested for IgG antibodies to human β₂GPI (1:5000 dilution) and CL (1:1000 dilution) (A) and dsDNA, Ro (SS-A), La (SS-B), Sm, and nRNP (1:50 dilution) (B) by ELISA. The data shown for C57BL/6, C.B10, BALB/c, and B6.C mice are post-third immunization (black circles), whereas the data for all C3H/HeN mice and two 129S1 mice are post-second immunization (white circles) (see “Mice and Immunization”). Sera from mice of the same strain, immunized with PBS and LPS, served as a negative control in these assays. The mean value for PBS/LPS-immunized mice (n = 2 for each strain) is shown as a dotted line for each autoantibody assay. In certain cases, the mean value for the controls is very close to zero and so may be difficult to distinguish from the x axis. Each circle represents the mean IgG antibody binding (A₄₀₅ ± S.E.) of duplicate samples for an individual mouse (n = three to six mice/group), and the data shown are representative of three independent experiments.