IgG production in LAM-CRT-immunized nude mice. Groups of BALB/c nu/nu mice (6 per group) were immunized with laminarin (A), LAM-EGFP (B), or LAM-CRT (C) and then bled at different time points. The antisera (mixture of equal proportions; 1/200 dilution) of each group were assayed, in triplicate wells, for IgM and IgG using laminarin-based ELISAs. Sera from day 28 were titrated against laminarin for IgG1 (D). The results are expressed as mean OD492 ± SD. *, P < 0.05; **, P < 0.01; ***, P < 0.001; n.s., not significant. Results are representative of 3 independent experiments.