Figure 1. IgM responses to whole Pneumocystis antigen in Pneumocystis-naive mice.

(A) Anti-Pneumocystis IgM titers in WT C57BL/6 mice. (B) Anti-Pneumocystis IgM titers in Aicda^–/– and Rag2^–/– mice. In this assay, an OD of more than 0.1 was considered positive. The asterisk denotes significant differences between Aicda^–/– and Rag2^–/– mice (by Mann-Whitney).