IL4 and infection: To test whether IL-4 was sufficient to regulate pro-inflammatory gene transcription in RAG−/− mice, we administered IL-4 complex (IL-4c) to infected RAG−/− mice during pre-patent infection and examined pro-inflammatory gene transcription in the spleen at week six p.i. Administration of IL-4c resulted in down-regulation of IL-1β and TNF transcription in the spleens of treated RAG−/− mice (Figure 7A and 7B), similar to that observed in wild type mice and RAG−/− mice treated with LPS, MSU or anti-TNF.