AN ENHANCED IMMUNE-RESPONSE IN MICE LACKING THE TRANSCRIPTION FACTOR NFAT1

Transcription factors of the NFAT family are thought to play a major r ole in regulating the expression of cytokine genes and other inducible genes during the immune response. The role of NFAT1 was investigated by targeted disruption of the NFAT1 gene. Unexpectedly, cells from NFA T1(-/-) mice showed increased primary responses to Leishmania major an d mounted increased secondary responses to ovalbumin in vitro. In an i n vivo model of allergic inflammation, the accumulation of eosinophils and levels of serum immunoglobulin E were increased in NFAT1(-/-) mic e. These results suggest that NFAT1 exerts a negative regulatory influ ence on the immune response.