Abnormal responses to ingested substances in murine systemic lupus erythematosus: apparent effect of a casein-free diet on the development of systemic lupus erythematosus in NZB/W mice.

To assess the development of oral tolerance to casein in NZB/W female mice, they must be bred and raised on a casein free diet. We examined the specific immune responses of the mice to the long term experimental feeding of casein. Twelve of fifteen casein free mice were still alive at 10 months of age, although by this age only 1/10 mice eating the normal diet was still alive. The casein free mice had markedly less anti-DNA antibody, their IgM to IgG antinative DNA switch was delayed and deposits of immunoreactants in the glomeruli were greatly decreased. The reason for this apparent effect of the removal of casein from the diet is unknown; however, immunostimulatory and endorphin-like regions have recently been reported in casein.