Influence of protein restriction on immune functions in NZB mice.

The influence of a low protein (6%) diet on the immunologic function of NZB mice was investigated. The low protein intake was associated with decreased weight gain in both male and female NZB mice. The mice fed the low protein diet did not develop splenomegaly, which generally occurs by 7 to 10 months of age in NZB mice fed a normal amount of protein. Further, 7- to 10-month-old NZB mice fed the low protein(6%) diet, maintained: 1) more vigorous antibody production to sheep red blood cells; 2) greater capacity to produce graft-vs-host reactions, and 3) more vigorous cell-mediated "killer" cell immunity after immunization against DBA/2 mastocytoma cells than did NZB mice on a normal (22%) protein diet. The decrease of PHA and Con A response which normally occurs with aging in NZB mice was abrogated to some degree by protein restriction. However, response to LPS, which also declines with age in NZB mice, did not appear to be influenced by diet.