Does L-Canavanine Ingestion Induce Murine SLE? Paradoxical Effects on Survival of BALB/c Mice

Observations in humans and macaques suggest that ingestion of an excess of alfalfa sprouts can induce systemic lupus erythematosus (SLE). Feeding L-canavanine increased the incidence of autoimmune symptoms in several strains of mice. The presence of L-canavanine in alfalfa sprouts could result in the synthesis of proteins rich in L-canavanyl residues and subsequent recognition of these modified endogenous proteins as foreign. The original purpose of this long-term study in BALB/c mice was to determine whether ingestion of L-canavanine did induce an SLE-like disorder by such a mechanism. Analysis of mortality patterns observed during that investigation of diet-induced autoimmune disease suggests that L-canavanine increases murine longevity. Eighteen female BALB/c mice were fed a diet containing 1.56% L-canavanine sulfate (equivalent to 1% L-canavanine base). Eighteen other mice received a control diet. The animals were monitored for the presence of anti-nucleic acids and survival. There was no evidence of anti-nucleic acid antibodies. However, 50% of control mice, compared with only 11% of canavanine-fed mice, died before 477 days of age (P < 0.05). Full life span studies of the effects of L-canavanine, with larger groups of mice from a variety of strains should be done to verify whether dietary L-canavanine is an alternative to nutrient restriction for increasing the life span of mice.