Effects of Calcium Cyclamate on the Immune Response in Rabbits

Date of Graduation

Spring 1974


Master of Science in Biology



Committee Chair

Richard Myers


Cyclamate was removed from the market as a nonnutritive sweetner in 1969 because rats fed cyclamate developed bladder tumors. Since that time, experimentation has centered around the effects of cyclamate and a major metabolite, cyclohexylamine, on several experimental animal systems. To determine the effect of cyclamate on immune factors in rabbits, one group of rabbits was given a 3 percent water solution of cyclamate, another a 5 percent solution and a third group served as a control and received no cyclamate. After 150 days of receiving cyclamate, the three groups were checked for neoplasia of the urinary bladder, spleen, thymus and lymph node. Each group was checked for the number of white and red blood cells and for cyclamate conversion and excretion in the urine. Finally, the ability to respond immunologically to bovine serum albumin was determined. No neoplasia was noted in histological sections of the tissues examined. The 5 percent group had fewer red blood cells and showed an inability to increase the number of white blood cells after antigenic exposure. Cyclohexylamine concentration in the urine increased and a retarded immune response was also noted. Up to the present the main deliterious effects of cyclamate has been thought to be due to its involvement in tumor production. In the present study cyclamate was shown to retard the immune response even though no tumors were observed. Current cancer research suggests that many tumors might arise as a result of a failure in the immune response. This study further supports this relationship and shows that the immune response is indeed affected even before tumors can be detected. This study suggests that more intense consideration should be given to the effects of carcinogens on the immune response rather than the effects that possibly initiate carcinogenicity.

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© Cecil Monroe Hampton