Trypanosoma lewisi infection in the rat: effect of adenine.

The reproductive activity of Trypanosoma lewisi was strikingly enhanced and sometimes prolonged for 2 days when sublethal doses of adenine were given to rats. The drug was effective when given for 5 or 7 days in the diet and/or intraperitoneally, starting one or two days before infection through two days after infection. Peak parasitemia was also enhanced. In terms of host immunity, daily sublethal doses of adenine given to rats within two days before or after infection with T. lewisi significantly depressed a hitherto unrevealed natural immunity to reproduction of the trypanosomes, but only slightly modified the development of acquired immunity.