Studies on Delayed (Cellular) Hypersensitivity in Mice Infected with Trichinella spiralis. IV. Artificial Sensitization of Donors

Abstract

In 3 experiments, it was demonstrated that 2 injections of supernatant material, collected after disruption and centrifugation of larvae, combined with Freund's complete adjuvant sensitized donor mice sufficiently so that after injection of their spleen cells recipients showed immunity as indicated by a significant reduction in adult worms compared with controls 12 days after infection. The adjuvant alone did not contribute to this effect, since recipients injected with cells collected from donors given 2 injections of adjuvant alone harbored about the same number of worms as the regular controls. The value of using spleen cells in such studies in mice, and of isolating a single provocative antigen for use in future studies, is discussed. In the last two papers of this series (Larsh et al., 1964, 1966), peritoneal exudate cells collected from infected donors conferred immunity upon recipients as proved by a significantly lower adult worm burden than in controls after a challenging infection. Although it has been shown in guinea pigs that a single small dose of a crude saline-extract antigen from T. spiralis larvae injected intradermally produced delayed hypersensitivity, as demonstrated by skin tests, that was transferred to recipients by spleen cells (Kim, 1966) or lymph node cells (Kim et al., 1967), this has not been reported from studies in mice. Therefore, the present study was designed to determine whether a crude extract antigen would sensitize our donors sufficiently to confer immunity upon recipients after the transfer of cells. In this case, the success of sensitization would be manifested by a significant reduction in adult worms after a challenging infection. In 10 unsuccessful experiments with peritoneal exudate cells, separate variables, such as methods of antigen preparation, size of sensitizing doses, and routes of injections and schedules for production of sensitivity, were manipulated in attempts to demonstrate immunity. At this point, it was decided to use spleen cells for transfer. In the report that follows, positive results were obtained in three experiments where spleen cells were taken from donors after two injections of an antigenadjuvant mixture. The antigen was the superReceived for publication 11 October 1968. natant extract obtained by disruption of T. spiralis larvae in a Ten Broeck Tissue Grinder followed by centrifugation at 1,000 g for 20