Transfer of murine host protection by using interleukin-2-dependent T-lymphocyte lines

We have demonstrated in this study that long-term, interleukin-2 (IL-2)-dependent, salmonella antigen-specific T-lymphocyte lines, as well as peritoneal exudate-enriched T cells, could be developed from both the antigen-sensitized inguinal and periaortic lymph nodes. Only those lines (salmonella-specific lymph node cells or peritoneal exudate T cells) were capable of adoptively transferring significant host protection (P less than 0.01) compared with the immune reactions of lethally challenged naive controls or of mice that had ovalbumin-specific T-cell lines transferred. Of particular interest was the finding that IL-2-dependent T-cell lines derived from the lymph nodes could only confer host protection to naive mice when both the transfer and challenge dose were administered via the intravenous route. Likewise, those T-cell lines derived from the peritoneal exudate were only capable of adoptively transferring significant protection when the cells and challenge dose of salmonellae were administered intraperitoneally. These studies indicate that systemic host protection can be transferred to naive mice, but depending on the source, the IL-2-dependent T-cell lines (lymph node or peritoneally isolated) functioned differentially upon challenge. Also, the results of this study indicate that the administration of greater numbers of IL-2-specific T cells may result in decreased, rather than enhanced, host protection. This may be due to the fact that the IL-2-dependent T-cell population consisted of 20 to 25% Lyt-2,3+ cells, indicating that cells of the suppressor/cytotoxic phenotype were present. Thus, increasing the number of cells transferred may result in an abrogation of protection.