This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Robinson, M. K. Articles by Wheelock, E. F. Search for Related Content PubMed PubMed Citation Articles by Robinson, M. K. Articles by Wheelock, E. F.

Enhanced Suppressor Macrophage Activity Associated with Termination of the L5178Y Cell Tumor-dormant State in DBA/2 Mice¹

Department of Pathology and Laboratory Medicine, Hahnemann University, Philadelphia, Pennsylvania 19102

Both cytolytic T-lymphocytes and cytolytic macrophages have been implicated in the long-term maintenance of L5178Y cells in a tumor-dormant state in DBA/2 mice. Eventually, however, the tumor-dormant state terminates, and all mice develop ascitic tumors. In an evaluation of the mechanisms involved in termination of the tumor-dormant state, we detected in the peritoneal cavity of many tumor-dormant mice macrophages with increased capacity to suppress the in vitro generation of a secondary anti-L5178Y cell cytolytic T-lymphocyte response. The incidence of macrophage-mediated immunosuppressive activity in individual tumor-dormant mice was related directly to the number of tumor cells in the peritoneal cavity of those mice. Furthermore, in tumor-dormant mice harboring fewer than 5 x 10⁴ L5178Y cells, the detection of macrophage-mediated immunosuppressive activity was a prognostic indicator of termination of the tumor-dormant state and development of an ascitic tumor. These data suggest that peritoneal macrophage-mediated immunosuppressive activity, through inhibition of cytolytic T-lymphocyte generation in vivo, contributes to the termination of the tumor-dormant state and development of ascitic tumors.

¹ This research was supported by Grant CA32577 awarded by the National Cancer Institute, Department of Health and Human Services, and by Biomedical Research Support Grant 5 SO7 RR05413.

² Recipient of National Research Service Award 1 F32 CA 06940. Present address: Department of Immunochemistry Research, Evanston Hospital, Evanston, Ill. 60201.

³ Present address: Department of Immunopharmacology, Hoffmann-La Roche Inc., Nutley, N. J. 07110.

Received 4/15/83. Accepted 9/ 6/83.