The antimetastatic function of concomitant antitumor immunity. II. Evidence that the generation of Ly-1+2+ effector T cells temporarily causes the destruction of already disseminated XXXX cells.

@entity9600 @entity5 @entity19 @entity784 @entity262 @entity3
Progressive growth of the P815 @entity9600 in an immunocompetent host evokes the generation of an antitumor immune response that can be measured in terms of the production of cytolytic Ly-1+2+ T cells in the draining lymph node and spleen. This immunity, designated concomitant immunity, is present on day 6 of @entity5 growth, peaks on day 9, and decays progressively thereafter. It fails to develop in @entity19 made T cell deficient by thymectomy and lethal whole-body gamma-radiation, and reconstituted with syngeneic bone marrow cells (TXB @entity19 ). Employment of a @entity19 survival assay, capable of enumerating metastatic @entity19 cells in cell suspensions, showed that the P815 @entity5 metastasizes to the draining lymph node and spleen at the same rate in normal and TXB @entity19 for the first 6 days of growth of an intradermal P815 @entity5 . By day 6 of @entity5 growth there were approximately 10(3) @entity19 cells in the draining lymph node in both types of @entity19 . However, during the generation of concomitant immunity between days 6 and 9, the number of metastatic @entity19 cells in the draining lymph nodes and spleens of normal @entity5 -bearing @entity19 declined by nearly 90%. After day 12, however, the number of @entity5 cells in the nodes and spleens increased concordantly with the decay of concomitant immunity. These findings, together with the demonstration that @entity784 @entity19 failed to restrain the number of metastatic @entity19 cells in the draining lymph node and spleen, suggest that concomitant immunity is an important defense mechanism against the development of @entity262 . Additional evidence consistent with this interpretation was provided by studies which showed that adoptive immunization with spleen cells from concomitant immune donors significantly prolonged the median survival time of @entity5 -bearing @entity19 by destroying a substantial proportion of @entity19 @entity5 cells already seeded in the draining lymph node. Adoptive immunization also delayed the appearance of @entity3 cells in the spleen.
