Nonspecific Suppression of Tumor Growth by an Immune Reaction to Listeria monocytogenes2

Antitumor activity of Listeria monocytogenes on a guinea pig fibrosarcoma

“…Microorganisms which have been used for clinical and experimental immunotherapy of tumors included BCG (2,14,30), Corynebacterium parvum (11,21), Brucella abortus (26), Bordetellapertussis (15,24), Toxoplasma gondii (13), and Listeria monocytogenes (3,28,29). In addition to being potent reticuloendothelial system stimulants, many of these agents evoke an acquired cellular resistance in the host, which to a great measure nonspecifically inhibits tumor growth (10).…”

Immunoprophylaxis toward mammary carcinoma in mice immune to Listeria monocytogenes

“…The antitumor activity of LM infection on growth of transplantable mufine fibrosarcoma has been recently described by two groups [2,16]. Similary, the growth of B 16 melanoma is prevented or suppressed in the syngeneic host when Table 1) tumor cells are inoculated in contact with viable LM [15].…”

“…Similar conclusions on the basis of in vitro studies can be drawn from the experiments of Krahenbuhl and Remington [8], who showed that there is a latent phase of at least two days between the interaction of LM-activated macrophages with the tumor cell (Lline) monolayer and target cell destruction. Youdim et al [16] proved that immunologic commitment by the animals to LM antigens is required for tumor rejection. Mice incapable of developing immunity to LM were also incapable of preventing tumor growth following the transplantation of both fibrosarcoma and melanoma tumor cells.…”

“…This discrepancy is most likely due to the weak antigenicity of this type of tumor. Youdim et al [16], working with the same kind of tumor as Bast et al, demonstrated this by the inability of mice specifically immunized with fibrosarcoma cells to reject as few as 10 3 tumor cells, thus making any host-specific reactivity (or concomitant immunity) in this tumor-host system most improbable. An alternate explanation of the discrepancy between our data and those of Bast et al is that the adjuvant effect of LM on a specific anti-tumor response can develop only in LM-immune animals such as those used in our experiments, but not in normal hosts that have not been primed previously with LM.…”

Bacteriological and histopathological evaluation of guinea pigs after infection with Listeria monocytogenes

“…Use of Listeria infection in guinea pigs for the purpose of in vitro and in vivo characterization of acquired cellular resistance, delayedtype hypersensitivity, and lymphokine production has been under investigation in this laboratory (5,6). A very limited number of studies so far have employed Listeria in the potentiation of tumor immunity (1,2,12,13). Studies are currently being carried out in this laboratory on the ability of Listeria to effect modulation of tumor immunity using a guinea pigfibrosarcoma model.…”