Therapeutic effect of cell-wall skeleton of Propionibacterium acnes in combination with a monoclonal antibody (C6-1.2) on the lung metastases of Lewis lung carcinoma.

The purpose of this study was to determine whether the combination of C6-1.2 monoclonal antibody (MoAb) (established in our laboratory), which is specifically reactive with Lewis lung carcinoma (3LL), and cell-wall skeleton of Propionibacterium acnes C7 (P. acnes-CWS) would significantly decrease established spontaneous metastases of 3LL. C6-1.2 MoAb combined with intratumoral (or intralesional) injection of P. acnes-CWS, when administered at an early stage of the experiment, showed a significant reduction of lung metastases in 3LL-bearing mice. The treatment modality of C6-1.2 MoAb alone did not decrease the lung tumor colonies. On the other hand, the combined treatment of intravenous injection of P. acnes-CWS and C6-1.2 MoAb did not significantly reduce the lung metastases of 3LL tumors in 3LL-bearing mice compared with the treatment of P. acnes-CWS alone. In contrast, when the primary tumor was surgically removed, the most remarkable reduction of lung metastases was observed by the combination of intravenous administration of both C6-1.2 MoAb and P. acnes-CWS. We concluded that the antimetastatic activity of C6-1.2 MoAb and P. acnes-CWS varies depending on the injection route, and also that surgical excision of the primary tumor can lead to remarkable reduction of 3LL lung metastases.

Stimulation of cytokine production in mice using deacetylated chitin.

The effect of 70% deacetylated chitin (DAC-70) on the production of cytokines in mice was examined. DAC-70 stimulated the production of colony-stimulating factor and interferon at 6 to 12 h and 24 h after intraperitoneal injection, respectively. Interleukin 1 and colony-stimulating activity were induced in the supernatants of thioglycolate-induced macrophages stimulated with DAC-70 in vitro. However, DAC-70 did not stimulate the production by spleen cells of interleukin 2, interferon, colony-stimulating or macrophage-activating factor or of interferon by macrophages in vitro. DAC-70 showed no effect on the production of tumour necrosis factor in vivo.

Adjuvant and antitumour activities of synthetic lipid A analogues.

The biological activities of synthetic glycolipids, which were chemically synthesized and based on the structure of lipid A of the lipopolysaccharide (LPS) from Escherichia coli, were examined with special reference to their adjuvant activity on the induction of delayed-type hypersensitivity, activity on the induction of tumour necrotic factor (TNF) and tumour regressive activity on line 10 hepatoma in strain 2 guinea pigs. Among them, a compound structurally corresponding to free E. coli lipid A (compound 506) as well as LPS exhibited potent adjuvant activity in the induction of delayed-type hypersensitivity in guinea pigs and TNF inducing activity in the sera of mice which were presensitized with Propionibacterium acnes. Compound 506 showed potent lethal toxicity in the intravenous administration of BALB/c mice presensitized with P. acnes. The regressive activity on line 10 hepatoma was observed by the multiple intralesional injection of squalane-treated compounds 504 and 505 in strain 2 guinea pigs.

Antitumor activity on line 10 hepatoma in strain 2 guinea pigs and pharmaceutical properties of quinonyl-MDP preparations.

The pharmaceutical properties of quinonyl-MDP-66 were discussed with special reference to the stability of oil-in-water emulsion, distribution capacity into regional lymph nodes and tumor regressive activity. The oil-in-water emulsion of quinonyl-MDP-66, which was prepared by treatment of quinonyl-MDP-66 with squalane (25 x) and emulsified with aqueous solution of 5% HCO-60 and 5.6% d-mannitol, was kept in lyophylized state and used after reconstitution by the addition of water before use. The reconstituted suspension of quinonyl-MDP-66 in oil-in-water emulsion was stable for more than 24 hrs. The oil-in-water emulsion of quinonyl-MDP-66 as prepared above was effective for the distribution of quinonyl-MDP-66 into regional lymph node in rats and for the regression of line 10 hepatoma in strain 2 guinea pigs by intralesional injection.

Macrophage activation with pantethine and pantetheine-4'-phosphate.

Adjuvant activities of pantethine (PaSS) and pantetheine-4'-phosphate (PSH-4'-P) were investigated in mice. By the multiple intraperitoneal administration, both PaSS and PSH-4'-P activated the functions of mouse peritoneal adherent cells and splenic natural killer cells. PSH-4'-P was also effective for the activation of natural killer cells by single injection. In in vitro, PaSS induced interleukin-1 (IL-1) secretion at a low concentration but PSH-4'-P did not. Both PaSS and PSH-4'-P could neither induce interleukin-2 (IL-2) secretion, nor could enhance IL-2 secretion by Con A.

Monoclonal antibodies to Lewis lung carcinoma.

Hybridoma cultures producing monoclonal antibodies were derived from fusions of the parent myeloma P3-X63-Ag8-U1 with spleen cells of BALB/c mice which had been immunized with the Lewis lung carcinoma (3LL) of C57BL/6 mice. Four monoclonal antibodies (A8-2.7, C6-1.2, D12-2.7), and G8-1.6) showed high reactivity to 3LL cells but showed no or low reactivity to other tumor cells, cultured cell lines, and normal tissues from C57BL/6 mouse. The C6-1.2 antibody was confirmed to have a binding capacity specific to 3LL cells by absorption assay and inhibition assay. Antigenic analysis indicated that the C6-1.2 antibody bound to 3LL surface glycoprotein (approximately 45,000 daltons), and other antibodies reacted with proteins (less than 10,000 daltons) on the cell surface of 3LL. Administration of C6-1.2 antibody i.v. reduced the metastasis into the lungs of 3LL in C57BL/6 mice.