The efficacy of BCG-induced tumor immunity in guinea pigs with regional and systemic malignancy

Histological evaluation of immunologically mediated tumor regression of the line 10 guinea pig hepatocarcinoma

The histology of immunologically mediated tumor regression was studied in the syngenic strain 2 guinea pig/line 10 hepatocellular carcinoma tumor system. Tumor regression was induced non-specifically by the intralesional injection of living Bacillus Calmette-Guérin (BCG) in 7-day-old established tumors (diameter 8-10 mm). In untreated line 10 tumors at day 7 a mild to moderate inflammatory reaction was present, which consisted mainly of small mononuclear cells; in addition large mononuclear cells and basophils were present. Intratumoral BCG-treatment induced a prominent increase in the inflammatory reaction due to an influx of small and large mononuclear cells and neutrophils. Small mononuclear cells were identified mainly as lymphocytes whereas large mononuclear cells belonged mainly to the macrophage line. Intratumoral administration of BCG resulted in a granulomatous reaction. A time-related decrease in the number of tumor cells and an increase in inflammation, associated with purulent lysis of the granulomatous tissue, was observed. Specific immune-mediated tumor rejection occurred in animals both after active immunization and after adoptive transfer of immune spleen cells. In actively immunized animals the tumor cells were rapidly rejected and from day 4 onwards no tumor cells could be detected at the injection site. Lymphocytes were the major component of the inflammatory reaction; large mononuclear cells were present to a lesser extent and basophilic granulocytes were regularly observed. After adoptive transfer of immunity with immune spleen cells given simultaneously with an intradermal innoculation of tumor cells, an essentially similar rejection reaction was found, although tumor cell rejection was delayed. Lymphocytes and large mononuclear cells were found in equal proportions, whereas basophilic granulocytes were always present in smaller numbers. After BCG-induced regression and in adoptively transferred immune rejection, a fibroblast component was more prominent than in untreated control tumors. This reaction tended to isolate smaller tumor cell areas into islets of decreasing sizes. In contrast with the fibroblast component of growing tumors, the proliferative pre-existing fibrous tissue in tumors undergoing regression or rejection showed a loosely arranged architecture and contained a marked cellular infiltrate. From the results of the present study it was concluded that the morphological expression of line 10 tumor rejection varies. Without immune cells, BCG is needed for the induction of a local inflammatory reaction, which was granulomatous in type and eventually led to complete tumor cell eradication.(ABSTRACT TRUNCATED AT 400 WORDS)

Enhancement of metastasis development by BCG immunotherapy

When BALB/c mice bearing growing transplants of a syngeneic colon carcinoma--Colon Tumor 26 (CT 26)--were treated with Bacillus Calmette-Guerin (BCG), no effect on tumor growth rate or survival time was observed compared to untreated controls. However, after excision of primary tumor transplants, enhanced development of lung metastases was noted in the BCG-treated mice, resulting in both as increased mortality rate (from metastatic disease) and a shorter survival time.

BCG immunotherapy of lung cancer

Thirty-three patients have undergone BCG intralesional injection into pulmonary tumors. Six received the injection by way of the bronchoscope and 27 were injected percutaneously under fluoroscopic control. The toxicity of this treatment is closely related to PPD reactivity. PPD-negative patients have little fever and malaise. However patients with strongly positive PPD reactions have extensive and prolonged fever. Twenty-six of the 27 patients injected with BCG underwent pulmonary resection. There were no significant postoperative complications. Histologically BCG induces a granulomatous inflammatory reaction, and in the patients who are PPD-positive there is extensive plasma-cell infiltration and de novo germinal center formation within the tumor. Eighty-five percent of the patients with bronchogenic carcinoma and 58 percent of the patients with metastatic cancer are alive and well at a median follow-up of 16 months following pulmonary resection.

Tumoricidal effects of Mycobacterium ulcerans toxin on murine adenocarcinoma (C3HBA)

Fresh homogenized mammary gland adenocarcinoma (C3HBA) material was subcutaneously inoculated in the anterior right thigh of transplant host mice (C3H/HeJ). When tumors were palpable, the mice were separated into three groups. The test group received biweekly intratumoral injections of Mycobacterium ulcerans filtrate containing 40 mg of protein per ml. One control group received intratumoral injections of normal physiological saline, and the remaining group received no treatment at all. The survival rate of toxin-treated animals was 13.5% at 15 weeks when compared with the control groups. Additionally, tumor metastasis was apparently abrogated in test animals when compared to the control animals. Marked necrosis of the tumors in the test animals was noted by histological examination. Controls showed slight to moderate degrees of tumor necrosis. In this model Mycobacterium ulcerans toxin appears to have therapeutic value as an antitumor agent.

Specific immunotherapy of established visceral micrometastases by BCG-tumor cell vaccine alone or as an adjunct to surgery

A vaccine of Bacillus Calmette-Guérin (BCG) admixed with tumor cells induced systemic immunity and had a therapeutic effect on subclinical, disseminated micrometastases. Inbred strain 2 guinea pigs given intravenous injections of either 10(4), 10(5) or 10(6) syngeneic L10 hepatocarcinoma cells were vaccinated after metastatic foci were established in the lung parenchyma. The studies demonstrate that under defined conditions of vaccine preparation and regimen, nontumorigenic preparations of BCG and tumor cells can cure the majority of animals of otherwise lethal visceral metastases. Histopathologically it was determined that immunization with these vaccines prevented the progressive growth of pulmonary micrometastatic foci approximately 0.1 mm in diameter. However, in this micrometastasis therapy model, the number of metastatic tumor foci is a major limitation in the efficacy of vaccine therapy. No protection against L10 tumor was achieved when antigenically distinct but syngeneic L1 hepatocarcinoma was used in the vaccine, suggesting that this is a tumor-specific immunotherapeutic procedure. This BCG-L10 tumor vaccine was also effective in curing guinea pigs of minimal disseminated tumor burden when administered after surgery of an established skin tumor and draining lymph node.

Clinical and immunologic studies of disseminated BCG infection

Eight patients with disseminated BCG infection following injection of BCG into primary melanomas have been studied. These patients developed persistent fevers beginning 9 to 20 days following BCG injection. Severe liver function abnormalities occurred in all patients and peaked approximately 20 days following BCG injection. The persistent fevers, and clinical signs and symptoms of disseminated BCG infection lasted from 7 to 22 days before subsiding. Liver function abnormalities sometimes took six months to return to normal. Evidence of granulomas in liver and bone marrow were present. The natural course of this disease did not appear to be affected by therapy with isoniazid (INH). In vitro immunologic studies revealed a severe depression of lymphocyte reactivity in five of six patients sequentially tested. Wide dissemination of BCG from the site of injection is a severe complication of BCG therapy. The clinical course of this disease and suggestions for management are described in this paper.