Studies on the heterologous immunogenicity of a methanol-insoluble fraction of attenuated tubercle bacilli (BCG). II. Protection against tumor isografts

Role of the Immune System in the Growth of an Isotransplanted Urethan-Induced Lymphosarcoma

Two groups of (SWR×C57BL)F1 mice were injected subcutaneously with two quantitatively different cell suspensions from a uretan-induced thymic lymphoma of the same hybrid combination. Each of these groups was divided before the neoplastic isograft into the following sub-groups: controls, cyclophosphamide injected, X-irradiated and BCG injected mice. Percentage of takes, tumor diameters and mortality provided the parameters for the evaluation of the tumor growth. With the higher inoculum of neoplastic cells (5×105) only cyclophosphamide was effective in enhancing the take percentage 10 days after the isograft. With the smaller inoculum (5 × 103) all treatments were effective on tumor growth although the inhibitory action of BCG was not as strong as the enhancing action of the immune depressive treatments. The results are interpreted as evidence of a specific antigenicity of urethan-induced lymphoma.

Applications of bacillus Calmette-Guerin and recombinant bacillus Calmette-Guerin in vaccine development and tumor immunotherapy

Bacillus Calmette-Guerin (BCG) vaccines are attenuated live strains of Mycobacterium bovis and are among the most widely used vaccines in the world. BCG is proven to be effective in preventing severe infant meningitis and miliary tuberculosis. Intravesical instillation of BCG is also a standard treatment for non-muscle invasive bladder cancer. In the past few decades, recombinant BCG (rBCG) technology had been extensively applied to develop vaccine candidates for a variety of infectious diseases, including bacterial, viral, and parasite infections, and to improve the efficacy of BCG in bladder cancer therapy. This review is intended to show the vast applications of BCG and recombinant BCG (rBCG) in the prevention of infectious diseases and cancer immunotherapy, with a special emphasis on recent approaches and trends on both pre-clinical and clinical levels.

BCG and the treatment of superficial bladder cancer

In this report, we review the evolution of bacillus Calmette-Guérin (BCG) immunotherapy as a legitimate form of treatment in superficial, nonmuscle-invasive bladder cancer. In the US, an estimated 45,000 new cases of bladder cancer are diagnosed each year and the annual death rate approaches 11,000. Approximately 70 percent of these cancers are superficial at the time of initial presentation. The treatment of superficial bladder cancer has three objectives: (1) eradication of existing disease, (2) prophylaxis against tumor recurrence, and (3) prevention of tumor progression (either muscular invasion, metastatic spread, or both). Cystectomy generally is reserved for muscle-invasive disease. Transurethral resection of the bladder tumor is the preferred initial therapy. Intravesical instillations of various chemotherapeutic agents following transurethral resection have been extensively investigated. Some of the common agents used include thiotepa, mitomycin, and doxorubicin. Despite such treatment efforts, however, over 40 percent of patients with superficial bladder cancer experience a recurrence of their tumor within three years. Approximately half of these recurrences either present as less-well-differentiated tumors or have already penetrated into the bladder musculature, metastasized, or both. Since Morales et al. first introduced intravesical BCG vaccine for prophylaxis as well as for treatment of superficial bladder tumors in 1976, support has grown rapidly for its use as an alternative to chemotherapy. When used with prophylactic intent following transurethral resection, recurrence rates are lower than those achieved with other agents. In addition, BCG is emerging as the consensus drug of choice for treating carcinoma in situ of the bladder. The mechanisms by which BCG exerts its antitumor activity remain largely unknown. BCG is thought to stimulate a localized, nonspecific inflammatory response that leads to subsequent shedding of tumor cells. A large body of clinical and experimental data suggest an association between the development of an immunologic response to BCG and successful antitumor activity. No universally accepted therapeutic regimen has been agreed upon. One regimen commonly used consists of an ampul of BCG mixed with 50 mL of NaCl 0.9%, instilled once a week for six weeks and retained for two hours prior to voiding. Maintenance therapy generally consists of intravesical doses given at three-month cycles for at least two years of recurrence-free follow-up. Because BCG is a biologic agent, the commercially available products may differ in weight, colony-forming units per vial, and antigenicity. How these product characteristics affect clinical responsiveness to different strains of BCG remains unanswered.

A 64 kDa protein from Mycobacterium bovis BCG shares the same antigenic determinants with line 10 hepatoma cells and has anti-line 10 tumor activity

A 64 kilodalton (kDa) surface protein was isolated from the water-extracted materials from Mycobacterium bovis strain BCG, the determinants of which are antigenically shared by a 64 kDa major surface antigenic component of line 10 hepatoma cells. The 64 kDa protein showed anti-line 10 tumor activity in pre-immunized guinea pigs, and this suggest that the BCG 64 kDa protein is probably identical with the tumor specific antigen.

Squamous cell carcinoma of bladder after successful intravesical therapy with Bacillus Calmette-Guérin

A case of invasive squamous cell carcinoma of the bladder following intravesical immunotherapy with Bacillus Calmette-Guérin in a patient with pre-existing squamous dysplasia of the bladder is presented.

Does bacillus Calmette-Guérin immunotherapy accelerate growth and cause metastatic spread of second primary malignancy?

In our study, 29 of 150 patients with bladder cancer also had other associated primary malignancies, 10 of which were manifested after intravesical treatment with bacillus Calmette-Guérin (BCG). Second primary malignancies developed in 5 of these patients within three months of the start of BCG therapy. All 5 showed acceleration of the second primary tumor, and distant metastatic lesions developed in 4. In the other 5 patients nonbladder primary malignancies developed eight months or more after intravesical BCG therapy started, but did not show acceleration or spread. Twenty patients with other primary malignancies that had developed months to years before intravesical therapy did not show acceleration or spread of those tumors. We have seen enough cases of patients who received intravesical BCG at the time of growth and spread of second primary malignancies to warrant concern. Animal and human studies of BCG use for treatment of malignancy indicate that the temporal relationship between the starting point of tumor development and the starting point of BCG treatment is crucial in determining whether BCG will eradicate or exacerbate the tumor. We have therefore instituted a change in our treatment until the question of whether or not BCG causes the appearance and spread of these second malignancies is answered.

An assessment of neck node immunoreactivity in head and neck cancer

Current conventional forms of cancer treatment represent non-specific modalities that destroy not only cancerous but also non-cancerous tissue in an effort to totally eradicate the neoplasm. It was unknown in head and neck cancer whether a more specific form of treatment, as it relates to neck nodal disease, was advisable. The purpose of this investigation was to study the cervical node immunoreactivity in head and neck cancer patients as a means of determining their immunologic capabilities and thus provide information about the merits of specific vs. non-specific cancer treatment. The results demonstrated that lymphocytes arising from cervical nodes caused alterations in the tumor growth. There appeared to be no particular difference in immunoreactivity of lymphocytes arising from nodes located in different areas of the neck. The regional immune system of neck nodes in the head and neck cancer patient appears to be capable of mounting an immune response irrespective of the patient's tumor status. Usual measures of systemic immunocompetence failed to identify any patients with advanced stage disease and showed little correlation with the regional immunoreactivity. The regional nodal immunoreactivity also did not correlate with the size or the numbers of metastatic neck nodes. The results demonstrate that cervical neck nodes are capable of mounting an immune response to head and neck cancer and are not mere passive filters that are periodically involved with tumor emboli. These results support the need for the development of reliable treatments which are directed at tumor tissue only.

Haemorrhagic tumour necrosis following endotoxin administration. I. Communication: morphological investigation on endotoxin-induced necrosis of the methylcholanthrene (Meth A) tumour in the mouse

Endotoxin induced necrosis of the Meth A mouse tumour has been investigated using macroscopic, histological and ultrastructural examination methods. On the 8th day after tumour cell transplantation, the animals received a relatively non-toxic dose of the Salmonella abortus equi endotoxin intravenously. The natural history of the tumour necrosis took the following course: The earliest morphological changes could be seen with the electron microscope 90 min after administration of the endotoxin, and were seen as an interstitial oedema with separation of the tumour cells. Haemorrhagic necrosis of the tumour was complete 4 hours after injection, and could be easily recognized with the naked eye. Rejection of the necrotic malignant tumour was complete two weeks after LPS administration. Only minor residual scarring of the belly-wall remained. Haemorrhagic tumour necrosis due to endotoxin can be compared with the localized Shwartzman reaction and probably involves tumour necrotizing factor (TNF). For complete destruction of a tumour by haemorrhagic necrosis the size of the tumour is critical. Certain regression after endotoxin administration depends upon additional T-cell-mediated immunity (provided the tumour is immunogenic). In contrast to the haemorrhagic necrosis, BCG-induced tumour regression is accompanied by granulomatous inflammation, which may be responsible for destruction of the tumour.

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.

Evaluation of vindesine and MER in colorectal cancer

Vindesine, a derivative of vinblastine, was administered to 39 patients with advanced colorectal cancer refractory to 5-fluorouracil alone or in combination with other chemotherapeutic agents. The initial dose of vindesine was 4 mg/m2 administered intravenously (IV) over 30 minutes every two weeks. Tumor regression of more than 50% was seen in 2 and stable disease in 13 of 33 patients evaluable for response. Prior treatment with vincristine did not seem to influence response to vindesine. The median survival time was four months. The major toxic effect of vindesine was peripheral neuropathy, which occurred in 35% of patients who received two or more courses of treatment. Methanol extract residue of BCG (MER) was administered IV to 20 of 39 patients receiving vindesine without randomization in order to evaluate toxicities associated with IV MER. The most common toxic reactions to MER were fever and chills, while malaise and headaches were less common. Transient respiratory distress associated with appearance of reticulonodular pulmonary infiltrates occurred in 1 patient. Thus, MER at a dose of less than 1 mg/m2 did not seem to significantly influence the response rate to vindesine or the survival of patients. However, it appeared to ameliorate the myelosuppression caused by vindesine.

Systemic complications of MER immunotherapy of cancer: pulmonary granulomatosis and rash

BCG immunotherapy often has severe complications in cancer patients despite lack of toxicity in the immunocompetent individual. MER, a cell wall fraction of BCG, has been reported to cause immunopotentiation similar to that of BCG without equivalent toxicity. Recently, animal models have been reported to develop MER complications, especially disseminated granuloma formation, like those of BCG. For the past several years, MER has been used as adjuvant immunotherapy for treatment of malignant tumors with minimal systemic toxicity reported. A patient with malignant melanoma was treated with intralesional MER at the site of local metastases. He developed military pulmonary granulomatosis and a severe cutaneous eruption in association with MER therapy. The toxicities of BCG and MER therapy were compared with the pathogenesis of granuloma formation reviewed. This patient's complications were consistent with a hypersensitivity reaction to MER. Pulmonary granulomatosis and rash must be added to the list of known MER toxicities.

MER-BCG (NSC-143769): immunogenicity and toxicity of single and repeated intradermal injections in dogs

Intradermal injections of MER-BCG 0.1 mg or 0.2 mg at each of 10 multiple sites, led to local granuloma formation. The nodules reached approximately 10 mm in diameter, ulcerated and were accompanied by granulomatous changes in the regional lymph nodes. Six or twelve successive treatments (each including 10 injections) at 4 week intervals produced the same histopathological lesions but no changes in hematological and blood chemical parameters or general morphology and no changes in general condition with exception of occasional weight loss in a few animals. Injection with 0.01 or 0.001 mg/site produced similar, though less severe, skin lesions but no changes in the draining lymph nodes. The immunogenicity of MER-BCG was characterized by granuloma formation, a positive skin response to old tuberculin, and a positive lymphocyte transformation to PPD tuberculin, thus indicating stimulation of cell-mediated immune responses. However, there was a decreased responsiveness to PHA and PPD with continuing treatment with MER-BCG. The decreased responsiveness and accumulation of numerous depots of antigen would suggest an "immunologic paralysis" contraindicating the administration of excessive amounts of MER-BCG during immunotherapy. A specific humoral response to the administration of MER-BCG was not detected, but an MER-BCG dose independent decrease in albumin associated with a non-specific, dose related elevation in serum IgG was observed.

Surgical adjuvant immunotherapy for colorectal cancer

One hundred forty-four Wistar-Furth rats in 12 therapeutic groups have been studied in a long-term comparison of the effectiveness of nonspecific immunotherapy with MER (methanol extraction residue) vs active-specific immunotherapy with neuraminidase-modified tumor cells. Six months after surgical adjuvant immunotherapy a 100% improvement in survival was achieved with MER immunotherapy compared to untreated control animals. In addition, the use of MER enhanced the value of active-specific immunotherapy where both modalities were combined in sequence. The predicted value of MER-BCG (Bacillus Calmette-Guerin) for the immunotherapy of solid tumors was borne out by these results suggesting that present ongoing clinical trials of MER as adjuvant therapy for large bowel cancer should prove to be successful if properly controlled. The pattern of survival in these experiments suggests that surgical adjuvant immunotherapy is cytostatic rather than cytocidal, and implies the need for long-term, repeated immunizations.

Efficacy of intralesional BCG therapy in guinea pigs with disseminated tumor

It has been previously demonstrated that transplanted syngeneic tumors established in the skin of inbred (strain-2) guinea pigs regressed and regional lymph node metastases were eliminated after intralesional injection of viable Mycobacterium bovis (BCG). During the course of this reaction there is the development of tumor-specific immunity. This experimental model was further manipulated in order that it would more closely approximate a clinical reality. In the present study an evaluation was made of the effectiveness of the developing tumor-specific immunity in this BCG therapy model, to abrogate artifically induced distant tumor deposits and to assess the requirement for tumor-specific immunity in the local BCG-mediated tumor regression. During BCG-mediated regression of established intradermal tumor, the developing tumor-specific immunity inhibited the growth of artificially induced vascular metastases in animals receiving a 10(4) or 10(5) tumor cell dose. However, there is a direct causal relationship between the distant tumor burden and the escape of skin tumor and regional lymph node metastases from BCG-mediated regression. Thus, multiple tumor deposits as low as 10(4) cells are capable of competing for or preempting tumor-specific immune reactivity, which must be a requirement during some phase of the intralesional BCG-mediated therapy of established tumor and regional lymph node metastases. Thus, a significant therapeutic effect could be achieved in guinea pigs with established skin tumors and limited vascular metastases when the modality of therapy included BCG intralesional injection, followed 6 weeks later by surgery of the treated skin tumor and regional lymph node.

Enhancement of immunity against murine syngeneic tumors by a fraction extracted from non-pathogenic mycobacteria

The data reported here demonstrate that a preparation extracted from nonpathogenic mycobacteria such as Mycobacterium smegmatis and hereafter referred to as interphase material protected mice against Ehrlich ascitic carcinoma, L-1210 leukemia, and another syngeneic lymphoid leukemia. Furthermore, mice treated by this preparation were much less susceptible to endotoxins than when stimulated by BCG (bacillus Calmette-Guerin) or M. smegmatis cells. Moreover, guinea pigs treated by interphase material administered in Freund's incomplete adjuvant showed an increased immune response, yet their sensitivity to tuberculin was much weaker than that of controls sensitized with Freund's complete adjuvant. Finally, resistance to Columbia SK virus infection could be demonstrated when interphase material was administered to mice prior to virus challenge.

Histological and combined chemoimmunostimulation therapy studies against a murine leukemia

A Graffi murine leukemia was utilized as a model system to investigate the effect of chemoimmunostimulation therapy. Subcutaneous inoculation of approximately 1.0 times 10(6) tumor cells resulted in a rapidly growing tumor at the site of inoculation and subsequent development of splenomegaly and lymphoadenopathy. All animals succumbed to the leukemia within 24 to 30 days. Treatment of diseased animals with two courses of cytoxan over a 2-week period resulted in a remission period of approximately 16 to 18 days before relapse and eventual death of approximately 70% of the drug-treated animals. A significant number of long-term survivors (50 to 83%) was obtained in groups of animals that received combined drug plus BCG or C. parvum therapy. In contrast, the administration of MER (a methanol-extracted residue of BCG) to animals in a drug-induced remission period was no more effective than drug alone. The protective effect afforded by BCG and C. parvum was dependent on the time interval between drug therapy and the administration of the immunostimulators. Treatment of leukemic animals with BCG, C. parvum, or MER alone proved ineffective as all mice died at approximately the same time as untreated control animals. No leukemic cells were observed in any of the histologically examined tissues taken from long-term survivors. The implication of these results for cancer therapy is discussed.

A preliminary report on the effects of methanol extraction residue of BCG (MER) on cancer patients

Twenty-seven patients with malignant neoplasia were injected intradermally with the methanol extraction residue (MER) fraction of tubercle bacilli. Two schedules of treatment were used: every other week and once a month; 1-10 courses of MER were administered to the patients. The skin reactivity to 3 recall antigens, as well as to the injected MER itself, was used to monitor the immune response. Improvement of skin reactivity occurred in 9 of 18 patients tested with recall antigens. Five of 6 patients treated every other week improved in their immune capacity whereas only 4 of 12 patients improved on the monthly schedule. Thus, repeated injections given every other week were more effective in increasing the cutaneous reactivity than monthly injections of MER. The side-effects of MER treatment were tolerable.

Tumour inhibition mediated by BCG in immunosuppressed rats

Two rat sarcomas (CC5 and P7) which grow progressively on transplantation into normal syngeneic hosts failed to develop when injected in admixture with the Glaxo strain of Bacillus Calmette-Guérin (BCG). Under comparable conditions, the local development of a third neoplasm (P8) was temporarily inhibited and the number of pulmonary metastases significantly reduced. Experiments were undertaken to determine the extent to which the anti-tumor action of BCG required an immunocompetent host. Rats were immunosuppressed by sub-lethal whole-body irradiation (450 R), with or without prior thymectomy and challenged with inocula of mixed BCG and tumour cells when their capacity to respond to bacterial, tumour and unrelated antigens was maximally depressed. In non-sensitized immunosuppressed rats, the ability of BCG to limit tumour outgrowth was abrogated only in the case of sarcoma CC5. For this neoplasm, immunogenic in syngeneic hosts by conventional criteria, there was a statistically significant difference in the number of tumours in immunosuppressed rats (51%) compared with non-sensitized immunocompetent controls (6%). Presensitization to either bacterial or tumour antigens, prior to thymectomy and/or irradiation, fully restored the tumour-inhibitory capacity of BCG. By contrast, sarcoma P7 was not significantly less susceptible to BCG-induced regression in non-sensitized immunosuppressed rats than in nonsensitized normal rats; and sarcoma P8 similarly failed to reveal any significant differences in susceptibility to BCG affecting primary or secondary tumour development. It is concluded that tumours may vary widely in their sensitivity to host reactions aroused by BCG. Certain neoplasms, exemplified by sarcoma CC5, require participation of an immune reaction of delayed hypersensitivity type for optimal destruction at BCG sites, while for others (e.g. sarcoma P7) an immunoreactive component of this type is not essential. By contrast, a third category of tumour (e.g. sarcoma P8) is relatively resistant to host reactions induced by the mycobacteria. An important component of BCG-mediated tumour inhibition is not dependent on an immunologically intact host.

BCG-induced protection against malignant melanoma: possible immunospecific effect in a murine system

This report documents for the first time BCG-induced protection against a murine malignant melanoma. Adult Balb/C mice recieved 0.1-cm3 doses of BCG prior to intramuscular challenge with 1 x 10-6 S-91 melanoma cells. A 65% reduction in melanoma incidence was noted in BCG-pretreated mice. The possibility of specific protection induced by the BCG against the melanoma exists, since the BCG pretreatment did not protect against challenge with 1 x 10-5 mammary carcinoma cells or 1 x 10-4 MCA fibrosarcoma cells in the same strain of mice. Lack of immunogenicity was not a factor in the inability of the carcinoma and sarcoma to be inhibited by BCG. The strenght of the BCG-induced protection against the S-91 melanoma was demonstrated by significantly decreased tumor incidence following three different log challenge doses of the melanoma. However, reduction of the sarcoma challenge dose to as few as 10-2 cells administered to BCG pretreated mice did not result in decreased tumor incidence. It was further discovered that as few as two doses of 0.1 cm3 of BCG were sufficient to produce a 70% reduction in melanoma incidence compared with the incidence in control animals (P less than .001). Lymphocyte-mediated cytotoxicity studies paralleled the results of the in vivo experiments. Lymphocytes immune to each of the three tumors showed significant cytotoxicity against their respective tumor target cells (p less than .001), while the only tumor cells that lymphocytes from BCG-pretreated mice showed significant cytotoxicity against were S-91 target cells (p less than .01). Nonspecific cytotoxicity was not a factor in the effect of BCG-immune lymphocytes against S-91 target cells, since BCG-immune lymphocytes were not cytotoxic to Balb/C fibroblasts.