Cynthia Stanford

The use of mycobacterial adjuvant-based agents for immunotherapy of cancer

A heat-killed preparation of Mycobacterium vaccae (SRL172) has been shown, in recent studies, to be effective in the treatment of adenocarcinoma of the lung and renal cell cancer. It is postulated that the mechanisms of this form of immunotherapy is, at least in part, due to immune regulation, reflected in the selective enhancement of Th1 and down-regulation of Th2 T cell activity. These beneficial effects are attributed to the ability of adjuvants in the bacterial cell walls to modify and optimise the response to antigens shared by the bacteria and stressed host tissues, resulting in the destruction of cancer cells by programmed cell death or apoptosis. The M. vaccae-induced apoptosis appears to be most effective against carcinomas, perhaps especially those of glandular tissue, in contrast to pyrexia-induced necrosis which is most effective against tumours of mesodermal origin. In view of the great range of adjuvants, especially in the genus Mycobacterium and related genera, it may prove possible to develop a range of immunotherapeutic agents with useful activity against a wide range of cancers.

Clinical and serological studies of tuberculosis patients in Argentina receiving immunotherapy with Mycobacterium vaccae (SRL 172)

Two small, placebo-controlled studies of immunotherapy with heat killed Mycobacterium vaccae added to routine chemotherapy for pulmonary tuberculosis, together involving 40 HIV seronegative patients, were carried out in Argentina. The immunotherapy was associated with reduced sputum smear positivity of AFB at 1 month and a greater reduction in ESR at 2 months. In the first study radiological improvement was better (P < 0.05) among immunotherapy recipients. In the second study, weight regain and time to become apyrexial were measured and were found to be improved amongst immunotherapy recipients (P < 0.05). In the first month of treatment the levels of IgG to the 65 kDa and 70 kDa heat-shock proteins showed greater falls following immunotherapy (P < 0.05 and P < 0.001, respectively). On admission serum cytokine levels of interleukins 4 and 10 (IL-4, IL-10), interferon gamma (IFN-gamma) and tumour necrosis factor alpha (TNF-alpha) were grossly raised in comparison with a matched control group (P < 0.001). After 1 month. Levels of IL-4, IL-10 and TNF-alpha fell (P < 0.001, P < 0.01 and P < 0.01, respectively) and levels of IFN-gamma rose more (P = 0.005) in immunotherapy recipients than in those receiving chemotherapy alone. The results are in accord with a switch towards a TH1 immunological status and clinical benefit for immunotherapy recipients.

Immunotherapy with Mycobacterium vaccae in the treatment of tuberculosis in Romania. 2. Chronic or relapsed disease

In this study of 102 patients with culture-positive chronic treatment failure or repeatedly relapsed pulmonary tuberculosis receiving chemotherapy, 56 received an injection of killed Mycobacterium vaccae as immunotherapy after 1 month of treatment. At the start of treatment, there was little difference between those receiving immunotherapy and the 46 patients in the control group receiving chemotherapy alone. Thereafter, the two groups diverged so that 1 yr later, 43 of 56 (77%) patients receiving M. vaccae had a successful outcome, in comparison with 24 of 46 (52%) patients receiving chemotherapy alone (P < 0.02). Successful results were obtained from patients infected with drug-resistant bacilli, 20 of 32 (63%) patients compared with 11 of 25 (44%) patients, respectively, as well as from fully drug-sensitive cases (23 of 24 compared with 12 of 21 patients; P = 0.004). At the final follow-up after 22 months, 13 of 56 patients receiving immunotherapy had an unfavourable outcome compared with 26 of 46 members of the control group (P = 0.0006). During the study, 16 patients died of tuberculosis (six after immunotherapy), and 12 were lost to follow-up. Not only was bacteriological success improved by immunotherapy, chest X-ray showed markedly better resolution of cavities and other radiological lesions, recovery of body weight was improved, and the mean erythrocyte sedimentation rate returned almost to normal (P < 0.001) in comparison with those receiving chemotherapy alone. These changes were seen even in those failing bacteriological cure, suggesting that the immunotherapy had been effective, but that bacilli were replicating in an extracellular situation, protecting them from its effects.

Immunotherapy with Mycobacterium vaccae in the treatment of tuberculosis in Romania. 1. Newly-diagnosed pulmonary disease

In this study, 206 previously untreated patients with sputum culture positive pulmonary tuberculosis were randomized to receive an injection of killed Mycobacterium vaccae as immunotherapy, or of saline as placebo, after 1 month of a 6-month chemotherapeutic regime. Not surprisingly in a disease for which there is good chemotherapy, the difference in numbers which were culture negative at the end of treatment was small, and the final outcome at the latest post-treatment follow-up did not reach statistical significance between the two arms of the study. Nonetheless, those receiving immunotherapy showed better progression in every parameter measured, suggesting faster and more complete cure. Whereas seven of 97 patients receiving immunotherapy required a course of re-treatment and five still had active disease after a mean follow-up of 2 yr, 13 of 109 placebo recipients required re-treatment and nine still had active disease at the end of the study. Only one patient receiving M. vaccae plus chemotherapy died of tuberculosis, compared with four of those receiving chemotherapy alone. A degree of drug resistance was shown by the bacilli cultured from 25 of 175 (14%) patients, and seven of them (4.0%) were multi-drug resistant. Fourteen patients received immunotherapy of whom 13 were cured, including all three of those showing multi-drug resistance. Of the 11 patients with drug resistance in the control group, eight were cured, and one patient with multi-drug-resistant disease died of tuberculosis during re-treatment.

Immunotherapy of Tuberculosis with Mycobacterium vaccae NCTC 11659

The history of immunotherapy for tuberculosis is briefly reviewed, and the early appreciation of the importance of secreted antigens, common mycobacterial antigens and stress proteins is noted. The methods by which Mycobacterium vaccae strain NCTC 11659 was selected for special attention, and results of some of the pilot studies of its use as an immunotherapeutic for tuberculosis are reviewed. The results suggested that immunotherapy with M. vaccae may be an important step forward in the treatment and eventual control of tuberculosis. Used in combination with modern short course chemotherapy, treatment failures and deaths during treatment can be significantly reduced. Preliminary data suggests that shortened courses of chemotherapy may be possible when combined with immunotherapy, and such treatment may also be effective in patients co-infected with HIV. Studies at several centers show that M. vaccae may have an important part to play in the treatment of multi-drug resistant tuberculosis, especially when resistance is of the primary type. The mechanism by which M. vaccae achieves these results may be through adrenal endocrine influences on immunity, but remains speculative.

Immunotherapy for Tuberculosis

Modern immunotherapy for tuberculosis is designed to enhance antibacterial immunity and switch off the immune mechanism of tissue damage by promoting maturation of type 1 CD4+ and cytotoxic CD8+ ? lymphocytes, leading to destruction of intracellular bacilli. These intracellular organisms are the reason chemotherapy has to be so prolonged, and may be the persistent bacteria that are responsible for reactivation years after infection. Noncompliance with therapy is a major cause of failure of tuberculosis control and of increasing drug resistance, especially in the developing world. A combination of chemotherapy to kill rapidly metabolising extracellular bacilli and some intracellular organisms, with immunotherapy effective against slowly metabolising intracellular bacilli, should lead to fewer treatment failures and shorter treatment regimens. A suspension of heat-killed Mycobacterium vaccae NCTC 11659 has proved effective in pilot investigations. Randomised double-blind placebo-controlled studies have shown that a single injection of M. vaccae, given early in chemotherapy, halves treatment failure rates and reduces deaths during treatment. Even when M. vaccae had to be given with very inadequate chemotherapy, clinical condition and clearing of bacilli from the sputum were much improved. Promising results have been obtained in the treatment of multidrug-resistant tuberculosis, and in patients co-infected with HIV. Radical new approaches to the treatment of tuberculosis are badly needed, and although definitive trials have still to be completed, the evidence available suggests that immunotherapy with M. vaccae is a powerful and cheap addition to the treatment armamentarium.

Immunotherapy with oral, heat-killed, Mycobacterium vaccae in patients with moderate to advanced pulmonary tuberculosis

A research investigation to evaluate the potential of an oral preparation of Mycobacterium vaccae SRL172 (NCTC 11659) as an immunotherapeutic has been carried out in ten patients with moderate to advanced pulmonary tuberculosis at Carrasco Hospital, Argentina. Comparison was made between oral and injected M.vaccae sharing a mutual control group. Clinical, bacteriological, hematological, radiological and immunological assessments all showed comparable benefits for both injected and oral treatment over those achieved with chemotherapy alone. The only significant difference between results of injected and oral M.vaccae was the failure of the latter to reduce TNF-alpha production by cultured mononuclear cells. A more intensive regime for the oral preparation was used, which as an addition to the directly observed therapy, short-course, treatment should improve results in both drug susceptible and drug-resistant cases. A Phase II Good Clinical Practice trial is now required.

The common mycobacterial antigens and their importance in the treatment of disease.

The mycobacteria are one of a number of genera making up the aerobic Actinomycetales. Their antigens demonstrable by immuno-precipitation methods can be divided into four groups. The group i antigens, common to all mycobacterial species, cross-react with their counterparts in animal cells, largely derived from mitochondria. Notable amongst these antigens are the heat-shock, or stress, proteins and possibly bacterial sugars. Tests of cell-mediated immunity show that people can be separated by their responsiveness in skin-test, or lymphocyte proliferation techniques, into four categories of responders. Category 1 individuals respond to all mycobacterial reagents through recognition of the group i antigens. Many chronic diseases are associated with a lack of cell-mediated responsiveness to the group i antigens, and have a raised antibody titre to them. This reflects a predominance of T helper 2 activity and reduced T helper 1 responsiveness as part of the pathogenesis of their diseases, which include chronic bacterial, viral and parasitic infections, allergies, auto-immunities and neoplasms. Packaged together, the group i antigens and the cell-wall adjuvants of selected aerobic Actinomycetales make potent immuno-modulatory reagents. An example is heat-killed Mycobacterium vaccae, useful in both prevention and treatment of disease. Treatment with such reagents results in alleviation of disease, restoration of cellular responsiveness to the common mycobacterial antigens and a decrease in antibody titres to them. This new approach to treatment for such a wide range of diseases has few disadvantageous side effects and can accompany other non-immunosuppressive therapies.

Mycobacteria and their world

212-5 oi:10 * Cor E-m Investigational aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Skin-testing with tuberculins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 The antigens of mycobacteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Leprosy and tuberculosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Buruli ulcer—M. ulcerans disease. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Other mycobacterial diseases occurring in man . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 The Immuno-pathological spectrum of mycobacterial infections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 The Bacillus of Calmette and Guerin (BCG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Mycobacterium vaccae—an immunomodulator for prophylaxis and therapy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Mycobacterium vaccae in prophylaxis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Mycobacterium vaccae in therapy for leprosy and tuberculosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Unexpected findings with M. vaccae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Mycobacteria and cancer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Immune modulation and genera related to mycobacteria. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Tsukamurella inchonensis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Gordonia bronchialis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Successful immunotherapy of canine flea allergy with injected Actinomycetales preparations

AIMS Can heat-killed, borate-buffered suspensions of Gordonia bronchialis, Rhodococcus coprophilus or Tsukamurella inchonensis be used to treat canine flea allergy? MATERIALS & METHODS Organisms cultured on Sautons medium into stationary phase were autoclaved in borate-buffered saline and stored at 10 mg wet weight/ml. Intradermal injections of 0.1 ml containing 1 mg of bacilli were administered on the first and 20th days of the study. G. bronchialis and R. coprophilus were most effective in a pilot study of a small number of dogs with flea allergy. A larger number of affected dogs were then randomized to receive placebo or either of the two selected reagents. The extent and severity of allergic signs and symptoms were scored and blood samples were collected just before the first injection and 28 days after the second. RESULTS Both selected reagents reduced the extent and severity of lesions (p < 0.001) and reduced scratching. Eosinophil numbers were reduced (p < 0.0001) between the first and second assessment. CONCLUSIONS Injections of G. bronchialis or R. coprophilus effectively reduce the signs and symptoms of flea allergy in dogs.