Possibilities and problems of immunologic intervention in cancer

Cancer and the immune system

Early expectations for control of cancer through immunologic intervention are still unrealized. Increased knowledge of tumor immunity has broadened the understanding of the tumor and host relationship. This article reviews the evidence for an immune response to tumors, tumor antigens, immunologic intervention in cancer, insufficiency of the immune system to eliminate tumor growth, and immunologic approaches to the diagnosis of tumors.

Is cancer a macrophage-mediated autoaggressive disease?

As part of their physiological functions macrophages secrete various products that influence tissue environment. They can also secrete tumour growth promoting substances and it is highly probable that they help to establish tumour supporting fibrovascular stroma. Macrophages may fuse with other cells (including neoplastic cells) and many malignant properties of these hybrids or of their progeny may be maintained by the macrophage genome. In addition processes that occur after fusion might be important in inducing malignant transformation, especially when fusion has occurred with initiated cells. Superficial spreading melanoma is an example that is in keeping with the hypothesis of cell fusion.

Chemical of current interest--benzene

Benzene is one of the world's major commodity chemicals. It is derived from petroleum and coal and is used both as a solvent and as a starting material in chemical syntheses. The numerous industrial uses of benzene over the last century need not be recounted here, but the most recent addition to the list of uses of benzene is as a component in a mixture of aromatic compounds added to gasoline for the purpose of replacing lead compounds as anti-knock ingredients. The best known and longest recognized toxic effect of benzene is the depression of bone marrow function seen in occupationally exposed individuals. These people have been found to display anemia, leucopenia, and/or thrombocytopenia. When pancytopenia, i.e., the simultaneous depression of all three cell types, occurs and is accompanied by bone marrow necrosis, the syndrome is called aplastic anemia. In addition to observing this decrease in humans and relating it to benzene exposure, it has been possible to establish animal models which mimic the human disease. The result has been considerable scientific investigation into the mechanism of benzene toxicity. Although the association between benzene exposure and aplastic anemia has been recognized and accepted throughout most of this century, it is only recently that leukemia, particularly of the acute myelogenous type, has been related to benzene. The acceptance of benzene as an etiological agent in aplastic anemia in large measure derives from our ability to reproduce the disease in most animals treated with sufficiently high doses of benzene over the necessary time period. Unfortunately, despite extensive efforts in several laboratories, it has not been possible to establish a reproducible, reliable model for the study of benzene-induced leukemia. The recent demonstration that several animals exposed to benzene either by inhalation or in the drinking water during studies by Drs. B. Goldstein and C. Maltoni suggests that such a model may be forthcoming. Nevertheless, at this time it is not clear whether bone marrow damage of the type that leads to aplastic anemia is required for the development of leukemia. Most studies of benzene toxicity have involved dosing animals with benzene either by inhalation or by injection, using high doses to ensure a toxic response. Very few studies have concentrated on the oral route of administration and none have concentrated on administering benzene by mouth at the low doses occasionally detected in drinking water.(ABSTRACT TRUNCATED AT 400 WORDS)

Post operative stimulation of cell mediated immunity

The consequences of altered immuno-competence resulting from anaesthesia and surgery are potentially hazardous to the patient with malignant disease. Malnutrition also produces reduction in cell mediated immunity, a condition which is commonly incurred in patients with neoplastic disorders. Numerous agents have been claimed to stimulate the immune responses but few have proved to be of practical value. This paper reports the use variously of protease inhibitors, using Aprotinin, and post operative nutritional therapy, following major surgical resection for carcinoma - specifically as regards their influence on parameters believed to relate to cell mediated immunity. No clinical, metabolic or immunologic benefit was identified from either method of post operative stimulation of cell mediated immunity, although this study did confirm post operative depression of these parameters. The significance of these changes is unclear but there is no evidence to support an immunological mechanism for either of these approaches being of benefit in clinical practice.

Clinical studies on cell-mediated immunity in patients with malignant disease. I. Effect of immunotherapy with OK-432 on lymphocyte subpopulation and phytomitogen responsiveness in vitro

Immunotherapy with daily intradermal injections of OK-432, penicillin- and heat-treated lyophilized powder of Su-strain of streptococcus pyogens A3, for over a period of four weeks resulted in quantitative and qualitative effectiveness on impaired cell-mediated immunity even in many patients with far advanced cancer of the stomach or lung. In vitro lymphocyte studies following immunotherapy with OK-432 demonstrated restoration of circulating lymphocyte counts to more than 1,500/microliters, a level associated with normalized subpopulation constitution and increases of phytomitogen blastogenesis. Furthermore, a delayed hypersensitivity skin reaction to PPD was boosted or converted into a positive reaction in some cases. There was, however, no detectable, definite effect on humoral immunity after the therapy. Survival rates at three and six months after the initiation of immunochemotherapy using OK-432 and another chemotherapeutic agent, 5-fluorouracil, in 40 patients with cancer were significantly longer than those of matched control patients given chemotherapy alone.

Clinical uses of microorganisms and their products

Although antibiotics and conventional vaccines are the two most familiar examples of man's exploitation of microorganisms as clinical allies, microorganisms and their products are assuming an increasingly prominent role in the diagnosis, treatment and prevention of human diseases. This report attempts to give a brief overview of the status of the use of microorganisms in clinical medicine and to identify potentially fertile areas for future progress in their clinical application, concentrating on areas other than the already extensively reviewed ones of antibiotics and classic immunization.

Ovarian cancer: a solid tumor with evidence of normal cellular immune function but abnormal B cell function

Immunologic assays of B and T lymphocyte function were performed on 21 patients with epithelial ovarian cancer prior to either chemotherapy or radiotherapy. The results were compared to similar studies on 12 age-matched normal women. The total peripheral blood lymphocyte counts, proportion of E rosette positive cells, stimulation of T cells by phytohemagglutinin and concanavalin A, recall skin tests, and the ability to have a primary delayed hypersensitivity response to keyhold limpet hemocyanin did not differ between patients and controls. However, patients with ovarian cancer had statistically significant reduction in surface immunoglobulin positive cells, proliferative response to pokeweed mitogen and primary antibody response to keyhole limpet hemocyanin. In contrast to results in patients with other solid tumors, these data indicate that untreated patients with ovarian cancer have evidence of normal cellular immune function but abnormal B cell function.

Comparison of the effects of single versus multiple agent chemotherapy on lymphocytes assayed by the rosette technique

The percentage of peripheral blood Total T, Active T and B-Rosette Forming Cells (RFC) were determined serially (Day 0, 1, 2, 7, and 21) following administration of single (SAT) versus multiple (MAT) agent chemotherapy. SAT caused essentially a decrease in the percentage of B-RFC. MAT resulted in profound decrease of Active T and B-RFC and to a lesser degree of Total T-RFC percentages with nadirs being reached in 48 hours. The most striking decrease involved the percentage of Active T-RFC which remained 15% below pretreatment level 7th posttreatment day. The posttreatment changes in the absolute numbers of Total T, Active T and B-RFCs following MAT were similar to that noted on the RFC percentage. Effects of the two most commonly used multiple agent treatments (COBAM and DOMF) were comparable. MAT causes a more profound decrease in the percentage of various RFCs than SAT. The differences between the nadirs of various RFC reached Day 1 and 2 with MAT versus SAT are statistically significant (p less than .001). We conclude that the effects of chemotherapy on peripheral RFC may be best evidenced by serial determination of their percentage rather than their absolute numbers. Subpopulation of the T-RFC which has been labeled Active T-RFC appears to be the best indicator of the chemotherapy effects on the lymphocyte population since they demonstrate the most profound and persistent changes.

Lymphocyte cytotoxicity in the X-irradiation induced rat small bowel adenocarcinoma. II. Presence of cytotoxic lymphocytes in irradiated animals

Cytotoxic peripheral blood lymphoid cells were demonstrated in both Holtzman and Lewis Brown-Norway rats which had received 2000R of local X-irradiation to the temporarily hypoxic, exteriorized, ileum and jejunum regardless of whether a small bowel adenocarcinoma subsequently developed. The cytotoxic response, which was detectable at two days, was quite evident by day 5 post-irradiation. No evidence of cross-reacting tumor antigens was obtained when similarly processed effector cells from Holtzman rats bearing a spontaneous mammary carcinoma were incubated with cell cultures derived from the small bowel adenocarcinoma. These findings indicate X-irradiation of the small bowel initiates lymphocyte sensitization that is manifested as in vitro cytotoxicity against cell cultures of the adenocarcinoma.

Adjuvant treatment with levamisole in cancer: a review of experimental and clinical data

Animal and human studies of adjuvant treatment with levamisole in cancer are reviewed and discussed. From the animal data it is concluded that the activity of levamisole is dose-dependent, more effective on slow-growing tumors, affects metastasis formation, preferentially is best when levamisole is used as an adjuvant to the usual cytoreductive treatments and that tumor enhancement is not expected. Clinical findings are put into perspective of the animal data and the most appropriate clinical situations are indicated.

The role of IgE in the immune response to neoplasia: a review

The role of IgE in the immune response to neoplasia has received little attention despite suggestive evidence for an IgE response to tumor specific antigens. A complex interrelationship is known to exist between basophils, eosinophils, histamine, complement, and T cells. The latter cells are known to play a central role in the immune response to neoplasia and, in addition, are now considered important in the production and regulation of IgE, the molecule that may supply an important link between pharmacological and cellular dynamics of a successful anti-tumor response. The evidence for an IgE role in the immune response to tumors, the relationship between atopy and cancer, and the possible mechanisms whereby IgE could enhance tumor rejection are discussed in this review.

The influence of nonspecific immunotherapy on the course of murine melanoma

BCG, Corynebacterium parvum, vitamin A, and levamisole were continuously administered to C57 BL/6 mice bearing B16 melanoma prior to, with following tumor implantation as well as before and coincident with surgical excision of the implanted tumor. Only the group given levamisole prophylactically for 8 weeks before tumor inplantation showed a significant difference from control mice but a tenfold increase in dosage in this drug did not exert a comparable effect.

An immunologic approach to tumor imaging

There seems little doubt that the ability to prepare antibodies with a unique specificity for surface tumor antigens will have a tremendous usefulness in the diagnostic and therapeutics of cancer. This usefulness will be wide-ranged when the antibodies are labeled with radioisotopes as tools for screening for primary lesions to determine the presence and location of metastases. Therapeutically, such preparations can be used to deliver high doses of radiation to specific areas, as carriers of chemotherapeutic drugs, as well as take advantage of the intrinsic cytotoxicity of such materials. The major problem preventing general application is the production and purification of the tumor-specific antigen which can be used to prepare subsequent reactive antisera. Intensive efforts are going on into research in this area as well as the preparation and problems inherent with using specific antibodies on a diagnostic and therapeutic basis. Present research indicates that the former problem may be resolved reasonably soon and it is felt that this will lead to successful diagnostic and therapeutic tools. The various studies and problems are presented in this review in relation to their ultimate potential clinical usefulness.

Feasibility study of active immunotherapy in patients with solid tumors

Forty-five immunocompetent patients with solid tumors were immunized with BCG, PPD, and tumor cells. The methods were practical, but the morbidity was significant, including painful draining ulcerations at vaccine sites, possible enhancement of tumor growth in three patients, and the discovery at autopsy of systemic tuberculosis in one patient. Various facets of cellular immunity were altered, namely: 1) a majority of the patients developed enhanced cutaneous reactions to the microbial skin-test antigens (particularly tuberculin) and tumor cells; 2) nine patients developed the equivalent of delayed hypersensitivity reactions or flares at all previous PPD and BCG inoculation sites following subsequent injection of these agents, which supports the concept of immunologic memory for these target antigens; 3) lesions resembling those of "spontaneous" regressed moles (halo-nevi) were observed at previous vaccine sites in 20 patients and generalized depigmentation occurred in three patients; 4) foreign body giant cells in tumor metastasis remote from BCG-PPD-tumor vaccine sites may indicate a cross-reactivity of microbial and tumor antigens; and 5) intralesional inoculation of the nonspecific agents (BCG, PPD, Varidase, and Mumps) resulted in dense mononuclear cell infiltration and complete regression of most of the injected lesions. Destruction of single or multiple lesions by local injections of antigens did not provide either significant regression of uninjected lesions or clinical benefit.

Human colonic adenocarcinoma cells. I. Establishment and description of a new line

A series of human colonic epithelial cell lines have been cultured from a single patient: LS-180 the original adenocarcinoma, LS-174T a trypsinized variant, and normal colonic tissue. The malignant cells, 20 to 40, mum in diameter and oval to polygonal, exhibited characteristics of normal colonic mucosal cells, namely, abundant microvilli prominent in secretory cells, and the presence of intracytoplasmic mucin vacuoles. The cultured adenocarcinoma cells, but not normal, demonstrated neoplastic properties by producing high levels of carcinoembryonic antigen (CEA) and by the ability to be propagated in hamster cheek pouches and in immunodeprived mice. The CEA production by the newly established line LS-180 released 900 times more CEA per cell into the culture medium and bore 30 times more cell-associated material than the established line, HT-29. These cell lines may permit detection of distinctive chemical, physiological, pharmacologic, and immunologic characteristics of neoplastic colonic cells.

Neuraminidase immunotherapy: serum potentiation of lymphocyte cytotoxicity related to immunoglobulin levels

Seven patients completed couses of immunotherapy using neuraminidase-altered autochthonous cells. Their response to therapy was monitored by a cytotoxicity assay using 3H-proline-tagged tumor cells from the patient's own cultured tumor in a strictly autologous system. Serum effects were measured by exposing the tumor target cells to serum to see whether this impeded (blocked) or augmented (potentiated) lymphocyte cytotoxicity. Three of the seven patients developed increasing degrees of serum blocking effect and all died within six months of completing therapy. Four of the seven showed rapidly decreasing blocking and three eventual potentiation. Three patients are living, improved, and free of evidence of tumor. There was an increase in average serum immunoglobulins in patients developing potentiation, and a decrease in those showing blocking. In any immunotherapy program attention must be given to in vitro monitoring studies, and such studies should include attention to the serum factors influencing host response.

Thymosin-induced increase in E-rosette-forming capacity of lymphocytes in patients with malignant neoplasms

Thymosin, a thymic hormone, restores decreased cellular immunity under various experimental conditions. The purpose of this study was to evaluate the effect of thymosin on the E-rosette-forming capacity in cancer patients. Peripheral blood lymphocytes obtained from eight patients with various malignant neoplasms were examined. One of these patients received thymosin intramuscularly; his E-rosette formation was examined serially. Eight normal adults served as controls. Patients with advanced stages of malignant tumors showed decreased E-rosette-forming capacity, which increased significantly under the influence of thymosin. Patients with less-advanced tumors, as well as normal adults, demonstrated normal E-rosette formation without further effects by thymosin. The in vivo administration of thymosin to one patient was followed by a marked increase of the E-rosette-forming capacity. These results suggest that the administration of thymosin, both in vivo and in vitro, significantly increases the circulating T-lymphocyte levels and/or functions in patients with advanced malignant neoplasms.

A relationship between impaired cellular immunity humoral suppression of lymphocyte function and severity of systemic lupus erythematosus

Eighteen newly diagnosed, untreated patients with systemic lupus erythematosus (SLE) were divided into two groups based on the severity of the disease. Patients with very active disease were nonresponsive to skin test antigens used to assess delayed hypersensitivity. Skin test reactivity was intact in most patients with mildly active disease. Lymphocytes from subjects in both groups responded normally to phytohemagglutinin (PHA) when the results were expressed as counts per minute per million small lymphocytes. Serum from patients with severely active disease markedly suppressed lymphocyte responsiveness of autologous and allogeneic lymphocytes. Serum from patients with mild disease had significantly less suppressor activity. Lymphocytotoxic antibodies and suppressor activity were not correlated. Suppressor activity in immunoglobulin G fraction paralleled that found in whole serum. The present studies suggest that impaired delayed whole serum. The present studies suggest that impaired delayed hypersensitivity in SLE is a consequence of disease activity rather than an inherent feature of this disease. The strong correlation between serum suppression of PHA reactivity and anergy suggests that the humoral immunosuppressive effects described may be responsible, in part, for impaired delayed hypersensitivity in this disease.

Elevated IGA in carcinoma of the nasopharynx

Fourteen patients with nasopharyngeal carcinoma were evaluated immunologically prior to standard radiotion therapy. All had elevations of serum IgA, ranging from 300 mg/100 ml to 1000 mg/100 ml, with a mean value of 549 mg/100 ml. Seven patients demonstrated depression of cell-mediated immunity as measured by delayed hypersensitivity skin tests, total lymphocyte count, in vitro stimulation with PHA, and T-cell rosette formation. Elevation of serum IgA associated with depression of cell mediated immunity may be characteristic of patients with nasopharyngeal carcinoma.

Osteogenic sarcoma. Immunologic parameters before and during immunotherapy with tumor-specific transfer factor

18 patients with osteogenic sarcoma were followed by serial measurements in vitro of tumor-specific cell-mediated cytotoxicity and of "active" and total rosette-forming T-cells. 13 of these patients have had or are currently receiving injections of osteogenic sarcoma-specific dialyzable transfer factor derived from healthy donors. In three patients with very small lesions, cytotoxicity was high before amputation and decreased within 2 mo after removal of tumor. Cytotoxicity was low at time of diagnosis in all patients with large tumor masses. The cytotoxicity of the patients' lymphocytes increased after administration of tumor-specific transfer factor in all patients so treated. Patients receiving nonspecific transfer factor showed evidence of declining cell-mediated cytotoxicity. Tumor-specific transfer factor may produce an increase in cell-mediated cytotoxicity to the tumor in patients with osteogenic sarcoma. This possibility is suggested by the pain and edema that occurred in the area of the tumor in patients who had metastatic disease when therapy was started and by lymphocytic infiltrates in the tumor, as well as by the increase in cell-mediated cytotoxicity and the increase in percentage of active rosette-forming cells from subnormal to normal. Serial measurements of cell-mediated cytotoxicity are helpful in monitoring the efficacy of transfer factor and other modes of therapy in these patients, and these measurements are the best available criteria for selection of donors of tumor-specific transfer factor.

Evidence of suppressor cell activity in spleens of mice bearing primary tumors induced by Moloney sarcoma virus

Spleens from Moloney sarcoma virus (MSV) tumor-bearing C57BL/6N mice contained four times the normal number of mononuclear cells and displayed a markedly elevated "spontaneous" (mitogen-independent) DNA synthesis on a per cell basis. The number of macrophages were increased three-fold while there was a slight reduction in the percentage of T lymphocytes. The phytohemagglutinin (PHA) response on a per cell basis of spleens from tumor-bearing mice was decreased about 90% when compared with normal control mice. The primary in vitro immune response to sheep red blood cells was also suppressed to levels of less than 10% of normals. The PHA response could be restored by purification of MSV spleen cells by rayon adherence columns and by removal of phagocytic cells by an iron/magnet technique. The activity of suppressor cells in MSV spleens was demonstrated in mixtures with syngeneic normal spleen cells where a marked impairment of the PHA response was observed. Spleen cells from tumor-free nude mice and normal spleen cells treated by anti-theta serum plus guinea pig complement (C'), both totally unreactive to PHA, had no such effect. The inhibitor cell in MSV spleens was shown to be insensitive to inactivation by anti-theta plus C', but could be removed by the adherence columns and the iron/magnet technique. These data suggest that this suppressor cell is a cell of the monocyte/macrophage series. Suggestive evidence was also presented that the suppressor cells belong to a proliferating population in MSV spleens. Similar suppressor cells have been previously demonstrated in spleens of mice during a variety of immune responses. Our data show, that a tumor, although stimulating the immune system, nevertheless may be suppressive on certain immune functions through the activation of suppressor cells.