Helper strategy in tumor immunology: expansion of helper lymphocytes and utilization of helper lymphokines for experimental and clinical immunotherapy

Immunosuppressive activity of a cycloartane triterpene glycoside from Beesia calthaefolia by inhibiting T cell proliferation

BC-1 is a cycloartane triterpene glycoside isolated from the whole plant of Beesia calthaefolia. Our recent studies proved that BC-1 inhibited proliferation of splenic lymphocyte and phagocytosis of macrophages, and inhibited the increased production of TNF-α and IL-1β. However, it lacks of study about the immunomodulatory effect of BC-1 on purified T lymphocytes. Therefore, in the present study, we evaluated the suppressive potentials of BC-1 on immune responses in vitro. BC-1 markedly suppressed anti-CD3/CD28 mAbs (mAbs) induced murine T lymphocytes proliferation, the expression levels of CD69 and CD25 of CD3⁺ T cells. BC-1 could strongly decrease ratio of CD4⁺/CD8⁺, decrease the Th1/Th2 cytokines production (IL-2, IFN-γ, IL-4, and IL-10) of CD4⁺ T-cells. In addition, we studied signal transduction pathways about T-cell activation on puried murine CD4⁺ T lymphocytes by western-blot assay. The data revealed that BC-1 could inhibit the activation of JNK, ERK and PI3K/AKT signal transduction pathways. These results indicated that BC-1 possesses potential downregulating effect on the immune system and might be developed as an immunosuppressive agent in treatment of CD4⁺ T cell-mediated inflammatory and undesired immune responses.

Novel GM-CSF-based vaccines: One small step in GM-CSF gene optimization, one giant leap for human vaccines

Granulocyte macrophage-colony stimulating factor (GM-CSF) is a potent immunomodulatory cytokine that is known to facilitate vaccine efficacy by promoting the development and prolongation of both humoral and cellular immunity. In the past years we have generated a novel codon-optimized GM-CSF gene as an adjuvant. The codon-optimized GM-CSF gene significantly increased protein expression levels in all cells tested and helped in generating a strong immune responses against HIV-1 Gag and HPV-associated cancer. Here, we review the literature dealing with the adjuvant activity of GM-CSF both in animal models and clinical trials. We anticipate that the codon-optimized GM-CSF gene offers a practical molecular strategy for potentiating immune responses to tumor cell-based vaccinations as well as other immunotherapeutic strategies.

Dual Role of GM-CSF as a Pro-Inflammatory and a Regulatory Cytokine: Implications for Immune Therapy

Granulocyte macrophage colony stimulating factor (GM-CSF) is generally recognized as an inflammatory cytokine. Its inflammatory activity is primarily due its role as a growth and differentiation factor for granulocyte and macrophage populations. In this capacity, among other clinical applications, it has been used to bolster anti-tumor immune responses. GM-CSF-mediated inflammation has also been implicated in certain types of autoimmune diseases, including rheumatoid arthritis and multiple sclerosis. Thus, agents that can block GM-CSF or its receptor have been used as anti-inflammatory therapies. However, a review of literature reveals that in many situations GM-CSF can act as an anti-inflammatory/regulatory cytokine. We and others have shown that GM-CSF can modulate dendritic cell differentiation to render them "tolerogenic," which, in turn, can increase regulatory T-cell numbers and function. Therefore, the pro-inflammatory and regulatory effects of GM-CSF appear to depend on the dose and the presence of other relevant cytokines in the context of an immune response. A thorough understanding of the various immunomodulatory effects of GM-CSF will facilitate more appropriate use and thus further enhance its clinical utility.

GP96 C-terminal improves Her2/neu DNA vaccine

BACKGROUND

DNA vaccines ensure protective immunity against tumors in a variety of experimental models. The favorite target tumor-associated antigens have been those that are frequently expressed by human tumors, such as Her2. However, the efficacy of active vaccination is limited because Her2 is a self-tolerated antigen. Many strategies have been applied to increase the efficacy of DNA vaccination, such as fusion or co-administration of Her2 with cytokine and co-stimulatory molecules. GP96 is involved in innate and adaptive immune responses and evokes potent activation and maturation of dendritic cells along with increased secretion of pro-inflammatory cytokines. On the basis of previous studies, we expected the C-terminal of GP96 to act as a package and as a suitable substitute for both cytokine and co-stimulatory genes.

METHODS

In the present study, the C-terminal of GP96 fused or co-administered with Her2/neu-containing constructs was used and the resultant immune response was evaluated and compared.

RESULTS

The data obtained showed that the construct containing the C-terminal of GP96 fused with Her2/neu, but not the co-administration of the two separated constructs, decreased CD4(+)CD25(+)foxp3(+) regulatory T cells at the tumor site, enhanced cytotoxic T lymphocyte activity and increased interferon-gamma secretion.

CONCLUSIONS

The C-terminal of GP96 has potent adjuvant activity in eliciting a significant immune response when fused with Her2/neu. It may be used as molecular adjuvant along with other tumor or bacterial/viral antigens.

Cytokine gene transfer for cancer therapy

The possibility of inducing a strong immune response to impair tumor growth by ectopically expressing cytokines, followed by the generation of an antitumor memory raised great hopes and enthusiasm as a therapeutic approach. However, the efficacy of this strategy on established tumor models appeared low and the initial results in the clinics were disappointing. Recently, new evidence indicates that cytokine gene combination or the combined use of cytokine genes with additional gene therapy approaches induces a synergistic effect supporting the use of cytokine gene therapy to improve the clinical outcome for cancer patients.

Combinatorial Cancer Immunotherapy

The formulation of therapeutic strategies to enhance immune-mediated tumor destruction is a central goal of cancer immunology. Substantive progress toward delineating the mechanisms involved in innate and adaptive tumor immunity has improved the prospects for crafting efficacious treatments. Schemes under active clinical evaluation include cancer vaccines, monoclonal antibodies, recombinant cytokines, and adoptive cellular infusions. While these manipulations increase tumor immunity in many patients, the majority still succumbs to progressive disease. Detailed analysis of subjects on experimental protocols together with informative studies of murine tumor models have begun to clarify the parameters that determine therapeutic activity and resistance. These investigations have highlighted efficient dendritic cell activation and inhibition of negative immune regulation as central pathways for intervention. This review discusses the development of genetically modified whole tumor cell vaccines and antibody-blockade of cytotoxic T lymphocyte associated antigen-4 (CTLA-4) as immunotherapies targeting these key control points. Early-stage clinical testing raises the possibility that combinatorial approaches that augment dendritic cell-mediated tumor antigen presentation and antagonize negative immune regulation may accomplish significant tumor destruction without the induction of serious autoimmune disease.

Cytokines in cancer immunity and immunotherapy

The concept that the immune system recognizes and controls cancer was first postulated over a century ago, and cancer immunity has continued to be vigorously debated and experimentally tested. Mounting evidence in humans and mice supports the involvement of cytokines in tumor initiation, growth, and metastasis. The idea that the immune system detects stressed, transformed, and frankly malignant cells underpins much of the excitement currently surrounding new cytokine therapies in cancer treatment. In this review, we define the contrasting roles that cytokines play in promoting tumor immunity, inflammation, and carcinogenesis. We also discuss the more promising aspects of clinical cytokine use in cancer patients.

Electroporated DNA Vaccine Clears Away Multifocal Mammary Carcinomas in Her-2/neu Transgenic Mice

The transforming rat Her-2/neu oncogene embedded into the genome of virgin transgenic BALB/c mice (BALB-neuT) provokes the development of an invasive carcinoma in each of their 10 mammary glands. i.m. vaccination with DNA plasmids coding for the extracellular and transmembrane domains of the protein product of the Her-2/neu oncogene started when mice already display multifocal in situ carcinomas temporarily halts neoplastic progression, but all mice develop a tumor by week 43. By contrast, progressive clearance of neoplastic lesions and complete protection of all 1-year-old mice are achieved when the same plasmids are electroporated at 10-week intervals. Pathological findings, in vitro tests, and the results from the immunization of both IFN-gamma and immunoglobulin gene knockout BALB-neuT mice, and of adoptive transfer experiments, all suggest that tumor clearance rests on the combination of antibodies and IFN-gamma-releasing T cells. These findings show that an appropriate vaccine effectively inhibits the progression of multifocal preneoplastic lesions.

Restimulation of tumour-specific immunity in a patient with AML following injection with B7-1 positive autologous blasts

Leukaemic blast cells lack co-stimulatory molecules such as B7, necessary for T-lymphocyte activation. We have used modified CD80+ (B7-1+) tumour cells, with autologous, IL-2 producing, stromal marrow cells in a series of subcutaneous vaccinations to provide a localised environment for the enhancement of cytotoxic T-lymphocytes (CTL) in a patient with acute myeloid leukaemia (AML). Localised inflammation was evident after the fifth and sixth injections with a reduction in the number of circulating blasts in the following 2 weeks. Peripheral blood in vitro CTL activity increased 36-47% after five injections.CD4 T-lymphocytes (5.7%) expanded from post-injection skin biopsies, expressed intracellular IFNgamma and perforin when exposed to autologous B7-1+ blasts and when co-cultured with either B7-1+ or unmanipulated autologous blast cells showed proliferative responses. In this patient, co-injection of B7-1+ tumour cells, together with a local source of sustained IL-2, resulted in an autologous anti-leukaemic in vitro immune response.

GM-CSF-secreting melanoma vaccines

The development of biochemical and genetic schemes to characterize cancer antigens led to the recognition that malignant melanoma frequently evokes a host response. While the generation of brisk T-cell infiltrates in early stage disease is correlated with prolonged survival, host reactions in most cases are insufficient to impede tumor progression. One variable that may limit the potency of the host response against nascent melanoma is the mixture of cytokines present in the tumor microenvironment. In a murine melanoma model, we identified granulocyte-macrophage colony stimulating factor (GM-CSF) as the most potent molecule for augmenting tumor immunity following gene transfer into melanoma cells. Vaccination with irradiated melanoma cells engineered to secrete GM-CSF enhances host responses through improved tumor antigen presentation by recruited dendritic cells and macrophages. Melanoma-specific CD4(+) and CD8(+) T-cells, CD1d-restricted NKT-cells, and antibodies mediate tumor rejection. Initial testing of this immunization strategy in patients with metastatic melanoma revealed the consistent induction of cellular and humoral antitumor responses that provoked the extensive necrosis of distant metastases without significant toxicity.

Nonredundant roles of antibody, cytokines, and perforin in the eradication of established Her-2/neu carcinomas

Since the mechanisms by which specific immunity destroys Her-2/neu carcinoma cells are highly undetermined, these were assessed in BALB/c mice vaccinated with plasmids encoding extracellular and transmembrane domains of the protein product (p185(neu)) of the rat Her-2/neu oncogene shot into the skin by gene gun. Vaccinated mice rejected a lethal challenge of TUBO carcinoma cells expressing p185(neu). Depletion of CD4 T cells during immunization abolished the protection, while depletion of CD8 cells during the effector phase halved it, and depletion of polymorphonuclear granulocytes abolished all protection. By contrast, Ig mu-chain gene KO mice, as well as Fcgamma receptor I/III, beta-2 microglobulin, CD1, monocyte chemoattractant protein 1 (MCP1), IFN-gamma, and perforin gene KO mice were protected. Only mice with both IFN-gamma and perforin gene KOs were not protected. Although immunization also cured all BALB/c mice bearing established TUBO carcinomas, it did not cure any of the perforin KO or perforin and IFN-gamma KO mice. Few mice were cured that had knockouts of the gene for Ig mu-chain, Fcgamma receptor I/III, IFN-gamma, or beta-2 microglobulin. Moreover, vaccination cured half of the CD1 and the majority of the MCP1 KO mice. The eradication of established p185(neu) carcinomas involves distinct mechanisms, each endowed with a different curative potential.

GM-CSF-based cancer vaccines

The crafting of genetic and biochemical techniques to identify cancer antigens yielded the unexpected discovery that immune recognition of tumors regularly accompanies cancer development. The failure of the host to suppress tumor formation or attenuate disease progression may thus reflect the limited immunogenicity of nascent tumors. One critical determinant of host immunity is the mixture of cytokines produced in the tumor microenvironment. We have compared a large number of secreted and surface molecules for their relative abilities to augment tumor immunity following gene transfer into cancer cells. In multiple murine models, granulocyte-macrophage colony stimulating factor (GM-CSF) proved to be the most potent immunostimulatory product. Vaccination with irradiated tumor cells engineered to secrete GM-CSF involves enhanced tumor antigen presentation by recruited dendritic cells (DCs) and macrophages; the coordinated functions of CD4+ and CD8+ T cells, CD1d-restricted NKT cells and antibodies mediate protective immunity. The evaluation of this vaccination strategy in patients with advanced melanoma revealed the consistent induction of cellular and humoral antitumor responses capable of effectuating substantial necrosis of distant metastases. The formulation of simplified methods for manufacturing autologous, GM-CSF-secreting tumor cells has enabled more extensive clinical testing in diverse patient settings.

Vaccines in oncology: background and clinical potential

Cancer is one of the leading causes of death in Western society. Despite improvements in screening, diagnosis and treatment of cancer, many patients ultimately succumb to their disease. Advances in molecular biology and our increased understanding of how the immune system functions have led to an intense interest in the development of cancer vaccines.

Malignancy: Gene Therapy Vaccines in Acute Myeloid Leukemia : A Need for Clinical Evaluation

In the last decade our understanding of the processes that govern cell growth and differentiation, malignant transformation, and metastasis has become quite sophisticated. These new insights have revolutionized our ability to diagnose and to formulate prognoses for patients with cancer, and have inspired the design and development of novel therapeutic strategies that are based on modern gene-transfer technologies and act at the gene level. Gene therapy, broadly defined as the introduction of genetic material (transgenes) into a patient's cells with an intent to confer a therapeutic benefit, represents the most direct application of recombinant DNA technology in the clinical setting. The challenging concept of modifying the genetic properties of human cells captivated very quickly the interest of clinical and molecular oncologists, and currently, numerous gene therapy clinical trials in cancer patients are under investigation worldwide. Most of these studies involve manipulating the patient's immune response to tumors. The identification of tumor-specific antigens stimulating humoral and cellular responses in cancer patients, together with a better understanding of the molecular mechanisms controlling T cell activation have dramatically accelerated the search for potent cancer vaccines. In this review, we highlight important principles of cancer immunity and cancer vaccines, we discuss critical features of genetic manipulation of tumor cells, and particularly focus on preclinical studies on gene therapy vaccines in acute myeloid leukemia (AML).

Interleukin-12 gene therapy vaccines: directing the immune system against minimal residual leukemia

Current overall survival rates for patients with AML remain poor and there is need for novel therapeutic approaches. One such approach is to use the patient's own immune system to eliminate minimal residual disease. Recent advances in genetic manipulation of tumor cells, together with a better understanding of the immune mechanisms controlling the host-tumor relationship have led to a flurry of preclinical and clinical studies on tumor cell vaccines. Here we present a brief overview of genetic manipulation of tumor cells, and highlight important principles of cancer immunity and cancer vaccines. Special emphasis is given on recent work on the role of interleukin-12 (IL-12) based vaccines in murine AML. These studies have shown that vaccines with AML cells, genetically modified to secrete IL-12, are potent stimulators of the immune system and lead to the development of both prophylactic and therapeutic anti-leukemia immunity.

Cytokine-secreting tumor cell vaccines

Modification of the tumor microenvironment with gene transfer techniques stimulates two immune mechanisms that effectuate tumor destruction. One involves improved tumor-antigen presentation for the development of specific cellular and humoral immunity. The second involves compromise of the tumor vasculature by soluble factors and leukocytes.

Tumor rejection and immune memory elicited by locally released LEC chemokine are associated with an impressive recruitment of APCs, lymphocytes, and granulocytes

The human beta chemokine known as LEC (also called NCC-4, HCC-4, or LMC) displays chemotactic activity for monocytes and dendritic cells. The possibility that its local presence increases tumor immunogenicity is addressed in this paper. TSA parental cells (TSA-pc) are poorly immunogenic adenocarcinoma cells that grow progressively, kill both nu/nu and syngeneic BALB/c mice, and give rise to lung metastases. TSA cells engineered to release LEC (TSA-LEC) are still able to grow in nu/nu mice, but are promptly rejected and display a marginal metastatic phenotype in BALB/c mice. Rejection is associated with a marked T lymphocyte and granulocyte infiltration, along with extensive macrophage and dendritic cell recruitment. NK cells and CD4+ T lymphocytes are uninfluential in TSA-LEC cell rejection, whereas both CD8+ lymphocytes and polymorphonuclear leukocytes play a major role. An antitumor immune memory is established very quickly after rejection, since 6 days later 75% of BALB/c mice were already resistant to a TSA-pc challenge. Spleen cells from rejecting mice display specific cytotoxic activity against TSA-pc and secrete IFN-gamma and IL-2 when restimulated by TSA-pc. The ability of LEC to markedly improve recognition of poorly immunogenic cells by promoting APC-T cell cross-talk suggests that it could be an effective component of antitumor vaccines.

Interactions between autologous CD4+ and CD8+ T lymphocytes and human squamous cell carcinoma of the head and neck

The autotumor (AuTu)-specific cytolytic T lymphocyte (CTL) line established from the peripheral blood of a patient with oral squamous cell carcinoma (Cancer Res. 53, 1461, 1993) contained >95% of CD8+ and <5% of CD4+ T cells. This CTL line was infected with Herpesvirus saimiri to increase its life span in culture. Two transformed T cell sublines were obtained: the monoclonal CD4+ line (TCR Vbeta2+ V alpha15+) and the oligoclonal CD8+ line (TCR Vbeta6+, Vbeta7+ and Vbeta9+) both of which were maintained in culture for >6 months without AuTu restimulation and which did not produce any virus. The virus-transformed and untransformed T cell lines were compared for phenotypic and functional characteristics, including the ability to kill AuTu, induce expression of the major histocompatibility complex (MHC) antigens on AuTu, and respond to AuTu by cytokine production and/or proliferation. The H. saimiri-transformed CD4+ T cells expressed higher levels of surface adhesion molecules and CD45RO than untransformed cells and lysed AuTu by inducing DNA fragmentation as well as necrosis. This lysis was inhibited by antibodies to CD4 but not to class I or II MHC molecules. The CD4+ T cells produced IL2, TNF-alpha, and GM-CSF and proliferated in response to AuTu. They induced and sustained proliferation of CD8+ T cells in cocultures with AuTu. Supernatants obtained from cocultures of the CD4+ T cells with AuTu also induced proliferation of the CD8+ T cell line. In contrast, the H. saimiri-transformed CD8+ T cells did not kill AuTu or release cytokines in response to AuTu. However, upon pretreatment of AuTu with IFN-gamma to increase expression of MHC antigens, these T cells regained the ability to recognize and kill AuTu targets. Coincubation of AuTu with the CD4+ or CD8+ T cells significantly augmented expression of class I and II MHC antigens on AuTu. These data indicate that H. saimiri-transformed tumor-reactive T cell lines provide a useful model of interactions between immune effector cells and AuTu, and that CD4+ T cells play a critical role in the regulation of immune responses to squamous cell carcinoma of the head and neck.

Immune response to polyvalent melanoma cell vaccine in AJCC stage III melanoma: an immunologic survival model

BACKGROUND

Our polyvalent, allogeneic melanoma cell vaccine (MCV) induces immunoglobulin M (IgM) and immunoglobulin G (IgG) class antibodies to a 90-kDa glycoprotein melanoma-associated antigen (MAA). Additionally, MCV induces delayed-type hypersensitivity (DTH) responses that we previously correlated with survival. We hypothesized that early DTH responses to MCV and early humoral responses to the 90-kDa MAA expressed on MCV cells may be predictive of overall survival. We tested this hypothesis by monitoring immunologic profiles in 59 patients with melanoma who were receiving MCV after surgical resection of regional lymph node or soft-tissue metastases.

METHODS

Blood was drawn before vaccine administration, biweekly for 6 weeks, and then monthly. DTH to MCV was recorded at 0, 2, 4, and 8 weeks of MCV therapy. Mean antibody titers during the first 6-week interval were calculated. Changes in DTH were calculated as the difference between peak and prevaccine values (delta DTH).

RESULTS

At a median follow-up of 75.6 months (range 5-138), univariate analysis assigned prognostic significance to gender (p = 0.046), lymph node involvement (p = 0.024), delta DTH (p = 0.044), mean anti-90-kDa MAA IgG (p = 0.0009), and mean anti-90-kDa MAA IgM (p = 0.0014). In multifactorial analysis, only the three immunologic variables significantly impacted survival (p = 0.046, 0.0005, and 0.0053, respectively). A mathematical model based on delta DTH and mean anti-90-kDa MAA IgG and IgM titers closely approximated the observed individual and overall survival rates.

CONCLUSIONS

The correlation between overall survival and initial humoral/cellular immune responses to MCV immunotherapy may be useful in selecting patients most likely to benefit from prolonged adjuvant immunotherapy.

Correlation between clinical response and urinary interleukin levels using different doses and intravesical administration schedules of interferon-alpha-2b combined with epirubicin: a pilot study

A total of 62 patients at high risk for recurrence of superficial bladder cancer were selected for a study designed to compare the prophylactic efficacy of different doses and schedules of sequential intravesical instillations of epirubicin and interferon-alpha-2b and to evaluate which sequence could enhance the release of cytokines in the urine. Our investigations showed a significant increase in urinary concentrations of interleukins in patients who received the sequential intravesical administration of epirubicin and interferon-alpha-2b. Higher urinary concentrations of interleukins and a lower recurrence rate were detected in patients who received interferon-alpha-2b 24h after epirubicin instillation.

Gene transfer therapy in cancer

Gene transfer techniques have now achieved clinical realization in the wake of recent advances in recombinant DNA technology, together with increased understanding of the molecular biology and immunology of cancer. These novel treatments, and their applications and limitations merit intensive study.

Ultrastructural evidence of the mechanisms responsible for interleukin-4-activated rejection of a spontaneous murine adenocarcinoma

The ultrastructural pattern of the anti-tumor response elicited by interleukin-4 (IL-4) was investigated by using a spontaneous mammary adenocarcinoma (TS/A) unable to elicit protective immunity in syngeneic BALB/c mice as suggested by a variety of preimmunization-challenge experiments. A subcutaneous lethal challenge of TS/A tumor cells was inhibited in a significant number of BALB/c mice receiving recombinant murine IL-4 injected daily for 10 days around the tumor-draining lymph node. Tumor rejection was mainly the result of direct membrane and cytoplasmic damage to tumor cells by eosinophils, neutrophils and macrophages that deeply penetrated the proliferating tumor mass. Lymphocytes and fibroblasts participated in the reaction by interacting with tumor cells, granulocytes and each other. The most frequent cell interactions in the peri- and intra-tumoral areas and in the tumor-draining lymph nodes are illustrated. The efficiency with which the IL-4-activated reaction leads to tumor inhibition and induction of a T-lymphocyte-dependent tumor-specific immune memory appears to depend on interactions between distinct leukocytes.

IL2 treatment for cancer: from biology to gene therapy

In this review we shall discuss the biological rationale and the clinical findings obtained using Interleukin 2 (IL2)-based immunotherapy in the management of cancer patients. Objective and long-lived clinical responses have been documented in a proportion of cases, particularly renal cell carcinoma, melanoma and acute myeloid leukaemia. Though encouraging, the clinical use of IL2 has so far been limited by toxicity, as well as by the heterogeneous and unpredictable responses and by the lack of specific anti-tumour effect. These considerations have led to the belief that more sophisticated technologies aimed at introducing the IL2 gene into the neoplastic cells may potentially overcome some of the limitations coupled to the in vivo infusion of high doses of IL2. The data accumulated in animal models and, more recently, also with human tumour cells indicate that the IL2 gene may be successfully inserted into neoplastic cells. The constitutive secretion of IL2 by the tumour cells leads to a reduced or abrogated tumorigenicity in several different tumour models. The evidence that in some experimental tumours the transduction of the IL2 gene into the neoplastic cells may elicit a specific cytotoxic response and confer anti-tumour memory, suggests that vaccination protocols based on this innovative strategy may represent a potential new tool in the management of cancer patients.

Human allogeneic melanoma-reactive T-helper lymphocyte clones: functional analysis of lymphocyte-melanoma interactions

Lymphocyte clones were isolated from CD4+ peripheral-blood lymphocytes (PBL) of melanoma (Me) patient 9923 (HLA-DR7, DQw2, w6), co-cultured for 30 days with autologous accessory cells, allogeneic Me (Me 1811) (HLA-DR7, DQw1, w2), IL-1 beta (2 U/ml) and IL-2 (15 IU/ml). The 55 clones tested displayed a CD3+, CD4+, CD8-, T-cell receptor (TCR) alpha/beta+, gamma/delta- phenotype. Twenty clones were assayed for proliferation in the presence of Me 1811 and B-lymphoblastoid cell line (LCL) 1811, both expressing HLA-class-I and -II (DR7 and DQw2 shared with patient 9923), intercellular adhesion molecule-1 (ICAM-1) and lymphocyte-function-associated antigen-3 (LFA-3) molecules. Eight clones were found to be reactive to Me 1811 but not to LCL 1811. Specificity analysis of these 8 clones revealed that each of them proliferated only to Me 1811, not to other 14 Me and 12 different LCL, suggesting recognition of melanoma-associated antigen (MAA) expressed on the stimulating Me. One clone (103) was analyzed in more detail. A wider specificity analysis showed that it reacted to Me 1811 but not to 10 other Me expressing or not HLA-DR7, 5 normal melanocyte cultures (2 of them typing HLA-DR7-positive when exposed to interferon-gamma--IFN-gamma), 4 tumors other than Me and 20 different LCL. Clones did not show proliferation in the presence of autologous Me cells. Clone proliferation in response to Me 1811 was significantly inhibited by monoclonal antibodies (MAbs) directed to CD3, TCR alpha/beta, TCR beta chain V12, CD4 and HLA-DR. Moreover, following stimulation with Me 1811, clone 103 showed increased surface expression of CD25 (IL-2 receptor) and CD71 (transferrin receptor) and produced significant amounts of IL-2 and IFN-gamma. The supernatant taken from co-culture of clone 103 with Me 1811 augmented the cytotoxicity of PBL 9923 and other allogeneic PBL against K562 and Me 1811. Thus, the lymphocyte clone 103 is a CD4+ Th clone which uses its CD3/TCR alpha/beta complex to recognize an MAA in conjunction with HLA-DR7. Availability of this type of reagent may prove useful to identify and characterize MAA recognized by T lymphocytes.

Interleukin-2 injected around tumor-draining lymph nodes in head and neck cancer

Twenty patients with recurrent, inoperable head and neck squamous cell carcinoma received perilymphatic injections of natural interleukin-2 (nIL-2) for 10 days. Ten patients received 200 units (U) of nIL-2; five 1,000 U; and five 5,000 U. Irrespective of the location of the recurrence, the injections were always performed 1.5 cm below the insertion of the sternocleidomastoid muscle on the mastoid. When the ipsilateral lymphatic chain was still present, they were performed on the same side as the tumor site, whereas when it had been stripped as a result of previous surgery, they were contralateral. Patients who had undergone bilateral neck dissection were injected on the tumor side. Whenever possible, the treatment was repeated after 45-day intervals. In 13 patients (65%) with bilateral or contralateral lymph nodes, complete or partial disappearance of the lesion was observed. Despite these marked responses, the tumor always relapsed, and subsequent IL-2 courses were poorly effective. There were no systemic disturbances during or after treatment, but only moderate local swelling and pain.

Attempts to optimize active specific immunotherapy for melanoma

During the past 5 years, we have been conducting clinical trials with a therapeutic melanoma vaccine (melanoma "theraccine"). Mechanical lysates of two melanoma cell lines chosen for their complementary characteristics were combined with the adjuvant DETOX and injected subcutaneously on weeks 1, 2, 3, 4 and 6 for one or two courses, and then monthly in patients with objective clinical responses. Of 109 patients, 22 (20%) have had objective clinical regression of tumor masses, with 5% complete responses. Ten patients have lived more than a year. Eight of the 10 are still alive, five of whom have lived more than 3 years. It was not necessary to achieve complete remissions to cause an increase in survival, and most of the long-surviving patients have one or more (stable) residual nodules. The pace of the disease process has clearly been slowed in those individuals. A rise in the level of cytotoxic T lymphocyte precursors in the blood (pCTL) has correlated with clinical response. Only one patient without such a rise in pCTL has had a response, and assays in that patient were considered unreliable. Both CD4+ and CD8+ CTL have been cloned from the blood of immunized patients. Both types of CTL killed a number of melanoma cell lines, but not other types of tumor or normal cells (lymphoblasts and melanocytes). CD8+ CTL have not been restricted to killing the autologous melanoma. MHC restriction by the HLA-A2 locus was identified. CD4+ CTL were not restricted only by Class II HLA antigens. Many CD4+ clones killed HLA Class II-negative melanomas, and we were able to block cytotoxicity of a particular clone with either anti-HLA Class I or anti-Class II MHC monoclonal antibodies, or both. An association of clinical response to the theraccine with certain HLA phenotypes, notably HLA-C3, -A2 (and the cross-reactive HLA-A28), B12 (and the related alleles (HLA-B44 and -B45) and perhaps DR4, particularly when combinations of those alleles were present, was suggested by our analysis of 70 patients. It is possible that this simply indicates the sharing of MHC antigens between the immunizing melanomas and the patient's melanoma. However, these MHC molecules may be important in their own right in presenting melanoma-associated antigens in CTL in vivo. Subtractive hybridization of mRNA from lung squamous carcinoma cells from cDNA of the M-1 melanoma cell line has yielded several DNA sequences unique to melanoma. Those are now being analyzed for possible immunogenicity, with cytotoxicity by CTL from immunized patients as the major criterion.(ABSTRACT TRUNCATED AT 400 WORDS)

Interleukin 2 gene transfer into tumor cells abrogates tumorigenicity and induces protective immunity

To study the effects of localized secretion of cytokines on tumor progression, the gene for human interleukin 2 (IL-2) was introduced via retroviral vectors into CMS-5 cells, a weakly immunogenic mouse fibrosarcoma cell line of BALB/c origin. Secretion of low levels of IL-2 from the tumor cells abrogated their tumorigenicity and induced a long-lasting protective immune response against a challenge with a tumorigenic dose of parental CMS-5 cells. Co-injection of IL-2-producing CMS-5 cells with unmodified tumor cells inhibited tumor formation even when highly tumorigenic doses of CMS-5 cells were used. Cytolytic activity in mice injected with parental CMS-5 cells was transient and was greatly diminished 3 wk after injection, as commonly observed in tumor-bearing animals. However, in mice injected with IL-2-producing cells, tumor-specific cytolytic activity persisted at high levels for the duration of the observation period (at least 75 d). High levels of tumor-specific cytolytic activity could also be detected in parental CMS-5 tumor-bearing animals 18 d after inoculation with tumor cells, if IL-2-producing CMS-5 cells but not unmodified parental tumor cells were used as targets. These studies highlight the potential advantages of localized secretion of cytokines mediated via gene transfer to induce potent anti-tumor immune responses.

Problems in the investigational study and clinical use of cancer immunotherapy

The last decade has witnessed a veritable explosion in the investigational study and clinical use of immunotherapy for the treatment of cancer. Although this is an exciting development, the promise of cancer immunotherapy has not yet been fulfilled. Why is there an apparent discrepancy between the theory of cancer immunotherapy and the actual results from clinical studies? Michael Osband and Susan Ross suggest that there are several basic problems with the clinical study and therapeutic use of immunotherapy that must be overcome before it can be considered a viable treatment for a broad range of tumors. The purpose of this article is to describe some of the more important of these problems.

Lymphokine-activated tumor inhibition: combinatory activity of a synthetic nonapeptide from interleukin-1, interleukin-2, interleukin-4, and interferon-gamma injected around tumor-draining lymph nodes

This report initially reviews the progressive steps of research designed to build up a new, well-defined helper system triggering both the non-specific and the tumor-specific immune reactivity of a host bearing a tumor, in order to impair tumor growth. Tumor-specific T-helper lymphocytes were first generated in vitro from the spleen of mice with evident tumors. As these lymphocytes inhibit tumor growth by recruiting host reactivity through the release of lymphokines, the peri-tumoral injection of interleukin-2 (IL-2) was then experimented. Repeated injections of 10 units of IL-2 are only weakly effective, but its triggering of an efficient anti-tumor reactivity is markedly enhanced when non-reactive lymphocytes directly obtained from tumor-bearing mice are artificially admixed with the challenge tumor cells. Lastly, in order to ascertain whether lymphocytes themselves could be dispensed with, lymphokines were injected around tumor-draining lymph nodes. Ten daily injections of 1 pg of the 163-171 synthetic nonapeptide of human IL-1 beta appeared very efficient in activating tumor inhibition, particularly when combined with IL-4 or (to a lesser extent) IL-2.