Expression of cytokine mRNA in human melanoma tissues

Portrait of an autologous cancer vaccine: Then and now

Active immunotherapy of cancer with therapeutic vaccines has been the subject of experimental and clinical studies for at least 50 years. Our approach has employed 1) autologous, human cancer cells because of extensive evidence that tumor rejection antigens may differ between multiple tumors of the same histology; 2) the immunopotentiating drug, cyclophosphamide; and 3) haptens, particularly dinitrophenyl. Multiple clinical trials in 455 patients with melanoma and ovarian cancer have shown that administration of haptenized vaccines at the proper dosage-schedule regularly induces T cell-mediated immunity to autologous tumor cells as measured by delayed-type hypersensitivity. Moreover, the vaccine causes changes in the tumor site suggestive of an immune reaction, including inflammation and infiltration with CD8+ T lymphocytes that are activated and produce cytokines. The T cell response is oligoclonal, and dominant Vβ families differ between patients. Studies of measurable metastases show clinically important tumor regression. Commercial development of this technology is clearly feasible.

Advances in COVID-19 mRNA vaccine development

To date, the coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has determined 399,600,607 cases and 5,757,562 deaths worldwide. COVID-19 is a serious threat to human health globally. The World Health Organization (WHO) has declared COVID-19 pandemic a major public health emergency. Vaccination is the most effective and economical intervention for controlling the spread of epidemics, and consequently saving lives and protecting the health of the population. Various techniques have been employed in the development of COVID-19 vaccines. Among these, the COVID-19 messenger RNA (mRNA) vaccine has been drawing increasing attention owing to its great application prospects and advantages, which include short development cycle, easy industrialization, simple production process, flexibility to respond to new variants, and the capacity to induce better immune response. This review summarizes current knowledge on the structural characteristics, antigen design strategies, delivery systems, industrialization potential, quality control, latest clinical trials and real-world data of COVID-19 mRNA vaccines as well as mRNA technology. Current challenges and future directions in the development of preventive mRNA vaccines for major infectious diseases are also discussed.

Recombinant Poxvirus and the Tumor Microenvironment: Oncolysis, Immune Regulation and Immunization

Oncolytic viruses (OVs) are being extensively studied for their potential roles in the development of cancer therapy regimens. In addition to their direct lytic effects, OVs can initiate and drive systemic antitumor immunity indirectly via release of tumor antigen, as well as by encoding and delivering immunostimulatory molecules. This combination makes them an effective platform for the development of immunotherapeutic strategies beyond their primary lytic function. Engineering the viruses to also express tumor-associated antigens (TAAs) allows them to simultaneously serve as therapeutic vaccines, targeting and amplifying an immune response to TAAs. Our group and others have shown that vaccinating intratumorally with a poxvirus that encodes TAAs, in addition to immune stimulatory molecules, can modulate the tumor microenvironment, overcome immune inhibitory pathways, and drive both local and systemic tumor specific immune responses.

Immunomodulatory Factors Control the Fate of Melanoma Tumor Initiating Cells

Melanoma is a highly heterogeneous tumor for which recent evidence supports a model of dynamic stemness. Melanoma cells might temporally acquire tumor-initiating properties or switch from a status of tumor-initiating cells (TICs) to a more differentiated one depending on the tumor context. However, factors driving these functional changes are still unknown. We focused on the role of cyto/chemokines in shaping TICs isolated directly from tumor specimens of two melanoma patients, namely Me14346S and Me15888S. We analyzed the secretion profile of TICs and of their corresponding melanoma differentiated cells and we tested the ability of cyto/chemokines to influence TIC self-renewal and differentiation. We found that TICs, grown in vitro as melanospheres, had a complex secretory profile as compared to their differentiated counterparts. Some factors, such as CCL-2 and IL-8, also produced by adherent melanoma cells and melanocytes did not influence TIC properties. Conversely, IL-6, released by differentiated cells, reduced TIC self-renewal and induced TIC differentiation while IL-10, produced by Me15888S, strongly promoted TIC self-renewal through paracrine/autocrine actions. Complete neutralization of IL-10 activity by gene silencing and antibody-mediated blocking of the IL-10Rα was required to sensitize Me15888S to IL-6-induced differentiation. For the first time these results show that functional heterogeneity of melanoma could be directly influenced by inflammatory and suppressive soluble factors, with IL-6 favoring TIC differentiation, and IL-10 supporting TIC self-renewal. Thus, understanding the tumor microenvironment (TME) role in modulating melanoma TIC phenotype is fundamental to identifying novel therapeutic targets to achieve long-lasting regression of metastatic melanoma. Stem Cells 2016;34:2449-2460.

Collective action of hematopoietic cell subsets mediates anti-IL10R1 and CpG tumor immunity

Based on the specificity of antigen recognition and the ability to generate long-lived memory responses, cancer immunotherapies primarily target tumor-associated T cells. Systemic administration of anti-IL-10R1 antibody in combination with local CpG administration has been shown to induce tumor regression in a T-cell-dependent manner. Here, we confirmed the anti-tumor efficacy of anti-IL-10R1 and CpG therapy in the highly aggressive B16F10 melanoma model. However, T cells were not required for tumor growth inhibition. Through cellular depletions and genetic models of leukocyte deficiency, we demonstrated that T, B, and NK cells, and neutrophils are not essential for anti-tumor efficacy. Nevertheless, hematopoietic cells as a whole are required for anti-IL-10R1- and CpG-induced tumor growth inhibition, suggesting that the collective action of multiple subsets of hematopoietic-derived cells is required for anti-tumor efficacy.

Bladder Cancer Immunotherapy: BCG and Beyond

Mycobacterium bovis bacillus Calmette-Guérin (BCG) has become the predominant conservative treatment for nonmuscle invasive bladder cancer. Its mechanism of action continues to be defined but has been shown to involve a T helper type 1 (Th1) immunomodulatory response. While BCG treatment is the current standard of care, a significant proportion of patients fails or do not tolerate treatment. Therefore, many efforts have been made to identify other intravesical and immunomodulating therapeutics to use alone or in conjunction with BCG. This paper reviews the progress of basic science and clinical experience with several immunotherapeutic agents including IFN-α, IL-2, IL-12, and IL-10.

Interleukin 6 mediates production of interleukin 10 in metastatic melanoma

We previously reported that substantial amounts of IL-10, an immunomodulatory cytokine, are produced by cell suspensions of fresh human metastatic melanoma tissues. Production diminished with continuous culturing of cells, which suggests a pivotal interactive role between melanoma cells and the tumor microenvironment. In this study, we found that the culture media obtained from LPS-stimulated peripheral blood mononuclear cells induced IL-10 production by metastatic melanoma cells. Of the multiple cytokines present in the conditioned culture media, IL-6 was identified as the inducer of IL-10 production. A neutralizing antibody against IL-6 completely blocked the conditioned medium-induced IL-10 production. Metastatic melanoma cells that constitutively produce low amount of IL-10 increased IL-10 production in response to recombinant human IL-6 in a dose-dependent fashion. The response to exogenously added IL-6 was less significant in melanoma cells that produced high amounts of IL-6, probably due to pre-existing autocrine stimulation of IL-10 by endogenous IL-6. On the other hand, metastatic melanoma cells that do not constitutively produce IL-10 protein did not respond to exogenous IL-6. In IL-6-responsive melanoma cells, IL-6 increased STAT3 phosphorylation and inhibition of STAT3 signaling using siRNA or inhibitors for JAKs diminished IL-6-induced IL-10 production. In addition, inhibition of MEK and PI3K, but not mTOR, interfered with IL-10 production. Taken together, the data suggest that blocking of these signals leading to IL-10 production is a potential strategy to enhance an anti-melanoma immune response in metastatic melanoma.

Immunological responses in cancer patients after vaccination with the therapeutic telomerase-specific vaccine Vx-001

Vx-001, an HLA-A*0201 restricted telomerase (TERT)-specific anti-tumor vaccine, is composed of the 9-mer cryptic TERT(572) peptide and its optimized variant TERT(572Y). We have previously shown that Vx-001 is non-toxic, highly immunogenic and in vaccinated NSCLC patients early specific immune response is associated with prolonged survival. The aim of the present study was to investigate the specific T-cell immune response against Vx-001. Fifty-five patients with chemo-resistant advanced solid tumors were vaccinated with TERT(572Y) (2 subcutaneous injections) followed by TERT(572) peptide (4 subcutaneous injections) every 3 weeks. Specific immune response was evaluated by IFN-γ and perforin ELISpot and intracellular cytokine staining assays. TERT-reactive T cells were detected in 27 (51%) out of 53 evaluable patients after the 2nd vaccination and in 22 (69%) out of 32 evaluable patients after the completion of 6 vaccinations. Immune responses developed irrespective of the stage of disease and disease status before vaccination. Patients with disease progression at study entry who developed a post-vaccination-induced immunological response had a significant overall survival benefit compared to the post-vaccination non-responders. The Vx-001 vaccine is a promising candidate for cancer immunotherapy since it can induce a TERT-specific T-cell immune response that is associated with prolonged survival.

Molecular analysis of melanoma-induced sentinel lymph node immune dysfunction

INTRODUCTION

Sentinel lymph nodes (SLNs) of melanoma patients show evidence of tumor-induced immune dysfunction. Our previous works have shown that IL-10 and IFNγ co-regulate indoleamine-2,3-dioxygenase (IDO)-expressing immunosuppressive dendritic cells (DCs) in melanoma SLNs. The goal of this study is to examine the relationship between melanoma SLN tumor burden and the degree of SLN immune dysfunction as a model to study tumor-induced immune dysfunction. We hypothesize that SLN tumor burden correlates with the degree of SLN immune dysfunction.

METHODS

Patients undergoing SLN biopsy for clinical stages I and II melanomas were enrolled in the study under an IRB-approved protocol. During the SLN biopsy, non-hot and non-blue portion of the SLN was harvested, flash-frozen in liquid nitrogen, and mRNA was extracted. By using quantitative real-time PCR, gene expressions of cytokines (IL-4, IL-10, IFNγ, TGFβ, GM-CSF) and the surrogates of immunosuppressive regulatory and effector cells (IDO-expressing DCs and Foxp3-expressing T-regs, respectively) were measured and correlated against the SLN tumor burden (MART1) and against each other. The data were log transformed for normalization. Statistical test used Student's t-test and stepwise multivariate regression analysis. Statistical significance was determined at P < 0.05.

RESULTS

SLNs of 74 patients were analyzed in this analysis. Ten of seventy-four patients (13.5%) had tumor-positive SLNs. MART1 gene expression showed a significant difference between the SLN (+) and SLN (-) groups (P = 0.04). Among the various cytokines, multivariate analysis showed that only IFNγ gene expression correlated independently with MART1 gene expression (P < 0.0001, r = 0.91). Similar multivariate analyses show that IFNγ (P < 0.0001, r = 0.78), IL-10 (P = 0.0037, r = 0.60), and TGFβ (P < 0.0001, r = 0.95) gene expressions correlated independently with IDO gene expression. IFNγ (P < 0.0001, r = 0.87) and GM-CSF (P = 0.042, r = 0.76) gene expressions correlated independently with Foxp3 gene expression. MART1 gene expression showed independent correlation with IDO (P = 0.0002, r = 0.75) and Foxp3 (P = 0.0002, r = 0.75) gene expressions.

CONCLUSION

SLN tumor burden correlates with immunosuppressive IDO and Foxp3 expressions within the SLNs of melanoma patients. Our data are consistent with our theory that melanoma induces expressions of specific cytokines, which in turn, stimulate immune suppressors within the SLN. This study also supports our previous finding that IL-10 and IFNγ co-regulate IDO within the SLN. In our data, IFNγ is the sole cytokine that correlates with the SLN tumor burden and seems to play a central role in tumor-induced immunological changes in the SLN immune microenvironment.

Protocols for the in situ PCR-amplification and detection of mRNA and DNA sequences

In this protocol we describe the in situ PCR method for the amplification of both DNA and mRNA targets [in situ reverse transcriptase-PCR (RT-PCR)], from frozen or paraffin-fixed tissue sections, cell culture or other single-cell suspensions. Detection of amplicons can be achieved by the hybridization and detection of labeled probes. The protocol includes the following steps: (i) tissue preparation, (ii) in situ PCR (or in situ RT-PCR), (iii) probe hybridization, (iv) signal detection. The technique has high sensitivity (geometrically PCR-amplifying 150-350 bp fragments of a gene of interest in situ) and specificity (derived from in situ hybridization with specific fluorescent or biotinylated probes for the target genes). The ability to identify individual cells, expressing or carrying specific genes of interest in a latent form in a tissue section under the microscope provides a visual account of silent genes, and allows the determination of various aspects of normal versus pathological conditions, or latent versus active viral replication. An average of 48 h is required to carry out the technique.

The influence of different culture microenvironments on the generation of dendritic cells from non-small-cell lung cancer patients

INTRODUCTION

Monocyte-derived dendritic cells (DCs) are currently under extensive evaluation as cell vaccines for cancer treatment. Many protocols regarding DCs generation in vitro with different protein components, especially autologous proteins, have been described. On the other hand, active tumor-derived factors in patients' serum could impair monocytes, which might result in their abrogated differentiation into DCs in vitro.

MATERIALS AND METHODS

Autologous DCs from non-small-cell lung cancer (NSCLC)-bearing patients were generated in different culture microenvironments. Peripheral blood mononuclear cells (PBMCs) were cultured in the presence of interleukin-4 and granulocyte-monocyte-stimulating factor with supplementation of 10% autologous serum, 10% allogenic serum, or 2% human albumin. The course of apoptosis, phagocytic ability, and the immunophenotype of the generated DCs were analyzed using flow cytometric methods.

RESULTS

After 48 h of culture, we found a lower percentage of CD1a+/CD14+ and a higher percentage of CD1a+/CD14(-) cells in the culture supplemented with human albumin than in the cultures supplemented with serums. The lowest CD14 antigen expression was found in the human albumin-supplemented 48-h cultures. After 48 h in the cultures carried out with human albumin we found significantly higher percentages of AV+/PI+ cells and AV(-)/PI+ cells than in cultures supplemented with autologous or allogenic serum. We also noted that the expression of FITC-dextran after 4 and 24 h of incubation was significantly higher in the cultures supplemented with both serums than in the HA-SC. The percentage of semi-mature DCs and of CD83 expression was lowest in the culture supplemented with 2% human albumin.

CONCLUSIONS

The kind of culture supplementation had a great impact on the apoptosis of cultured PBMCs. It could also influence the yield of monocyte-derived DCs. It was also confirmed that autologous and allogenic serums provide suitable microenvironments for the generation of autologous DCs from NSCLC patients. The choice of culture supplementation for DC generation is still unsolved and further studies should be undertaken.

M-Vax: an autologous, hapten-modified vaccine for human cancer

The author has devised a novel approach to the immunotherapy of cancer based on modification of autologous tumor cells with the hapten, dinitrophenyl (DNP). This technology is being developed by AVAX Technologies (MO, USA) as a treatment for melanoma under the brand name, M-Vax. The treatment program consists of multiple intradermal injections of DNP-modified autologous tumor cells mixed with bacille Calmette-Guerin as an immunological adjuvant. Administration of DNP vaccine to patients with metastatic melanoma induces a unique reaction--the development of inflammation in metastatic masses. Following DNP-vaccine treatment, almost all patients develop delayed-type hypersensitivity (DTH) to autologous, DNP-modified melanoma cells and about half also exhibit DTH to autologous, unmodified tumor cells. The toxicity of the vaccine is mild, consisting mainly of papules or pustules at the injection sites. Clinical trials have been conducted in two populations of melanoma patients: Stage IV with measurable metastases, and clinical Stage III patients rendered tumor-free by lymphadenectomy. There were 11 antitumor responses in 83 patients with measurable metastases: two complete, four partial and five mixed. In 214 Stage III patients the 5-year overall survival rate was 44%, which compares favorably with the reported surgical rate of 20-25%. In both populations, the induction of DTH to unmodified autologous tumor cells was associated with significantly longer survival. This is a platform technology that is adaptable to other human cancers and early trials indicate immunological activity in ovarian and renal cell carcinomas.

Failure of vaccination with idiotypic protein or DNA, (+/-IL-2), the depletion of regulatory T cells, or the blockade of CTLA-4 to prolong dormancy in mice with BCL1 lymphoma

Immunization of mice with the idiotype (Id) immunoglobulin from the murine B cell lymphoma, BCL1, before inoculating tumor cells can induce tumor dormancy. In this model, the tumor cells grow for a short period of time and then regress. The mice live for months or years with approximately 1 million tumor cells in their spleens. Some mice relapse due to decreases in the anti-Id antibody titers or the development of mutations in the residual tumor cells which render them refractory to negative signaling by the anti-Id antibody. In this study we determined whether we could eliminate the residual dormant cells by using a DNA vaccine against the Id or by immunomodulation of T-cell subsets in vivo. Our results demonstrate that dormancy can be maintained by further immunizations with either the BCL1 Id protein or DNA vaccine encoding its single-chain Fv fragment. We also found that a cytotoxic T-cell response was not induced by either in vivo administration of vaccine alone or by the vaccine plus interleukin-2. In addition the injection of anti-cytotoxic T-lymphocyte-associate antigen did not prolong dormancy. Finally, the in vivo administration of anti-CD25 to deplete regulatory T cells did not prolong dormancy. Dormancy in this model is dependent primarily upon anti-Id antibodies, our results suggest that other strategies to target residual dormant BCL1 cells are warranted. They also suggest that the elimination of dormant tumor may represent a greater challenge than the elimination of primary tumors.

Importance of signaling via the IFN-alpha/beta receptor on host cells for the realization of the therapeutic benefits of cyclophosphamide for mice bearing a large MOPC-315 tumor

Here we show that low-dose cyclophosphamide (CY), that depends for its therapeutic effectiveness on the immunopotentiating activity of the drug for T cell-mediated tumor-eradicating immunity, is curative for approximately 80% of wild-type (WT) mice bearing a large s.c. MOPC-315 tumor, but only for approximately 10% of IFN-alpha/betaR-/- mice bearing a large s.c. MOPC-315 tumor. Histopathological examination of the s.c. tumors of such mice on day 4 after the chemotherapy revealed that the low dose of CY led to accumulation of T lymphocytes in both the WT and the IFN-alpha/betaR-/- mice. However, in the CY treated tumor bearing WT mice the T lymphocytes were present throughout the tumor mass and in direct contact with tumor cells, but in the CY treated tumor bearing IFN-alpha/betaR-/- mice most of the T lymphocytes remained in blood vessels. In addition to being important for CY-induced transendothelial migration of T lymphocytes into the tumor mass, we show here that signaling via the IFN-alpha/betaR is also important for CY-induced control of metastatic tumor progression in the spleen and liver of the tumor bearing mice. Finally, CY cured tumor bearing WT mice were resistant to a subsequent challenge with MOPC-315 tumor cells, but the few CY cured tumor bearing IFN-alpha/betaR-/- mice were not. Thus, signaling via the IFN-alpha/betaR on host cells in MOPC-315 tumor bearers is important for CY-induced: (a) transendothelial migration of T lymphocytes into the tumor mass and the eradication of the primary tumor, (b) control of metastatic tumor progression, and (c) resistance to a subsequent tumor challenge.

The cancer stem cell: evidence for its origin as an injured autoreactive T cell

This review explores similarities between lymphocytes and cancer cells, and proposes a new model for the genesis of human cancer. We suggest that the development of cancer requires infection(s) during which antigenic determinants from pathogens mimicking self-antigens are co-presented to the immune system, leading to breaking T cell tolerance. Some level of autoimmunity is normal and necessary for effective pathogen eradication. However, autoreactive T cells must be eliminated by apoptosis when the immune response is terminated. Apoptosis can be deficient in the event of a weakened immune system, the causes of which are multifactorial. Some autoreactive T cells suffer genomic damage in this process, but manage to survive. The resulting cancer stem cell still retains some functions of an inflammatory T cell, so it seeks out sites of inflammation inside the body. Due to its defective constitutive production of inflammatory cytokines and other growth factors, a stroma is built at the site of inflammation similar to the temporary stroma built during wound healing. The cancer cells grow inside this stroma, forming a tumor that provides their vascular supply and protects them from cellular immune response.

As cancer stem cells have plasticity comparable to normal stem cells, interactions with surrounding normal tissues cause them to give rise to all the various types of cancers, resembling differentiated tissue types. Metastases form at an advanced stage of the disease, with the proliferation of sites of inflammation inside the body following a similar mechanism. Immunosuppressive cancer therapies inadvertently re-invigorate pathogenic microorganisms and parasitic infections common to cancer, leading to a vicious circle of infection, autoimmunity and malignancy that ultimately dooms cancer patients. Based on this new understanding, we recommend a systemic approach to the development of cancer therapies that supports rather than antagonizes the immune system.

Induction of 4-1BB (CD137) expression by DNA damaging agents in human T lymphocytes

4-1BB(CD137) is a member of the tumour necrosis factor receptor superfamily and is expressed on activated T cells, monocytes and natural killer (NK) cells. The interaction of 4-1BB and 4-1BB ligand provides a costimulatory signal leading to T-cell activation. The expression of 4-1BB has been known to be activation dependent. Interestingly, we found that expression of 4-1BB increased in human peripheral blood mononuclear cells after exposure to mitomycin C. Thus, we tested whether the treatment with other DNA-damaging agents, such as doxorubicin, bleomycin, and gamma-irradiation, could induce 4-1BB expression. The data indicated that 4-1BB expression increased dose-dependently by these agents reaching maximum at 2-3 days after the exposure. We found that the major 4-1BB-expressing population was CD3+ T cells, although a moderate number of CD14+ cells and a few NKB1+ cells also expressed 4-1BB. The levels of 4-1BB expression induced by anticancer drugs, were relatively lower than that induced by CD3 ligation. Interestingly, at subcytotoxic concentrations, doxorubicin and bleomycin considerably enhanced 4-1BB expression induced by CD3 ligation in CEM cells. The ligation of the damage-induced 4-1BB by monoclonal antibody enhanced the viability and proliferating capacity of the cells. In conclusion, the expression of 4-1BB might be one of the cellular responses of the immune cells against various genotoxic stresses.

TCR rearrangement in lymphocytes infiltrating melanoma metastases after administration of autologous dinitrophenyl-modified vaccine

Administration of a vaccine consisting of autologous melanoma cells modified with a hapten, dinitrophenyl (DNP), induces T cell infiltration of metastatic sites. We have reported an analysis of these infiltrating T cells, indicating that certain TCR-Vbeta gene segments are greatly overexpressed. In this study, we investigate the rearrangement of the TCR-Vbeta as well as the junctional diversity in T cells infiltrating melanoma metastases following treatment with DNP vaccine. In 19 of 26 control specimens, V-D-J length analysis showed the expected polyclonal patterns. In contrast, postvaccine tumors from 9 of 10 patients showed dominant peaks of V-D-J junction size in one or more Vbeta families. Dominant peaks were seen most frequently in six Vbeta families (Vbeta7, 12, 13, 14, 16, and 23) and were never seen in seven others. Further analysis of the oligoclonal Vbeta products showed dominant peaks in the J region as well. Of particular interest was the finding that Vbeta and Jbeta peaks were similar in inflamed metastases obtained at different times or from different sites from the same patient. Although 6 of 10 patients expressed HLA-A1, there was no common pattern of TCR rearrangements among them. Finally, the amplified PCR products from seven of these specimens were cloned and sequenced and the amino acid sequence of the complementarity-determining region 3 was deduced. In six of seven specimens, the same complementarity-determining region 3 sequence was repeated in at least two clones and in five of seven in at least three clones. Our study indicates that DNP vaccine induces the expansion of particular T cell clones that may be agents of its antitumor effects.

Presence of the human leukocyte antigen class II gene DRB1*1101 predicts interferon gamma levels and disease recurrence in melanoma patients

BACKGROUND

Increased interferon gamma (IFN-gamma) levels are an independent predictor of melanoma recurrence. Human leukocyte antigen (HLA) class II genes can regulate cytokine production; we investigated whether these genes would predict IFN-gamma levels and recurrence in melanoma patients.

METHODS

Of 591 patients who presented with localized melanoma, 579 underwent identification of HLA class II alleles; 233 melanoma patients and 90 controls underwent determination of plasma IFN-gamma levels. HLA class II genes were examined for association with IFN-gamma levels and disease recurrence.

RESULTS

After a median follow-up of 60 months, melanoma patients with IFN-gamma levels above the mean control value were more likely to have developed disease recurrence compared with patients with levels below the mean. The HLA class II gene HLA-DRB1*1101 was the strongest predictor of recurrence, and HLA-DRB1*1101-positive melanoma patients had increased levels of IFN-gamma compared with patients lacking the gene.

CONCLUSIONS

Among patients with localized melanoma, both HLA-DRB1*1101 and increased IFN-gamma levels were associated with an increased risk for recurrence; HLA-DRB1*1101-positive patients had relatively increased levels of IFN-gamma. HLA class II genes may mediate cytokine production in melanoma patients, and this mechanism may help determine the risk of disease recurrence.

M-Vax: an autologous, hapten-modified vaccine for human cancer

A novel approach to active immunotherapy has been devised based on modification of autologous cancer cells with the hapten, dinitrophenyl (DNP). This technology is being developed by AVAX Technologies as a treatment for melanoma under the brand name, M-Vax(TM). The treatment program consists of multiple intradermal injections of DNP-modified autologous tumour cells mixed with Bacille Calmette-Guérin (BCG). DNP-vaccine administration to patients with metastatic melanoma induces a unique reaction - the development of inflammation in metastatic masses. The inflammation is mediated by IFN-gamma-producing T-lymphocytes, some of which represent expansion of novel clones. Following DNP-vaccine treatment, almost all patients develop delayed-type hypersensitivity (DTH) to autologous, DNP-modified melanoma cells; approximately half also exhibit DTH to autologous, unmodified tumour cells. The toxicity of the vaccine is mild, consisting mainly of papules or pustules at the injection sites. Clinical trials have been conducted in two populations of melanoma patients: stage IV with measurable metastases and clinical stage III patients, rendered tumour-free by lymphadenectomy. In 83 patients with measurable metastases, there were 11 antitumour responses: two complete responses (CRs), four partial responses (PRs) and five mixed. Both CRs and two of four PRs occurred in patients with lung metastases. In 214 stage III patients the 5-year overall survival rate was 46% (one nodal site = 48%, in-transit metastases = 50%, two nodal sites = 36%). In both populations, the induction of DTH to unmodified autologous tumour cells was associated with significantly longer survival. This technology is applicable to other human cancers and clinical trials have been initiated with ovarian adenocarcinoma. There appear to be no insurmountable impediments to applying this approach to much larger numbers of patients or to developing it as a standard cancer treatment.

Immunocytochemical increased evidence of inducible nitric oxide synthase, tumor necrosis factor-alpha, and adrenocorticotropic hormone in human peritumoral lymph nodes

In the current study, mesenteric and peritumoral lymph nodes surgically removed from patients with colon-rectum cancer were studied. Morphologic and immunocytochemical investigations demonstrated that mesenteric (control) and peritumoral lymph nodes of a same patient showed the same morphologic structure, but a different immunocytochemical pattern. Indeed, an increased immunoreactivity to anti-inducible nitric oxide synthase, anti-tumor necrosis factor-alpha, and anti-adrenocorticotropic hormone antibodies in the lymphatic tissue of peritumoral lymph nodes compared with mesenteric lymph nodes was observed. These findings suggest that in colon-rectum cancer, the pathologic event induces an increased expression of the molecules involved in the processes of inflammation and carcinogenesis that occurs earlier than the appearance of morphologic modifications.

Melphalan-induced expression of IFN-beta in MOPC-315 tumor-bearing mice and its importance for the up-regulation of TNF-alpha expression

We have previously shown that administration of a low-dose of melphalan (L-phenylalanine mustard; L-PAM) to mice bearing a large s.c. MOPC-315 tumor leads to up-regulation of TNF-alpha expression, which is first evident at the mRNA level at 24 h after the chemotherapy. In this study, we show accumulation of IFN-beta mRNA in the spleen and tumor nodule of such mice as early as 1 h after the chemotherapy followed by elevated production of IFN-beta protein. IFN-beta protein in turn was found to be important for the L-PAM-induced up-regulation of TNF-alpha expression, as neutralization of IFN-beta inhibited the L-PAM-induced up-regulation of TNF-alpha mRNA expression in MOPC-315 tumor cells. In addition, L-PAM failed to up-regulate TNF-alpha expression in spleen cells from mice in which signaling by IFN-beta is deficient. Studies into the mechanism through which L-PAM leads to rapid accumulation of IFN-beta mRNA revealed that it requires de novo RNA synthesis, indicating that the regulation is at the transcriptional level. However, it did not require de novo protein synthesis, indicating that activation of pre-existing transcription factors is sufficient for IFN-beta gene expression. The L-PAM-induced accumulation of IFN-beta mRNA was mimicked with H(2)O(2) and was prevented with the antioxidant N-acetyl-L-cysteine, indicating that reactive oxygen species are involved in the transcriptional regulation of L-PAM-induced IFN-beta gene expression. Thus, the IFN-beta gene is an early response gene that is activated in response to L-PAM via a pathway that involves reactive oxygen species, and IFN-beta in turn plays an important role in L-PAM-induced TNF-alpha up-regulation.

Interleukin-10 and interferon-gamma levels within the peritoneal cavity of patients with gastric cancer

BACKGROUND AND OBJECTIVES

Immune status in the peritoneal cavity of patients with gastric cancer remains largely unknown. To clarify the clinical significance of the host immune response within the peritoneal cavity, we examined the levels of interferon-gamma (IFN-gamma), a type 1 cytokine, and interleukin-10 (IL-10), a type 2 cytokine, in peritoneal washings obtained from patients with gastric cancer.

METHODS

Both the concentrations of IFN-gamma and of IL-10 in peritoneal washings obtained during surgery from 56 patients with gastric cancer were determined by an enzyme-linked immunosorbent assay.

RESULTS

The IFN-gamma level was not correlated with the IL-10 level. The IL-10 level increased in a stage-dependent manner. The high IL-10 level correlated with an unfavorable outcome, whereas there was no relationship between the IFN-gamma level and survival rate. However, among the stage III-IV cancer patients, the high IFN-gamma level correlated with a favorable outcome, while there was no relationship between the IL-10 level and survival rate.

CONCLUSION

Although the IL-10 level increases with tumor progression, the outcome of patients with advanced gastric cancer may be affected by the IFN-gamma level, but not by the IL-10 level, in the peritoneal cavity.

Mechanism of melphalan-induced B7-1 gene expression in P815 tumor cells

We have previously shown that exposure of P815 tumor cells to melphalan (L-phenylalanine mustard; L-PAM) leads to up-regulation of B7-1 surface expression, and this L-PAM-induced up-regulation requires de novo RNA synthesis and is associated with accumulation of B7-1 mRNA. Here we show that the effect of L-PAM on B7-1 surface expression can be mimicked by exposing P815 tumor cells to oxidative stress but not to heat shock. Moreover, the antioxidant N-acetyl-L-cysteine prevented the L-PAM-induced accumulation of B7-1 mRNA in P815 tumor cells, suggesting that reactive oxygen species are involved in the transcriptional regulation of L-PAM-induced B7-1 gene expression. Although AP-1 and NF-kappaB are regarded as redox-sensitive transcription factors and the promoter/enhancer region of the B7-1 gene contains an AP-1 and an NF-kappaB binding site, exposure of P815 tumor cells to L-PAM led to rapid and transient activation only of NF-kappaB, but not AP-1, that bound specifically to a probe containing the respective binding site in the murine or human B7-1 gene. Moreover, exposure of P815 tumor cells to a cell-permeable peptide that selectively inhibits NF-kappaB activation by blocking the activation of the IkappaB-kinase complex was found to inhibit the L-PAM-induced B7-1 mRNA accumulation, indicating that NF-kappaB activation is essential for the L-PAM-induced B7-1 gene expression. Taken together, these results indicate that L-PAM leads to activation of B7-1 gene expression by activating NF-kappaB via a pathway that involves reactive oxygen species.

Comparison of serum interleukin-10 (IL-10) levels between normal volunteers and patients with advanced melanoma

Melanoma is an immunoresponsive malignancy. Interleukin-10 (IL-10) is a potent regulator of immunosuppression. The purpose of this research was to define the relationship of serum IL-10 to survival in patients with metastatic melanoma. Forty-one melanoma patients and 50 normal volunteers were analyzed. The median IL-10 level as determined by enzyme-linked immunosorbent assay (ELISA) in melanoma patients was 8.75 pg/ml compared to < 3.0 pg/ml in normal volunteers (p = 0.0001). Survival of melanoma patients with an IL-10 level above 10.0 pg/ml was 365 days compared to 557 days in patients with IL-10 levels less than 10.0 pg/ml (p = 0.0259, Wilcoxon). Elevated IL-10 levels were correlated with poor survival.

Autologous, hapten-modified vaccine as a treatment for human cancers

We have devised a novel approach to active immunotherapy based on modification of autologous cancer cells with the hapten, dinitrophenyl (DNP). The treatment program consists of multiple intradermal injections of DNP-modified autologous tumor cells mixed with BCG. Administration of DNP-vaccine to patients with metastatic melanoma induces a unique reaction - the development of inflammation in metastatic masses. Histologically, this consists of infiltration of T lymphocytes, most of which are CD8+. These T cells usually produce gamma interferon in situ. Moreover, they represent expansion of T cell clones with novel T cell receptor structures. Occasionally, administration of DNP-vaccine results in partial or complete regression of measurable metastases. The most common site of regression has been small lung metastases. Administration of DNP-vaccine to patients in the post-surgical adjuvant setting produces a more striking clinical effect. We have treated 214 patients with clinically evident stage III melanoma who had undergone lymphadenectomy. With a median follow-up time of 4.4 years (1.8-10.4 years) the 5-year overall survival (OS) rate is 47% (one nodal site = 51%, two nodal sites = 33%). These results appear to be comparable to those obtained with high dose interferon. More recent studies suggest that this therapeutic approach is also applicable to ovarian cancer. There appear to be no insurmountable impediments to applying this approach to much larger numbers of patients or to developing it as a standard cancer treatment.

Significance of plasma cytokine levels in melanoma patients with histologically negative sentinel lymph nodes

INTRODUCTION

Although sentinel lymph node (SLN) status is the most powerful predictor of prognosis in patients with clinically localized melanoma, a proportion of melanoma patients with histologically negative SLNs will still recur. It is hypothesized that tumor response may be altered or mediated by specific cytokines. We therefore investigated whether levels of IL-4, IL-6, IL-10, TNF-alpha, or IFN-gamma would predict disease recurrence in melanoma patients with histologically negative SLNs.

METHODS

This prospective cohort study involved 218 patients with clinically localized melanoma who underwent a histologically negative SLN biopsy. Preoperative plasma cytokine levels were determined by enzyme-linked immunosorbent assay on these patients, as well as on 90 healthy controls. Kaplan-Meier life tables were constructed, and Cox proportional hazards analyses were performed to assess predictors of disease-free survival (DFS).

RESULTS

At a median follow-up of 43 months, 33 of 218 patients (15%) had suffered disease recurrence. Melanoma patients had significant elevations of IL-4, IL-6, and IL-10 compared to healthy controls; levels of IFN-gamma were less elevated in melanoma patients compared to controls. Despite this, melanoma patients with detectable IFN-gamma levels were at significantly higher risk for recurrence compared to patients with undetectable levels (5-year DFS 70% vs. 86%, P = .03). On multivariate analysis including standard melanoma prognostic factors, only tumor thickness (P = .004) and the presence of detectable IFN-gamma levels (P = .05) were significant independent prognostic factors for disease-free survival.

CONCLUSIONS

Among melanoma patients with clinically localized disease who have undergone a histologically negative SLN biopsy, presence of a detectable plasma level of IFN-gamma is an independent predictor of disease recurrence. Elevated levels of IFN-gamma may identify a group of early-stage melanoma patients who are more likely to have recurrence of disease and who may benefit from adjuvant therapies, including immunotherapies.

Cellular immune profile of patients with advanced cancer before and after taxane treatment

The purpose of this study is to determine immune recovery and function after treatment with docetaxel or paclitaxel. Peripheral blood mononuclear cells were harvested before chemotherapy and at weekly times afterwards for cycle 1. Leukocyte subsets ICD45hiCD14lo polymorphonuclear neutrophils, CD45hiCD14hi monocytes, CD45hiCD14- lymphocytes, CD3+CD4/CD8+ T cells, CD3-CD19+ B cells, CD3-CD16/CD56+ natural killer (NK) cells], and circulating cytokine levels [tumor necrosis factor-alpha, gamma-interferon (gamma-IFN), and interleukins (IL-2, IL-10, IL-12)] were followed. In addition, T-cell mitogenic function, NK function, and lymphokine activated killer (LAK) function was assessed. Ten patients were entered in the trial. T-cell frequency, B-cell frequency, and CD4/CD8 ratio did not change. IL-10 serum levels significantly decreased in paclitaxel-treated patients (4.4+/-1.3 pg/ml at week 4 versus 7.8+/-2.1 pg/ml at baseline; p < 0.05). IL-2, IL-12, and gamma-IFN levels were not detectable. NK cytotoxic activity decreased in docetaxel-treated patients. LAK cell activity was not altered. Four patients achieved a partial or complete response. They demonstrated higher than normal CD4:CD8 T-cell ratios and an improved phytohemagglutinin stimulation index (SI = 2.5). In conclusion, our findings suggest that immune function was affected more significantly after docetaxel treatment. Investigational approaches, which enhance cellular immunity, may be of greater relevance after treatment with docetaxel. Additional studies monitoring NK function after chemotherapy are recommended.

Melphalan and other anticancer modalities up-regulate B7-1 gene expression in tumor cells

In this study, we show that administration of low-dose melphalan (l -PAM, l -phenylalanine mustard) to mice bearing a large MOPC-315 plasmacytoma led to a rapid up-regulation of B7-1 (CD80), but not B7-2 (CD86), expression on the surface of MOPC-315 tumor cells. This l -PAM-induced preferential up-regulation of B7-1 surface expression was due, at least in part, to a direct effect of l -PAM on the tumor cells, as in vitro exposure of MOPC-315 tumor cells to l -PAM led to the preferential up-regulation of B7-1 surface expression. Moreover, in vitro exposure of MOPC-315 tumor cells to two other anticancer modalities, gamma-irradiation and mitomycin C, resulted in the preferential up-regulation of B7-1 surface expression. This effect was not restricted to MOPC-315 tumor cells, as preferential up-regulation of B7-1 surface expression was observed also following in vitro exposure of the P815 mastocytoma (that is negative for both B7-1 and B7-2 surface expression) to any of the three anticancer modalities. The up-regulation of B7-1 surface expression following in vitro exposure of tumor cells to l -PAM, gamma-irradiation, or mitomycin C required de novo protein and RNA synthesis, and was associated with the accumulation of mRNA for B7-1 within 4-8 h, indicating that the regulation of B7-1 expression is at the RNA transcriptional level. These results have important implications for an additional immune-potentiating mechanism of these anticancer modalities in clinical setting.

Tumor-associated transforming growth factor-beta and interleukin-10 contribute to a systemic Th2 immune phenotype in pancreatic carcinoma patients

In this study, we report coexpression of transforming growth factor-beta (TGF-beta) and interleukin-10 (IL-10) in pancreatic carcinoma tissue associated with significantly elevated levels of both cytokines in the sera of pancreatic carcinoma patients. Using conditioned media (CM) of pancreatic carcinoma cells, we further demonstrate that tumor cell-derived TGF-beta and IL-10 inhibited in an additive fashion both proliferation and the development of Th1-like responses in peripheral blood mononuclear cell (PBMC) preparations derived from normal donors. The antiproliferative and Th1-suppressive activities contained in CM of pancreatic carcinoma cells were due primarily to IL-10 and/or TGF-beta, as shown by the capacity of cytokine-specific neutralizing antibodies to reverse these effects. Finally, as compared to normal controls, PBMC derived from pancreatic carcinoma patients displayed a Th2-like cytokine expression pattern upon activation with either anti-CD3 antibody or Staphylococcus aureus strain Cowan I. Taken together, these results suggest that aberrant production of TGF-beta and IL-10 in pancreatic tumor patients skews T-cell cytokine production patterns in favor of a Th2 immunophenotype.

Interleukin-10–Treated Human Dendritic Cells Induce a Melanoma-Antigen–Specific Anergy in CD8+ T Cells Resulting in a Failure to Lyse Tumor Cells

Dendritic cells (DC) are critically involved in the initiation of primary immune processes, including tumor rejection. In our study, we investigated the effect of interleukin-10 (IL-10)–treated human DC on the properties of CD8+ T cells that are known to be essential for the destruction of tumor cells. We show that IL-10–pretreatment of DC not only reduces their allostimulatory capacity, but also induces a state of alloantigen-specific anergy in both primed and naive (CD45RA+) CD8+ T cells. To investigate the influence of IL-10–treated DC on melanoma-associated antigen-specific T cells, we generated a tyrosinase-specific CD8+ T-cell line by several rounds of stimulation with the specific antigen. After coculture with IL-10–treated DC, restimulation of the T-cell line with untreated, antigen-pulsed DC demonstrated peptide-specific anergy in the tyrosinase-specific T cells. Addition of IL-2 to the anergic T cells reversed the state of both alloantigen- or peptide-specific anergy. In contrast to optimally stimulated CD8+ T cells, anergic tyrosinase-specific CD8+ T cells, after coculture with peptide-pulsed IL-10–treated DC, failed to lyse an HLA-A2–positive and tyrosinase-expressing melanoma cell line. Thus, our data demonstrate that IL-10–treated DC induce an antigen-specific anergy in cytotoxic CD8+ T cells, a process that might be a mechanism of tumors to inhibit immune surveillance by converting DC into tolerogenic antigen-presenting cells.

Interleukin-10–Treated Human Dendritic Cells Induce a Melanoma-Antigen–Specific Anergy in CD8+ T Cells Resulting in a Failure to Lyse Tumor Cells

Dendritic cells (DC) are critically involved in the initiation of primary immune processes, including tumor rejection. In our study, we investigated the effect of interleukin-10 (IL-10)–treated human DC on the properties of CD8+ T cells that are known to be essential for the destruction of tumor cells. We show that IL-10–pretreatment of DC not only reduces their allostimulatory capacity, but also induces a state of alloantigen-specific anergy in both primed and naive (CD45RA+) CD8+ T cells. To investigate the influence of IL-10–treated DC on melanoma-associated antigen-specific T cells, we generated a tyrosinase-specific CD8+ T-cell line by several rounds of stimulation with the specific antigen. After coculture with IL-10–treated DC, restimulation of the T-cell line with untreated, antigen-pulsed DC demonstrated peptide-specific anergy in the tyrosinase-specific T cells. Addition of IL-2 to the anergic T cells reversed the state of both alloantigen- or peptide-specific anergy. In contrast to optimally stimulated CD8+ T cells, anergic tyrosinase-specific CD8+ T cells, after coculture with peptide-pulsed IL-10–treated DC, failed to lyse an HLA-A2–positive and tyrosinase-expressing melanoma cell line. Thus, our data demonstrate that IL-10–treated DC induce an antigen-specific anergy in cytotoxic CD8+ T cells, a process that might be a mechanism of tumors to inhibit immune surveillance by converting DC into tolerogenic antigen-presenting cells.

Phenotyping of immune cell infiltrates in breast and colorectal tumours

White cell infiltration of solid tumors is an important prognostic indicator in malignant disease. Although macrophage infiltration is associated with good outcome in colorectal cancer, a high macrophage content is associated with poor prognosis in breast cancer. Suppressor macrophages prevent T cell activation in normal tissues such as mucosal linings exposed to continuous antigenic challenge. Interleukin 10 (IL-10), an immunosuppressive cytokine, inhibits macrophage co-stimulation of T cells. Suppressor macrophage numbers, T cell numbers and T cell activation status were assessed in cell suspensions obtained from fresh specimens of breast and colorectal tumours and matched normal tissues. IL-10 production by both malignant and matched normal tissue was also assessed. This study identified elevated numbers of suppressor macrophages in breast tumors compared to matched normal breast tissue. Colorectal tumors did not contain significant numbers of these cells. Although T cell numbers are increased in breast tumors, these cells do not appear to be fully activated, as assessed by major histocompatibility complex class II and Interleukin 2 receptor expression. In contrast, T cells in colorectal tumors exhibit greater expression levels of these markers. Breast tumors produce significantly higher levels of IL-10 than normal breast tissue whereas IL-10 levels in colorectal tumors are similar to normal colon tissue. Our findings of high suppressor macrophage numbers, high levels of IL-10 and poorly activated T cells in breast tumors compared to low suppressor macrophage numbers, low IL-10 and fully activated T cells in colorectal tumors may explain why high macrophage content is associated with poor prognosis in breast cancer and good prognosis in colorectal malignancy.

Vaccination with irradiated autologous melanoma cells engineered to secrete human granulocyte-macrophage colony-stimulating factor generates potent antitumor immunity in patients with metastatic melanoma

We conducted a Phase I clinical trial investigating the biologic activity of vaccination with irradiated autologous melanoma cells engineered to secrete human granulocyte-macrophage colony-stimulating factor in patients with metastatic melanoma. Immunization sites were intensely infiltrated with T lymphocytes, dendritic cells, macrophages, and eosinophils in all 21 evaluable patients. Although metastatic lesions resected before vaccination were minimally infiltrated with cells of the immune system in all patients, metastatic lesions resected after vaccination were densely infiltrated with T lymphocytes and plasma cells and showed extensive tumor destruction (at least 80%), fibrosis, and edema in 11 of 16 patients examined. Antimelanoma cytotoxic T cell and antibody responses were associated with tumor destruction. These results demonstrate that vaccination with irradiated autologous melanoma cells engineered to secrete granulocyte-macrophage colony-stimulating factor stimulates potent antitumor immunity in humans with metastatic melanoma.

Constitutive IL-10 Production Accounts for the High NK Sensitivity, Low MHC Class I Expression, and Poor Transporter Associated with Antigen Processing (TAP)-1/2 Function in the Prototype NK Target YAC-1

Tumor cells that are treated with rIL-10 or transfected with the IL-10 gene show phenotypic changes. These include low but peptide-inducible expression of MHC class I, low sensitivity to specific CTL-mediated lysis, and increased NK sensitivity. In vitro-established mouse tumor lines were screened for IL-10 expression and production, and a large proportion of plasmocytomas or T cell lymphomas were found to produce IL-10. Since one of these lines was the prototype NK target cell YAC-1, we investigated whether the high IL-10 production of this cell line was related to its high NK sensitivity and its defects in MHC class I expression. The decrease in H-2 expression following the in vitro culture of in vivo-passaged YAC-1 cells was accompanied by a gradual increase in IL-10 production, whereas the reverse was found when passing in vitro-grown YAC-1 in vivo as an ascites tumor in syngenic mice. In addition, differences in YAC-1 MHC class I expression correlated with alterations in the functional activity of TAP-1/2 proteins. YAC-1 cells that were transduced with a retroviral IL-10 antisense construct (Y-IL-10 AS) only produced about half of the IL-10 that was produced by YAC-1 transduced with the control construct (Y-IL-10 Mock). Relative to Y-IL-10 Mock cells, the expression of H-2 on Y-IL-10 AS cells was markedly increased, and NK sensitivity was decreased. These data argue for a mechanism wherein IL-10 production is causally related to the low H-2 expression, decreased TAP function, and high NK sensitivity of YAC-1 cells.

Neutralizing anti-IL-10 antibody upregulates the induction and elicitation of contact hypersensitivity

Various cytokines have been shown to modulate the acquisition and expression of delayed-type hypersensitivity. In a mouse model, we tested the notion that neutralization of interleukin-10 (IL-10), a cytokine that inhibits T cell-mediated reactions, would upregulate delayed-type hypersensitivity. We used two different monoclonal antibodies with specificity for murine IL-10 and used allergic contact dermatitis as a prototypical example of delayed-type hypersensitivity. When anti-IL-10 antibody was given at the time of sensitization to a contact allergen, there was a substantial increase in the induced contact hypersensitivity (CHS). In other experiments, the challenge reactions to contact allergen in routinely sensitized mice were increased when anti-IL-10 antibody was given at the time of challenge. Primary irritant reactions to croton oil were increased but only if anti-IL-10 antibody was given at the time of challenge and not when it was given a week previously. It appears that anti-IL-10 antibody can potentiate CHS reactivity by inactivating otherwise downregulating endogenous IL-10.

Dinitrophenyl-modified autologous melanoma vaccine induces a T cell response to hapten-modified, melanoma peptides

Active specific immunotherapy with dinitrophenyl (DNP)-modified autologous melanoma vaccine elicits inflammatory responses in metastatic tumor sites. Postsurgical adjuvant immunotherapy with this vaccine prolongs survival in stage III melanoma patients. We have reported that, after administration of DNP-modified melanoma vaccine, T cell responses to DNP-modified autologous tumor cells are demonstrable in vivo and in vitro. These responses are hapten specific and MHC restricted. To elucidate this phenomenon, we investigated the immune response to DNP-modified peptides eluted from autologous cells. Short peptides were extracted from DNP-modified and unmodified autologous melanoma cells by an acid elution technique and HPLC fractionation. Peptides were also extracted from DNP-modified and unmodified, EB virus-transformed, autologous B lymphoblasts. These various peptide fractions were loaded onto autologous B lymphoblasts and tested for ability to elicit a response by a DNP-specific T cell line as measured by IFN-gamma production. Unexpectedly, stimulatory activity of peptides from DNP-modified melanoma cells was confined to a single HPLC fraction. Spectrometric analysis of this fraction confirmed modification of peptides with DNP. A weaker T cell response was observed to a single HPLC fraction of DNP-modified peptides from the patient's B lymphoblasts. No T cell response was elicited by corresponding fractions of peptides eluted from unmodified melanoma cells or B lymphoblasts. These findings demonstrate the human T cell response to DNP-modified autologous melanoma cells is mediated by hapten-modified, MHC-associated peptides. Further investigation of these peptides could lead to a new strategy for peptide-based cancer immunotherapy.

Techniques to investigate cellular and molecular interactions in the host response to implanted biomaterials

Evaluation of the host response to implanted materials requires systematic, objective investigations of responses at both the cellular and molecular levels. This article explains the basis behind two technologies: antibody and molecular techniques, which will give valuable information when applied to investigations of cells and molecules involved in the host biomaterial interaction. Such investigations are well underway, and a number of groups are now studying well characterised cell markers or molecules to evaluate the host response to biomaterials. Here we outline current technologies for the development of antibodies as tools to study cell markers or molecules, including those for which reagents are not yet available and DNA based technologies, whose continued application should prove an invaluable adjunct to existing approaches. These technologies may be particularly valuable to investigations focusing on newly characterised cytokines, receptors or cell adhesion molecules and subsequently provide a way forward for the production of advanced biomaterials.

Potentiation of antitumor CTL response by GM-CSF involves a B7-dependent mechanism

We have previously demonstrated the importance of endogenous GM-CSF production for the B7-2-dependent potentiating effect of exogenous TNF for CTL generation by stimulation cultures of splenic cells from mice bearing a large MOPC-315 tumor. Here we show that addition of GM-CSF to stimulation cultures of such tumor-bearer splenic cells also leads to the generation of enhanced anti-MOPC-315 CTL activity via a B7-dependent mechanism. However, while the potentiating effect of TNF was previously shown to be IL-2-independent, the potentiating effect of GM-CSF is shown here to be completely IL-2-dependent. Still, the potentiating activity of exogenous GM-CSF for the in vitro generation of CTL activity is shown to depend completely on endogenous TNF production. Finally, TNF and GM-CSF may cooperate in enhancing the in vivo generation of CTL activity in MOPC-315 tumor bearers because low-dose melphalan (L-phenylalanine mustard) therapy, which was previously shown to lead to the rapid up-regulation of TNF production at the tumor site and the subsequent TNF-dependent in vivo acquisition of potent CTL activity, is shown here to lead to the rapid up-regulation of GM-CSF production at the tumor site.

Interleukin-10 is a growth factor for human melanoma cells and down-regulates HLA class-I, HLA class-II and ICAM-1 molecules

IL-10 is a cytokine which shows various effects including inhibition of T-cell proliferation or HLA-dependent antigen presentation. In this study, we analysed the effects of exogenous or autocrine IL-10 on proliferation and expression of immunocritical surface molecules. Fourteen cultures of human melanoma cells were established from primary melanomas, locoregional lymph-node or distant metastases. In 5 melanoma cell cultures, proliferation in the presence of IL-10, anti-IL-10 antibodies (Ab) or control Ab was assessed with colorimetric and [3H]thymidine uptake assays. Flow cytometric analysis was used to quantify the expression of human leukocyte antigen (HLA) class-I, HLA class-II and intercellular adhesion molecule (ICAM)-1 and the IL-10 receptor (IL-10R). IL-10 production of melanoma cells was documented by RT-PCR and IL-10 protein was detected in the supernatants by means of ELISA. IL-10 enhanced proliferation and prolonged survival of melanoma cells in 5 out of 5 cultures. Anti-IL-10 Ab decreased proliferation. IL-10R expression was found in 12 out of 14 (86%) melanoma cell cultures. The expression of HLA-I, HLA-II and ICAM-1 on all melanoma cells that were positive for IL-10R showed a reduction of 10-60% by IL-10, whereas the surface levels of HLA-I, HLA-II and ICAM-1 in 5 out of 5 cell cultures revealed an increase of 10-170% by anti-IL-10 Ab. These findings suggest that IL-10 is an autocrine growth factor with significant impact on immunocritical molecules in melanoma. IL-10 effects have to be considered when planning therapeutic immunointerventions in melanoma patients.

Clonal expansion of T lymphocytes in human melanoma metastases after treatment with a hapten-modified autologous tumor vaccine

Metastatic melanoma patients treated with an autologous DNP-modified tumor cell vaccine develop inflammatory responses in metastatic tumors characterized by infiltration of CD8+ T cells. To further define this immune response, we analyzed T cell receptor beta-chain variable (TCRBV) region repertoire in biopsy specimens and peripheral blood lymphocytes of six patients. After administration of DNP vaccine, a restricted set of TCRBV gene families was found to be expanded compared with prevaccine metastases. In several postvaccine lesions of one patient, obtained over a 2-yr period, TCRBV14+ T cells were clonally expanded and identical T cell clonotypes could be detected. Two major recurring clones were biased toward the use of TCRBJ1S5. Furthermore, T cell lines derived from two such infiltrated skin lesions and, enriched in TCRBV14+ T cells, displayed HLA-class I-restricted lysis of the autologous melanoma cells. Clonal expansion of T cells was demonstrated in the T cell-infiltrated, postvaccine metastasis of a second patient as well. These results indicate that vaccination with autologous, DNP-modified melanoma cells can expand selected clones of T cells at the tumor site and that such clones are potentially destructive to the tumor.

Interleukin-10 production in malignant melanoma: preferential detection of IL-10-secreting tumor cells in metastatic lesions

IL-10 mRNA expression and protein production in established melanoma cell lines and freshly cultured primary and metastatic melanoma cells was examined. The in situ distribution of IL-10 in native melanoma tissue was also investigated by immunohistochemistry in primary tumors, metastases, benign melanocytic nevi and normal skin of healthy persons and melanoma patients. IL-10 mRNA, but not IL-10 protein in the culture supernatant, was found in 1 of 4 cultured melanoma cells of primary tumors, while 3 of 6 melanoma-metastasis-derived cultures expressed both IL-10 mRNA and protein. No IL-10 was detected in skin biopsies of healthy volunteers or in the healthy skin of melanoma patients; nor was IL-10 found in congenital melanocytic nevi. In only 1 of the 11 examined primary malignant melanomas was IL-10 immunoreactivity detected within the cytoplasm of cells in the tumor. On the other hand, 4 of 9 metastases clearly displayed scattered IL-1O+ cells. In all sections with IL-10-positive cells, the cells were positive for HMB-45. No co-expression of CD3 and IL-10 was observed. The data suggest that melanoma cells themselves are the main origin of IL-10 in tumor specimens in vivo. The preferential expression of IL-10 in metastatic lesions and in cultured cells from metastases might indicate an increased spreading potential of IL-10-secreting melanoma-cell clones.

Low-dose-melphalan-induced up-regulation of type-1 cytokine expression in the s.c. tumor nodule of MOPC-315 tumor bearers and the role of interferon gamma in the therapeutic outcome

We have previously shown the importance of endogenous tumor necrosis factor (TNF) production for the curative effectiveness of low-dose melphalan (L-phenylalanine mustard) for mice bearing a large MOPC-315 tumor. In the current study we demonstrate that low-dose melphalan is actually associated with enhanced expression of mRNA for TNF alpha in the s.c. tumor nodule. Moreover, the expression of mRNA for interferon gamma (IFN gamma) and interleukin-12 (IL-12; p40) is also elevated at the tumor site. However, while elevation in the expression of mRNA for TNF alpha and IFN gamma is evident within 24 h after the chemotherapy, elevation in the expression of mRNA for IL-12(p40) is first evident 72 h after the chemotherapy. Moreover, neutralizing anti-IFN gamma mAb, like neutralizing anti-TNF mAb but not neutralizing anti-IL-12 mAb, reduced the curative effectiveness of low-dose melphalan for MOPC-315 tumor bearers. Studies into the mechanism through which IFN gamma mediates its antitumor effect in low-dose-melphalan-treated MOPC-315 tumor-bearing mice revealed that MOPC-315 tumor cells, which are not sensitive to the direct antitumor effects of TNF, display some sensitivity to the antiproliferative activity of high concentrations of IFN gamma. However, unlike TNF alpha, IFN gamma is unable to promote the generation of anti-MOPC-315 cytotoxic T lymphocyte activity and, in fact, exerts an inhibitory activity on CTL generation. Taken together, our studies illustrate that low-dose melphalan therapy of MOPC-315 tumor bearers is associated with the rapid elevation in the expression of mRNA for IFN gamma and TNF, two cytokines which are important for the curative effectiveness of low-dose melphalan, and which mediate their antitumor effect, in part, through distinct mechanisms.