ICAM- melanoma cells are relatively resistant to CD3-mediated T-cell lysis

How patients with an intact immune system develop head and neck cancer

Although the adaptive immune system can detect and eliminate malignant cells, patients with intact and fully functional immune systems develop head and neck cancer. How is this paradox explained? Manuscripts published in the English language from 1975 to 2018 were reviewed using search inputs related to tumor cell antigenicity and immunogenicity, immunodominance, cancer immunoediting and genomic alterations present within carcinomas. Early in tumor development, T cell responses to immunodominant antigens may lead to the elimination of cancer cells expressing these antigens and a tumor composed to tumor cells expressing only immunorecessive antigens. Conversely, other tumor cells may acquire genomic or epigenetic alterations that result in an antigen processing or presentation defect or other inability to be detected or killed by T cells. Such T cell insensitive tumor cells may also be selected for in a progressing tumor. Tumors harboring subpopulations of cells that cannot be eliminated by T cells may require non-T cell-based treatments, such as NK cell immunotherapies. Recognition of such tumor cell populations within a heterogeneous cancer may inform the selection of treatment for HNSCC in the future.

Distinct patterns of cytolytic T-cell activation by different tumour cells revealed by Ca2+ signalling and granule mobilization

Cancer-germline genes in both humans and mice have been shown to encode antigens susceptible to targeting by cytotoxic CD8 T effector cells (CTL). We analysed the ability of CTL to kill different tumour cell lines expressing the same cancer-germline gene P1A (Trap1a). We previously demonstrated that CTL expressing a T-cell receptor specific for the P1A_35-43 peptide associated with H-2L^d , although able to induce regression of P1A-expressing P815 mastocytoma cells, were much less effective against P1A-expressing melanoma cells. Here, we analysed parameters of the in vitro interaction between P1A-specific CTL and mastocytoma or melanoma cells expressing similar levels of the P1A gene and of surface H-2L^d . The mastocytoma cells were more sensitive to cytolysis than the melanoma cells in vitro. Analysis by video-microscopy of early events required for target cell killing showed that similar patterns of increase in cytoplasmic Ca²⁺ concentration ([Ca²⁺ ]i) were induced by both types of P1A-expressing tumour cells. However, the use of CTL expressing a fluorescent granzyme B (GZMB-Tom) showed a delay in the migration of cytotoxic granules to the tumour interaction site, as well as a partially deficient GZMB-Tom exocytosis in response to the melanoma cells. Among surface molecules possibly affecting tumour-CTL interactions, the mastocytoma cells were found to express intercellular adhesion molecule-1, the ligand for LFA-1, which was not detected on the melanoma cells.

Circulating soluble intercellular adhesion molecule-1 in lung cancer: a systematic review

Soluble intercellular adhesion molecule-1(sICAM-1) has been implicated in tumor progression and metastasis. However the expression of circulating sICAM-1 as well as its diagnostic and prognostic value in patients with lung cancer remains controversial. We performed an electronic database (including PubMed, Web of Science, and Medline) search with the terms "ICAM", "intercellular adhesion molecule" and "lung cancer", and summarized the results of eligible studies in order to review the expression of sICAM-1 as well as its clinical significance in lung cancer. According to our literature search, we conducted a final analysis of 1258 patients from 16 studies. And we revealed that the circulating concentration of sICAM-1 in lung cancer patients was significantly higher than that in healthy controls. Additionally, baseline sICAM-1 levels apparently were associated with ECOG performance status, gender, histology type and disease stages. Furthermore, there seems to be a significantly inverse association between sICAM-1 levels, prognosis and response rate in NSCLC patients. In conclusion, sICAM-1 appeared to be a potential diagnostic and prognostic biomarker in lung cancer patients. Additional prospective studies are required to confirm this issue.

A syngeneic orthotopic murine model of pancreatic adenocarcinoma in the C57/BL6 mouse using the Panc02 and 6606PDA cell lines

BACKGROUND/AIMS

To develop a clinically relevant immunocompetent murine model to study pancreatic cancer using two different syngeneic pancreatic cancer cell lines and to assess MRI for its applicability in this model.

METHODS

Two cell lines, 6606PDA and Panc02, were employed for the experiments. Cell proliferation and migration were monitored in vitro. Matrigel™ was tested for its role in tumor induction. Tumor cell growth was assessed after orthotopic injection of tumor cells into the pancreatic head of C57/BL6 mice by MRI and histology.

RESULTS

Proliferation and migration of Panc02 were significantly faster than those of 6606PDA. Matrigel did not affect tumor growth/migration but prevented tumor cell spread after injection thus avoiding undesired peritoneal tumor growth. MRI could reliably monitor longitudinal tumor growth in both cell lines: Panc02 had a more irregular finger-like growth, and 6606PDA grew more spherically. Both tumors showed local invasiveness. Histologically, Panc02 showed a sarcoma-like undifferentiated growth pattern, whereas 6606PDA displayed a moderately differentiated glandular tumor growth. Panc02 mice had a significantly shorter (28 days) survival than 6606PDA mice (50 days).

CONCLUSION

This model closely mimics human pancreatic cancer. MRI was invaluable for longitudinal monitoring of tumor growth thus reducing the number of mice required. Employing two different cell lines, this model can be used for various treatment and imaging studies.

Expression of intercellular adhesion molecule (ICAM)-1 or ICAM-2 is critical in determining sensitivity of pancreatic cancer cells to cytolysis by human gammadelta-T cells: implications in the design of gammadelta-T-cell-based immunotherapies for pancreatic cancer

BACKGROUND AND AIMS

gammadelta-T cells can recognize and kill malignant cells, particularly those of epithelial origin, through mechanisms which do not require the recognition of tumor-specific antigens (innate immune response). This natural ability of gammadelta-T cells to kill tumor cells in a tumor antigen-independent manner provides a strong rationale for developing clinical trials designed to exploit the innate antitumor properties of gammadelta-T cells.

METHODS

In vitro studies were carried out to asses the sensitivity of pancreatic cancer cells (MIA PaCa2, BxPC-3, PANC-1) to killing by ex vivo expanded human gammadelta-T cells.

RESULTS

The capacity of gammadelta-T cells to bind to as well as to kill pancreatic cancer cells correlated with the degree of surface expression of key intercellular adhesion molecules (ICAM) present on pancreatic cancer cells. Moreover, pancreatic cancer cells expressing neither ICAM-1 nor ICAM-2 were bound poorly by gammadelta-T cells and were found to be resistant to gammadelta-T-cell killing. However, upon transfection of resistant cells with ICAM-1 or ICAM-2, gammadelta-T cells were then able to bind to and subsequently kill these cells.

CONCLUSION

In vitro, the expression of ICAM-1 or ICAM-2 on human pancreatic cancer cells is critically important in determining the extent to which these cells are sensitive to killing by human gammadelta-T cells. Accordingly, in ongoing and future clinical studies using gammadelta-T cells for the treatment of a variety of epithelial-derived solid tumors-including pancreatic cancer-interventions intended to modulate ICAM expression on tumor cells may become important adjuncts to gammadelta-T-cell-based immunotherapies.

Amplification of the lytic potential of effector/memory CD8+ cells by vector-based enhancement of ICAM-1 (CD54) in target cells: implications for intratumoral vaccine therapy

We demonstrated that enhanced expression of the costimulatory molecules CD80, CD54 and CD48 (designated rF-TRICOM) on target cells, as delivered via a recombinant fowlpox vector, results in an increased state of stimulation of CD8+ T cells, and consequent increased lysis of target cells. CTL studies in conjunction with antibody-blocking studies demonstrated that the enhanced effector activity of these CD8+ T cells is mediated mainly through CD54. Intracellular staining of CD8+ cells that interact with target cells infected with rF-TRICOM showed that they contain higher amounts of perforin and have a higher level of perforin message. Enhanced expression of costimulatory molecules (specifically CD54) on target cells using rF-TRICOM vectors also leads to the formation of stable conjugates/synapses between targets and T cells. The interaction of T cells with target cells that overexpress costimulatory molecules upon infection with rF-TRICOM leads to enhanced signaling through Lck, ZAP70, and STAT-1 in CD8+ T cells and heightened lytic activity of CD8+ cells through the formation of a greater number of immunological synapses. This, in turn, leads to enhanced signaling in T cells. Finally, studies were conducted in mice in which CEA is a self-antigen in an attempt to understand the potential clinical relevancy of intratumoral vaccine therapy. Mice were transplanted subcutaneously with CEA expressing tumors. Intratumoral (i.t.) vaccination was administered 8 days post tumor transplant. Mice vaccinated i.t. with rF-TRICOM demonstrated significantly reduced tumor growth and 40% of the mice had complete tumor regression. The antitumor effects were further improved by the addition of tumor antigen (CEA) in the vaccination by utilizing rF-CEA/TRICOM, with 80% of the mice experiencing complete tumor regression. These studies thus support the concept of intratumoral vaccination employing vectors expressing costimulatory molecules.

Activation requirements of circulating antigen-specific human CD8(+) memory T cells probed with insect cell-based artificial antigen-presenting cells

We sought to define the molecular setup of an antigen-presenting cell that elicits antigen-specific T cell responses in vitro using insect cells that were infected with recombinant baculoviruses. Expression of single-chain HLA was complemented step-by-step with costimulatory molecules, including CD54 and CD80, by co-infection with the relevant viruses. Role of CD8 was assessed by introducing hybrid class I molecules where the alpha-3 domain of the HLA heavy chain molecule was replaced by its murine K(b) counterpart. Circulating T cells that respond to the EBV-derived HLA-A2-restricted peptide GLGCTLVAML were previously shown to bear hallmarks of memory cells. We found that the HLA+peptide complex alone displayed on the surface of insect cells was sufficient to elicit IFN-gamma secretion from these freshly isolated CD8(+) T cells in ELISpot assays. Binding of CD8 was absolutely required, but coexpression of costimulatory molecules resulted only in minimal increase in the number of spots. Tumor antigen-specific CTL clones also reacted in a strictly antigen-specific manner, but required CD54 for quantitative responses. The amount of IFN-gamma produced by the individual reactive T cells was evaluated as spot size, and was also influenced by the costimulatory molecules: CD54 increased also the response magnitude of cultured CTL lines, while CD80 enhanced cytokine release from freshly isolated CD8(+) T cells. Understanding the stimulatory requirements of functionally competent effector/memory T cells and their exact enumeration will be helpful for increasing the efficacy of vaccines.

Functional balance between T cell chimeric receptor density and tumor associated antigen density: CTL mediated cytolysis and lymphokine production

Genetically engineered expression of tumor-specific single chain antibody chimeric receptors (ch-Rec) on human T lymphocytes endow these cells with the parental monoclonal antibody (mAb) dictated tumor specificity and may be useful for clinical immuno-genetherapy. Therefore it was of importance to assess how the densities of tumor-specific receptors and tumor associated antigens (TAA), respectively, affect primary human T lymphocyte functions in relation to target cell susceptibilities to lysis. We therefore studied the functional balance between ch-Rec densities on human T lymphocytes and TAA on tumor cells. The gene construct encoding a ch-Rec derived from (1) a renal carcinoma cell (RCC) specific mouse mAb (G250), and (2) the human signal transducing Fc(epsilon)RI gamma-chain was used. To obtain ch-RecHIGH-POS and ch-RecLOW-POS T lymphocytes, two distinct retroviral vectors were used to introduce the gene constructs into primary human T lymphocytes. Levels of ch-Rec-redirected T lymphocyte mediated tumor cell lysis, as well as lymphokine production were determined using RCC lines as target/stimulator cells, which express either no or increasing densities of the TAA. A functional and dynamic balance between ch-Rec densities on cytotoxic T lymphocytes (CTLs) on the one hand and TAA densities on RCCs on the other, was found. In short, ch-RecHIGH-POS CTLs are triggered by TAAHIGH-POS as well as TAALOW-POS RCCs to lyse tumor cells and produce (IFN-gamma and TNF-alpha) lymphokine. In contrast, ch-RecLOW-POS T lymphocytes are only triggered for cytolysis and lymphokine production by relatively TAAHIGH-POS RCCs. In conclusion, (1) the activation of T lymphocyte responses is co-determined by the expression levels of the ch-Rec on T lymphocytes and the TAA on tumor cells and (2) at relatively high T lymphocyte ch-Rec expression levels the CTLs lyse tumor cells with a wide range of TAA densities. Gene Therapy (2000) 7, 35-42.

Bispecific agents target endogenous murine T cells against human tumor xenografts

A variety of immunological approaches to cancer treatment are currently being explored. These include strategies designed to enhance or redirect the activity of T cells against tumors. Bispecific antibodies comprise a class of agents capable of redirecting T cells by binding to a tumor antigen and the T-cell receptor (TCR). In vivo pre-clinical testing of bispecific antibodies against human tumors has to date been limited to the use of immunodeficient mice that receive the bispecific agent, activated human effector T cells, and human tumor cells. In this report, we show that TCR transgenic/RAG-1 knockout mice (TCR/RAG) serve as a unique model allowing endogenous T cells to be redirected against transplanted human tumors. The findings show that TCR/RAG mice (i) accepted transplants of human tumors, including the folate-receptor-positive tumor line KB; (ii) contained endogenous cytotoxic T lymphocytes that could be activated in vivo with an antigenic peptide recognized by the transgenic TCR; (iii) rejected human tumors after treatment with the activating peptide and bispecific agents that contained folic acid co-valently linked to an anti-TCR antibody. Successful rejection was achieved with folate conjugates of Fab or scFv fragments. Treatment with activating agents and bispecific conjugates resulted in the complete eradication of freshly transplanted tumors as well as significantly prolonging the survival of mice bearing established solid tumors. Our results highlight the importance of including T-cell-activating modalities in combination with bispecific antibodies. Additionally, we introduce a system that allows endogenous T cells to be redirected against human tumor xenografts and in which the T cells may be followed in vivo by use of a clonotypic marker.

Expression of ICAM-1 during IFN-alpha-based treatment of metastatic malignant melanoma: relation to tumor-infiltrating mononuclear cells and regressive tumor changes

Intercellular adhesion molecule-1 (ICAM-1) plays an important role in cell to cell interactions. In malignant melanoma, ICAM-1 expression correlates with malignant behavior. We used monoclonal antibodies, anti-ICAM-1, anti-CD4+, anti-CD8+, and anti-CD11c+ to study the effect of interferon-alpha (IFN-alpha) on the expression of ICAM-1 by melanoma cells in regional metastases and its correlation to the occurrence of CD4+, CD8+, and CD11c+ cells close to tumor cells and in the tumor stroma. We also estimated the expression of ICAM-1 and regressive changes in malignant melanoma metastases, correlating the duration of treatment to these effects of IFN-alpha. Twenty-three IFN-alpha-treated and 10 untreated patients with regional metastatic malignant melanoma were studied. The duration of IFN-alpha treatment influenced the expression of ICAM-1. In metastases from patients treated for 1 week only, 1 of 5 showed high expression of ICAM-1 compared with 6 of 11 of those treated for 3 weeks (p = 0.01, chi-square test for trend comparing untreated patients and patients with various durations of IFN-alpha treatment). In IFN-alpha-treated patients with low expression of ICAM-1, none of 7 metastases showed CD4+ cells infiltrating close to tumor cells, in contrast to 6 of 10 metastases expressing high amounts of ICAM-1 (p = 0.03). Similarly, the expression of ICAM-1 was found to correlate with the occurrence of CD8+ cells close to the tumor cells (p = 0.04). We also showed a correlation between ICAM-1 expression and histologic evidence of tumor regression (p = 0.02).

Pancreatic cancer cells can evade immune surveillance via nonfunctional Fas (APO-1/CD95) receptors and aberrant expression of functional Fas ligand

BACKGROUND

The Fas (APO-1/CD95) receptor/Fas ligand (FasR/FasL) system plays a key role in immune surveillance. We investigated the possibility of a tumor escape mechanism involving the FasR/FasL system in pancreatic cancer cells.

METHODS

Fourteen pancreatic cancer cell lines and 3 pancreatic cancer surgical specimens were studied for their expression of FasR and FasL by flow cytometry, immunoblotting, and immunohistochemistry, FasR function was tested with an anti-FasR antibody. FasL function was assessed by coculture assays using pancreatic cancer cells and FasR-sensitive Jurkat T-cells.

RESULTS

FasR was expressed in normal pancreas, in 14 of 14 pancreatic cancer cell lines, and in 3 of 3 surgical specimens. However, only 1 of 14 cancer cell lines expressed functional FasR when grown in monolayer, although 3 additional cell lines displayed functional FasR when cultured in suspension. Normal pancreas did not express FasL, whereas 14 of 14 cancer cell lines and 3 of 3 surgical specimens expressed FasL. FasL expressed by pancreatic cancer cells mediated killing of Jurkat T-cells in coculture assays (P < .005).

CONCLUSIONS

These data suggest that pancreatic cancer cells have 2 potential mechanisms of evading Fas-mediated immune surveillance. A nonfunctional FasR renders them resistant to Fas-mediated apoptosis. The aberrant expression of functional FasL allows them to "counterattack" activated Fas-sensitive T-cells. Alone or in unison, these tumor escape mechanisms may contribute to the malignant and often rapid course of pancreatic cancer disease.

Chimeric scFv/gamma receptor-mediated T-cell lysis of tumor cells is coregulated by adhesion and accessory molecules

Adhesion and accessory molecules play a critical role in T-cell activation and effector function in general and in tumor cell recognition and lysis in particular. We investigated the contribution of CD2, CD3, CD11a/CD18, CD54 and CD58 molecules in T lymphocyte-tumor cell interactions mediated by chimeric immunoglobulin receptors. The chimeric receptor is composed of a single chain antibody binding site and a gamma-chain signal transducing molecule (scFv/gamma). T lymphocytes expressing such scFv/gamma receptors recognize the G250 Ag on renal cell carcinoma (RCC) in an major histocompatibility complex (MHC)-unrestricted manner and exert RCC selective cytolysis. A coregulatory role for CD2, CD3 and CD11a/CD18 molecules in scFv/gamma-mediated cytolysis was demonstrated using monoclonal antibody (MAb)-induced inhibition of scFv/gamma-mediated cytolysis. The inhibition of lysis was not due to inhibition of cytotoxic T lymphocyte (CTL)-target cell conjugation but rather to a post-conjugate signaling event. Binding of CD54 and CD58 MAbs to the RCC did not inhibit cytolysis of RCC cells that expressed high levels of both CD54 and the G250 antigen (Ag) (A75), whereas cytolysis of RCC expressing intermediate levels of CD54 and G250 Ag (SK-RC-17 cl.4) was partly inhibited by the CD54 MAb. Binding of low concentrations of G250 MAb to RCC (A75) rendered these cells sensitive to CD54 MAb inhibition, demonstrating a direct functional relation between G250 Ag expression level and adhesion molecules. Taken together, our findings indicate a coregulatory role for CD2, CD3 and CD11a/CD18 molecules in the scFv/gamma-mediated cytolysis of tumor cells and show that the requirement of CD11a/CD18-CD54 interactions is dependent on the level of free Ag. This make these gene-transduced T lymphocytes attractive tools for adoptive immunogene therapy of cancer.

Expression and prognostic significance of immunoregulatory molecules in esophageal cancer

Major histocompatibility complex molecules (HLA), the co-stimulatory molecule B7 and the intercellular adhesion molecule 1 (ICAM-1) are key molecules involved in T cell-mediated immune surveillance. We aimed at assessing the expression pattern of these immunoregulatory molecules on primary esophageal carcinomas and evaluating their prognostic significance. Representative samples of primary tumors were obtained from 53 patients who had undergone radical en bloc esophagectomy without residual tumor. Cryostat sections of these tumors were stained with monoclonal antibodies (MAbs) directed against either HLA class I, HLA class II, B7 or ICAM-1. The median follow-up was 19 months (range, 6-43). We found that HLA class I expression was deficient on 27 tumors, while a significant neo-expression of HLA class II, B7 and ICAM-1 (> or =25% positive tumor cells) was observed on 17, 29 and 25, tumors, respectively. Kaplan-Meier analyses revealed a significant beneficial influence on relapse-free survival for patients with tumors expressing HLA class I, HLA class II and B7. Cox's regression analyses demonstrated that co-expression of HLA class I and ICAM-1 was a significant and independent predictor of a reduced risk of developing tumor recurrence, whereas expression of ICAM-1 on HLA class I negative tumors was correlated with an increased risk of tumor relapse.

Expression of ICAM-1 enhances in vivo lymphocyte adhesion in a murine fibrosarcoma

BACKGROUND AND OBJECTIVES

ICAM-1 is essential for lymphocyte-endothelial cell interactions. We have demonstrated that increased expression of ICAM-1 in tumors results in an enhanced response to adoptive immunotherapy. We undertook this study to determine whether increased expression of ICAM-1 results in increased lymphocyte adhesion in vivo.

METHODS

Parental MCA-105 tumor cells were cotransfected with ICAM-1 and the NeoR plasmid. A neomycin resistant clone (Cl149) was selected and increased expression of ICAM-1 confirmed by FACS analysis. Tumor fragments (MCA-105 or Cl149) were placed in a dorsal skin-fold chamber on day 0 in C57BL/6 mice. Lymphocytes were fluorescently labeled using 0.5% acridine orange and activity recorded on videotape at 700x magnification. Lymphocyte activity was quantitated over 30 second intervals in postcapillary venules as either passing or rolling/sticking (R/S). The % R/S was calculated for each category and evaluated using chi 2 analysis.

RESULTS

Whereas 38% of lymphocytes were classified as R/S in normal tissue, 32% were classified as R/S (P > .05) in the MCA-105 tumor. However, in the ICAM-1 transfected CL149, there was significantly greater R/S at 53% (P < .05).

CONCLUSIONS

These data demonstrate increased lymphocyte adhesion in tumors with enhanced expression of ICAM-1 by direct in vivo observations and may partially explain the salutary effect of increased ICAM-1 expression on adoptive immunotherapy. This suggests the possible application of adhesion molecule expression in the cellular therapy of cancer.

Expression of MHC molecules and ICAM-1 on non-small cell lung carcinomas: association with early lymphatic spread of tumour cells

Early microdissemination of tumour cells determines the prognosis of patients with apparently localised non-small cell lung cancer (NSCLC). Monoclonal antibodies to epithelial antigens can now be used to detect single carcinoma cells present in mesenchymal secondary organs such as bone marrow or lymph nodes. The present study was designed to obtain insights into the potential role of the immune system in lymphatic and haematogenous microdissemination of NSCLC cells. Using immunohistochemical staining of primary NSCLC, we assessed the expression pattern of molecules mediating an efficient cellular immune response, that is, MHC class I and class II antigens and the intercellular adhesion molecule-1 (ICAM-1). All 58 patients evaluated were staged as free of overt metastases by conventional clinico-pathological screening. Isolated tumour cells in bone marrow or lymph nodes were identified with mAb CK2 to cytokeratin component No. 18 and mAb BerEp-4 to glycoproteins of 34 and 39 kd present on epithelial cells, respectively. MHC class I expression on primary tumours was reduced or absent in 6/10 (60.0%) patients with isolated cancer cells in lymph nodes as compared to 6/33 tumours (18.1%) without such tumour cell dissemination (P = 0.01). MHC class II molecules on primary tumours were detected in 1/10 (10.0%) patients with micrometastases to regional lymph nodes and in 10/33 (30.3%) patients without such a tumour cell spread. None of the 10 patients with nodal microdissemination expressed ICAM-1 on their primary NSCLC, while such expression was detectable in 12/33 (36.4%) patients without this dissemination (P = 0.01). In contrast, the detection of tumour cells in bone marrow was not correlated to the expression of any of these immunoregulatory molecules. Our data suggest that escape caused by deficient expression of MHC class I antigens and ICAM-1 on tumour cells may support homing or survival of disseminated tumour cells in lymphoid tissue.

Interferon-alpha-induced protection of renal cell cancer cell line from lysis by natural killer cells and increase of susceptibility by treatment with 5-fluorouracil

We have shown previously that interferon (IFN)-alpha reduces the sensitivity of renal cell cancer (RCC) cell lines ACHN and KRC/Y to lysis by lymphokine-activated killer (LAK) cells. The close relationship between natural killer (NK) cells and LAK cells prompted us to investigate whether IFN-alpha pretreatment also affects the sensitivity of ACHN cells to lysis by NK cells or IFN-alpha-activated NK cells. A 51Cr-release cytotoxicity assay demonstrated that pretreatment of ACHN with IFN-alpha decreased their susceptibility to NK cells and IFN-alpha-activated NK cells in a dose-dependent manner. Moreover, to investigate the usefulness of 5-fluorouracil (5FU) for combination with IFN-alpha therapy, we examined the effect of preincubation with 5FU on the susceptibility of ACHN. IFN-alpha-induced protection of ACHN from lysis by IFN-alpha-activated NK cells weakened in the presence of 5FU at 0.2 microgram/ml. An adhesion assay showed that preincubation of ACHN with 5FU and IFN-alpha did not alter the adhesion of IFN-alpha-activated NK cells. A cold target competition analysis did not show any difference between untreated and 5FU and/or IFN-alpha-treated competitors. These results suggest that one of the mechanisms of 5FU for combination with IFN-alpha therapy might depend on changes of RCC cells in intrinsic lysability involving a post-binding stage of the lytic cycle to NK cells.

Expression on leukemic cells and serum circulating levels of intercellular adhesion molecule-1 (ICAM-1) in B-cell chronic lymphocytic leukemia: implications for prognosis

Expression of intercellular adhesion molecule-1 (ICAM-1) has been correlated clinical and laboratory characteristics of 62 patients with untreated CD5+ chronic lymphocytic leukemia (CLL). ICAM-1 was detected on B-CLL cells from 19 out of 62 patients (30.6%) and its expression did not correlate with the majority of immunological markers. An important finding of this study was the association between ICAM-1 expression and mean fluorescence intensity (MFI) of Slg (r = 0.507; P < 0.001). As far as correlation with clinical parameters is concerned, a statistically significant association between Binet clinical stages and ICAM-1 expression was found (P < 0.05). Furthermore, an atypical CLL morphology was more frequently encountered among patients who expressed ICAM-1 (P < 0.005). To obtain more information on the role of ICAM-1 in CLL we measured serum levels with a sandwich enzyme immunoassay. In 47 B-cell CLL patients studied, the mean value of circulating ICAM-1 levels was significantly higher (561 +/- 201 ng/ml) than that observed in 25 normal controls (353 +/- 162 ng/ml; P < 0.005); a clear correlation being found with Binet clinical stages (P = 0.026) and bone marrow (BM) histology (P < 0.005). We conclude that circulating ICAM-1 is elevated in CLL and such an increase reflects tumor mass as defined by clinical stages and BM histology, rather than peripheral blood lymphocytosis (r = 0.240). Even if soluble ICAM-1 appears to be less specifically increased that soluble CD23 serum levels, these circulating molecules were not completely independent of each other (r = 0.512; P < 0.001).

Anti-leukocyte function-1 antibody treatment prevents the rejection of intraocular regressor tumors and their metastases

The role of the cell adhesion molecules, LFA-1 and ICAM-1, in intraocular tumor rejection was examined using four different syngeneic intraocular regressor tumors and four different inbred mouse strains. All four tumors undergo T cell-dependent immune rejection in the syngeneic host. Two of the tumors, D5.1G4 melanoma and P91 mastocytoma, undergo rejection by a cytotoxic T lymphocyte-like immune process. The other two tumors, UV5C25 fibrosarcoma and 124E2 melanoma, are rejected by a process that appears to be mediated by delayed-type hypersensitivity. Systemic administration of anti-LFA-1 prevented the rejection of all four categories of tumors. By contrast, similar in vivo treatment with anti-ICAM-1 antibody did not inhibit tumor rejection. The effect of anti-LFA-1 and anti-ICAM-1 antibody treatment on the rejection of metastases arising from intraocular P91 tumors was also examined and found to be highly dependent upon normal LFA-1 function since antibody treatment with anti-LFA-1 prevented the rejection of metastases. Treatment with anti-ICAM-1 antibody alone had no appreciable effect on the rejection of metastases. The results from this study indicate that the expression and function of LFA-1 is crucial for the generation of immune responses to tumor antigens originating within the eye and the expression of tumor immunity within the eye and at distant sites.

Tumor heterogeneity and immunotherapy of cancer

Tumor heterogeneity is the presence of intercellular differences, either from clonal origin or present within subpopulations of tumor cells. Recent advances in immuno-histology, flow cytometric analysis, molecular biological techniques, and tissue culture methods makes it possible to investigate tumor heterogeneity in detail. In this review data are presented to document that this hallmark of neoplastic disease results from DNA-instability and the interactions of tumor cells with their environment. The present inability to treat most patients effectively with immunotherapy may partly be due to the occurrence of tumor heterogeneity. Therefore, the heterogeneity of the tumor phenotype is discussed in conjunction with the various immunotherapeutic treatment modalities. In addition to local cytokine production by immune cells and tumor cells, and limited access of either antibodies or immune cells into the tumor, tumor heterogeneity is an important factor that determines the progress of immunotherapy of cancer. Therefore, accurate quantitative methods using antibodies and molecular probes to identify HLA-associated target peptides, tumor-associated antigens and accessory molecules, to predict which patients will have a high probability of responding to treatment, are needed.

The role of CD4+ tumor-infiltrating lymphocytes in human solid tumors

Many, if not all, solid tumors are characterized by a T cell infiltrate, usually consisting of CD4+ and CD8+ T cells. Characterization of both subsets of tumor-infiltrating lymphocytes (TIL) have shown that each population can be divided into tumor-specific and tumor-nonspecific T cells. A small proportion of tumor-specific CD4+ TIL can directly lyse tumor cells in an HLA class I- or II-restricted fashion. The majority of tumor-specific CD4+ TIL, however, recognize tumor antigens presented on HLA class II molecules by antigen-presenting cells (APC). At the same time, APC in the tumor environment express elevated levels of heat shock antigen (Hsp) 70 (and perhaps other antigens) that can be specifically recognized by tumor-nonspecific CD4+ TIL when presented by HLA class II. Functionally, CD4+ T cells can be distinguished into Th0 (production of IL-2, IL-4, and IFN-gamma), Th1 (IL-2 and IFN-gamma), and Th2 (IL-4). In addition, stressed CD4+ TIL have the ability to produce the growth factors heparin binding epidermal growth factor and basic fibroblast growth factor that support tumor growth. Since the efficacy of an antitumor immune response is codetermined by the net effect of stimulatory and inhibitory cytokines, a detailed understanding of the developmental pathways of CD4+ TIL subsets and their interactions is critical for the design of clinical protocols.

Phase I study of intravenously applied bispecific antibody in renal cell cancer patients receiving subcutaneous interleukin 2

In a phase I trial the toxicity and immunomodulatory effects of combined treatment with intravenous (i.v.) bispecific monoclonal antibody BIS-1 and subcutaneous (s.c.) interleukin 2 (IL-2) was studied in renal cell cancer patients. BIS-1 combines a specificity against CD3 on T lymphocytes with a specificity against a 40 kDa pancarcinoma-associated antigen, EGP-2. Patients received BIS-1 F(ab')2 fragments intravenously at doses of 1, 3 and 5 micrograms kg-1 body weight during a concomitantly given standard s.c. IL-2 treatment. For each dose, four patients were treated with a 2 h BIS-1 infusion in the second and fourth week of IL-2 therapy. Acute BIS-1 F(ab')2-related toxicity with symptoms of chills, peripheral vasoconstriction and temporary dyspnoea was observed in 2/4 and 5/5 patients at the 3 and 5 micrograms kg-1 dose level respectively. The maximum tolerated dose (MTD) of BIS-1 F(ab')2 was 5 micrograms kg-1. Elevated plasma levels of tumour necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) were detected at the MTD. Flow cytometric analysis showed a dose-dependent binding of BIS-1 F(ab')2 to circulating T lymphocytes. Peripheral blood mononuclear cells (PBMCs), isolated after treatment with 3 and 5 micrograms kg-1 BIS-1, showed increased specific cytolytic capacity against EGP-2+ tumour cells as tested in an ex vivo performed assay. Maximal killing capacity of the PBMCs, as assessed by adding excess BIS-1 to the assay, was shown to be decreased after BIS-1 infusion at 5 micrograms kg-1 BIS-1 F(ab')2. A BIS-1 F(ab')2 dose-dependent disappearance of circulating mononuclear cells from the peripheral blood was observed. Within the circulating CD3+ CD8+ lymphocyte population. LFA-1 alpha-bright and HLA-DR+ T-cell numbers decreased preferentially. It is concluded that i.v. BIS-1 F(ab')2, when combined with s.c. IL-2, has a MTD of 5 micrograms kg-1. The treatment endows the T lymphocytes with a specific anti-EGP-2-directed cytotoxic potential.

Cell surface expression and serum levels of intercellular adhesion molecule-1 in renal cell carcinoma

Intercellular adhesion molecule-1 (ICAM-1) is the natural ligand of the T-lymphocyte adhesion molecule LFA-1 (lymphocyte-function-associated antigen-1). ICAM-1 is involved in target cell recognition by T-lymphocytes, LAK cells and natural killer cells. The molecule has also been detected on a variety of normal cells and on human tumors. Renal cell carcinoma (RCC) is one of the few tumors that respond to immunotherapy, but clinical results are generally disappointing. We therefore analyzed, by immunohistochemistry, the expression of ICAM-1 in pairs of normal kidneys, RCC, and RCC metastases. Moreover, serum ICAM-1 was determined in RCC patients and compared with surface expression of cell-bound ICAM-1. Strong glomerular expression of ICAM-1 was observed in all specimens of normal kidney examined. Proximal tubuli were weakly stained in the majority of specimens. Of the tumors, 80% stained positive for ICAM-1. Although ICAM-1 was detected on the majority of extrarenal tumor specimens examined, staining was generally weaker in the metastases. Patients without metastases at initial presentation more frequently expressed ICAM-1 in their primary tumors than did patients with metastases. Levels of serum ICAM-1 (sICAM-1) were significantly higher in RCC patients than in controls with non-malignant renal diseases. Patients with an unfavorable prognosis, e.g. with advanced tumor stage or metastasis at initial presentation, had higher levels of sICAM-1 than patients with low-grade and/or low-stage tumors.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of major histocompatibility class I and class II antigens and intercellular adhesion molecule-1 on operable non-small cell lung carcinomas: frequency and prognostic significance

Major histocompatibility complex (MHC) antigens and adhesion molecules, such as the intercellular adhesion molecule-1 (ICAM-1), appear to play an important role in the immunological recognition and destruction of tumour cells. We, therefore, examined the expression patterns of these proteins on primary tumours of 91 patients with operable non-small cell lung cancer (NSCLC). Applying immunohistochemistry with monoclonal antibody (MAb) W6/32 against a common framework determinant of HLA class I antigens revealed a deficient expression in 33.0% of the cases analysed, while neo-expression of either HLA class II antigens (MAb TAL.1B5) or ICAM-1 (MAb PA3.58-14) was observed in 26.4 or 29.7% of tumours, respectively. Analysis of consecutive tumour specimens indicated that HLA antigens and ICAM-1 were frequently coexpressed. With regard to clinicopathological risk factors, we could demonstrate a preferential expression of those markers in patients with locally restricted and well-differentiated tumours or no lymph node metastases, which was more pronounced in adenocarcinomas than in squamous cell carcinomas. In contrast, the presence versus the absence of HLA antigens and ICAM-1 was not correlated with the rate of tumour recurrence or overall survival in patients with NSCLC. In conclusion, the co-ordinated expression of immunologically relevant cell surface molecules on primary NSCLC is a frequent event that correlates with distinct parameters of favourable prognosis. However, we have no evidence that the immune response facilitated by these molecules can effectively influence the clinical course of the disease.

T-cell based cancer immunotherapy: direct or redirected tumor-cell recognition?

In development of strategies for immunotherapy of cancer a new emphasis is emerging, termed T-cell retargeting, which involves artificial redirection of cytotoxic T lymphocytes (CTL) against cancer cells, using bispecific reagents. In this article, Gideon Beun, Cornelis van de Velde and Gert Jan Fleuren evaluate this potential strategy for cellular immunotherapy, and propose how the gap between in vitro results and clinical application might be bridged.

5-Fluorouracil increases susceptibility of renal cell cancer cell lines to lymphokine-activated killer cells: evidence for alteration not at the level of recognition but at a post-binding stage of the lytic cycle

To investigate the usefulness of 5-Fluorouracil (5FU) for combination with immunotherapy, we examined the effect of preincubation with 5FU on the susceptibility of a renal cell cancer (RCC) cell line, ACHN, to lymphokine-activated killer (LAK) cells. A 4-h 51Cr release assay showed a remarkable increase in the susceptibility of ACHN cells to LAK cells. Dose response experiments demonstrated that 5FU at concentrations as low as 0.002 microgram/ml increased susceptibility to LAK cells. Presence of 5FU at 2 micrograms/ml but not at 0.2 microgram/ml in media blocked LAK activity induction by IL-2. Furthermore, an adhesion assay showed that preincubation with 5FU did not alter the adhesion of LAK cells to tumor cells nor the expression of intercellular adhesion molecule-1 (ICAM-1), lymphocyte function-associated antigen-3 (LFA-3) or major histocompatibility complex (MHC) class I molecules on tumor cells. Cold target competition did not show any difference between 5FU-treated and untreated competitors. These results suggest that increased susceptibility of RCC cells to LAK cells due to preincubation with 5FU might depend on changes in intrinsic lysability involving a post-binding stage of the lytic cycle.

Local antitumour treatment in carcinoma patients with bispecific-monoclonal-antibody-redirected T cells

In a pilot clinical study carcinoma patients with malignant ascites or pleural exudates have been treated locally with autologous lymphocytes activated ex vivo and redirected towards tumour cells with bispecific monoclonal antibodies. BIS-1, the bispecific monoclonal antibody used in this study, combines specificity against a tumour-associated antigen, AMOC-31, present on carcinomas, with a specificity against the CD3 complex on T lymphocytes. Patients selected for treatment had malignant pleural or peritoneal effusions. Treatment consisted of isolating autologous peripheral blood lymphocytes, ex vivo activation, incubation with bispecific monoclonal antibodies and injection at the effusion site of these BIS-1-redirected lymphocytes. To evaluate the effects of the bispecific monoclonal antibody, five patients received treatments with activated lymphocytes without bispecific antibodies. Effusion samples taken before and at various times after treatment were analysed by immunocytology and for the presence of the soluble factors carcinoembryonic antigen (CEA), interleukin-6 (IL-6), tumour necrosis factor (TNF), C-reactive protein and soluble CD8. In this way both immune activation and anti-tumour activity could be monitored. Conjugate formation between tumour cells and activated lymphocytes was seen as soon as 4 h after injection of BIS-1-redirected activated lymphocytes, followed by a disappearance or reduction of tumour cells after 24-48 h. In parallel with this, the soluble tumour marker CEA decreased in the effusion fluid following injection with the BIS-1-redirected lymphocytes. Furthermore, a steep increase in local granulocyte numbers was observed in the effusion fluid, which reached a maximum 24-48 h after the start of the treatment. Also levels of IL-6 and TNF were greatly elevated. The data suggest that the treatment induces both antitumour activity and a strong local inflammatory reaction. This is accompanied by no or only minor local and systemic toxicity, i.e. mild fever, which disappeared as the local inflammatory reaction diminished 48-72 h after treatment.

Differential expression and release of LFA-3 and ICAM-1 in human melanoma cell lines

We examined 10 different melanoma cell lines for cellular expression and release of ICAM-1 (CD54) and LFA-3 (CD58) and the influence of cytokines, including IFN alpha, IFN gamma and TNF alpha. Cellular ICAM-1 expression and density varies considerably between the melanoma cell lines. While IFN alpha has no effect on cellular ICAM-1 (cICAM-1) expression, IFN gamma and to a lesser extent TNF alpha can effectively up-regulate cICAM-1. Soluble ICAM-1 (sICAM-1) is detected in the supernatants of all lines tested, release of sICAM-1 correlates with cellular expression. LFA-3 does not much differ in its expression level on melanoma lines, and cytokines have little or no effect on its expression. Soluble LFA-3 is released by only 6 out of 10 lines. Its release can effectively be inhibited by IFN gamma in all lines and by TNF alpha in one, while IFN alpha has no effect. These data show that expression and release of LFA-3 and ICAM-1 differ between melanoma cell lines. This may be of importance for the interaction of melanoma cells with immune effector cells in vivo.

12-O-tetradecanoylphorbol-13-acetate not only modulates proliferation rates, but also alters antigen expression and LAK-cell susceptibility of normal human melanocytes in vitro

For serial cultivation of normal human melanocytes media supplemented with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) are largely employed. By using a culture medium that permits cultivation of melanocytes without TPA, the effects of TPA on melanocyte proliferation, phenotype, and susceptibility to lymphokine-activated killer cells were studied. Addition of 50 ng/ml TPA to the medium induced rapid dendrite formation and increased the cell proliferation rate by 16-63% in mitogen-rich media (four of seven cultures, p < 0.01), and by 237% in mitogen-reduced media (p < 0.001). Furthermore, several phenotypic changes indicating early stages of melanocyte transformation were induced by 50 ng/ml TPA. These included increased expression of melanoma progression-associated antigens such as A.1.43 and A.10.33, upregulation of nerve-growth factor receptor as well as of the melanocyte-activation marker HMB-45 and of histocompatibility class I antigens. In contrast, the expression of the differentiation marker K.1.2 and of intercellular adhesion molecule-1 was decreased in TPA-treated cultures. Most of these changes persisted even after removal of TPA from the culture medium (> or = 2 weeks). Staurosporine, a protein kinase C inhibitor, modulated melanocyte-antigen expression similar to TPA, suggesting that protein kinase C downmodulation rather than activation by TPA is involved. In addition to the antigenic alterations, the susceptibility of TPA-treated melanocytes to lymphokine-activated killer cell cytotoxicity decreased by 40% (p < 0.01), possibly due to their altered surface antigen expression. The presented data reveal that the tumor promoter TPA hitherto used as a supplement of melanocyte culture media induces profound phenotypic and functional changes of the cultured cells, indicating incipient transformation of normal human melanocytes in vitro.

T-cell-receptor engagement and tumor ICAM-1 up-regulation are required to by-pass low susceptibility of melanoma cells to autologous CTL-mediated lysis

Tumor-specific and non-specific CD3+, TcR alpha beta+, CD8+ cytotoxic T-cell (CTL) clones, isolated from tumor-infiltrating lymphocytes (TIL) or peripheral blood lymphocytes (PBL) of a melanoma patient and allogeneic LAK cells, were used to investigate the requirements for bypassing the low lysability of some melanoma clones derived from an s.c. metastasis from which highly lysable clones were also obtained. Cytofluorimetric analysis showed that all melanoma clones expressed ICAM-1, although to different extents, reaching a 10-fold difference in fluorescence units, while HLA class-I antigens were similarly expressed. The differences in expression of ICAM-1 among tumor clones correlated with differences in lysability, by both specific and non-specific CTL, but were not large enough to affect lymphocyte-tumor conjugate formation. Cytokine- or gene-transfer-mediated up-regulation of ICAM-1 did not induce de novo lysis of ICAM-1low tumor cells; however, it markedly enhanced a low level of killing of the same cells by tumor-specific, TcR-dependent and HLA-restricted CTL clones but not by non-specific, TcR-independent effectors. In addition, lysis of melanoma clones by any effector was similarly inhibited by anti-ICAM-1 and anti-LFA-1 antibodies. This indicates that by-pass of low lysability of ICAM-1low melanoma clones by CTL clones, after ICAM-1 up-regulation, is possible only if simultaneous LFA-1 and TcR engagement takes place. In addition, these results suggest that the constitutive high level of expression of ICAM-1 on the subset of ICAM-1high melanoma cells must be only one of the factors contributing to the high lysability of these cells by any effector.

Immunohistochemical detection of intercellular adhesion molecule-1 (ICAM-1) and major histocompatibility complex class I antigens in seminoma

Expression of intercellular adhesion molecule-1 (ICAM-1) and major histocompatibility complex (MHC) antigens, and characterization of tumor-infiltrating mononuclear cells (TIM) were examined immunohistologically in 10 specimens of seminoma. ICAM-1 and MHC antigens were not detected on normal spermatogenic cells. ICAM-1 and MHC class I antigens were variably expressed in 7 and 9 seminomas, respectively, whereas class II antigens were not detected. Although the degree of expression of ICAM-1 and MHC antigens was not correlated with any clinical or histopathological factors, neither of the antigens was detected on an anaplastic seminoma. Various numbers of TIM were detected in all of the seminoma, and comprised mainly T cells bearing the lymphocyte function-associated antigen (LFA)-1. No significant correlation was noticed between the degree of lymphocyte infiltration and ICAM-1 or MHC antigen expression. Although ICAM-1 and MHC class I antigens were expressed in seminoma, possibly facilitating an anti-tumor reaction of host, their expression remained low in several cases, despite marked lymphocyte infiltration within the tumor.

Recognition of shared melanoma antigen by HLA-A2-restricted cytolytic T cell clones derived from human tumor-infiltrating lymphocytes

Three melanoma-specific cytotoxic T lymphocytes (CTL) clones were derived from the tumor-infiltrating lymphocyte (TIL) of human melanoma M17, and were used to study the expression of immunogenic melanoma peptides on allogeneic tumors. Antibody inhibition studies showed that two of these TIL clones were restricted by an HLA-A2 molecule which was identified as A2.1 by gene sequencing. The third CTL clone was not restricted by HLA-A2, but by a B or C HLA antigen. HLA-A2-restricted CTL clones M17-1 and M17-2 lysed 5 and 12 out of 15 HLA-A2+ allogeneic melanomas, respectively. Since they did not lyse autologous Epstein-Barr virus B cells, HLA-A2.1-transfected P815 cells, 13 HLA-A2+ non-melanoma tumor cell lines and 10 HLA-A2- melanomas, these clones appeared specific for melanoma-restricted epitopes presented by the HLA-A2.1 molecule. We then tried to determine why a few HLA-A2+ melanomas were refractory to TIL lysis. By using a combination of flow cytometry analysis, partial cloning and sequencing of their HLA-A2 genes, we show that failure to lyse did not result from low expression or polymorphism of the HLA-A2 molecule, or from deficient expression of the adhesion molecules ICAM-1 and LFA-3 by these melanomas. Taken together, our data confirm at the clonal level the existence of shared melanoma antigens recognized by TIL in the HLA-A2.1 context. They further show that individual peptides derived from these antigens are expressed by a large majority of HLA-A2+ melanomas. Identification of such peptides appears crucial for the future of vaccination therapies.

Killing of human leukaemia/lymphoma B cells by activated cytotoxic T lymphocytes in the presence of a bispecific monoclonal antibody (alpha CD3/alpha CD19)

Bispecific antibodies (BsAb) can be used to retarget T cells irrespective of their specificity to certain target cells inducing target cell lysis. We have tested the efficacy of the BsAb SHR-1, directed against the T cell antigen CD3 and the B cell antigen CD19 to induce (malignant) B cell kill by T cells as measured in a 51Cr-release assay. Two cytotoxic T cell clones (CTL), expressing TCR alpha beta or TCR gamma delta, were effective in killing CD19 expressing B cell lines at different stages of differentiation in the presence, but not in the absence, of the BsAb. CD19- target cells were not killed. Fresh CD19+ leukaemia/lymphoma cells were also efficiently killed by SHR-1 preincubated CTL clones. In addition, phytohaemagglutinin (PHA) or CD3-activated IL-2 expanded peripheral blood mononuclear cells (PBMC) of normal donors did so after 2 weeks of stimulation. A concentration of 100 ng/ml of the BsAb was sufficient to obtain optimal lysis of all target cells tested. These results show that fresh human leukaemia/lymphoma cells, freshly derived from active lymphoblastic leukaemia (ALL) as well as non-Hodgkin's lymphoma (NHL) patients, can be effectively killed in the presence of this BsAb by activated T cells.

Treatment with tumour infiltrating lymphocytes and interleukin-2 in patients with metastatic melanoma: a pilot study

Tumour infiltrating lymphocytes (TIL) were isolated and expanded from biopsy samples of 4 patients with metastatic melanoma. The patients were treated with autologous expanded TIL and continuous or bolus infusion of Interleukin 2 (IL-2) at a dose of 18 x 10(6) International Units/m2/day for 5 days starting 36-48 hours after administration of cyclophosphamide at a dose of 1 g/m2. The number of TIL infused ranged from 10(10) to 5.56 x 10(10) cells. Two patients had stable disease (SD) lasting for 2 1/2 and 4 months respectively and they died 24 and 13 months after therapy. One patient died during therapy due to a pseudomonas septicaemia and another patient developed progressive disease (PD). He died 3 months after the start of therapy. The side effects were substantial but most of them were reversible upon cessation of the treatment. The majority of the expanded TIL of all patients were of the CD8+ phenotype. Cutaneous metastases from two patients, removed after treatment with IL-2 and TIL, showed moderate lymphocytic infiltration also mainly of CD8+ T cells. The treatment with IL-2 and TIL is feasible, but further investigations should continue in an attempt to improve the efficacy of the therapy, to reduce toxicity and to diminish the costs and labour of the culture methods.

Susceptibility of acute myelogenous leukemia blasts to lysis by lymphokine-activated killer (LAK) cells and its clinical relevance

To help understanding host-tumor relationships in acute myelogenous leukemia (AML) and better define indications for interleukin 2 (IL-2) therapy in this disease, we studied the relationship between the susceptibility of leukemic cells of 44 AML patients to lysis by autologous (26 cases) and/or allogeneic (41 cases) lymphokine-activated killer (LAK) cells and characteristics of the leukemia. Lymphocytes were activated in the presence of 1000 u/ml recombinant IL-2 for 5 days. Lysis of AML cells was studied by 51Cr release. Average lysis of AML cells by autologous LAK cells was 9 +/- 13% and by allogeneic LAK cells 10 +/- 9% with a significant correlation between lyses by both effectors (p = 0.01). Autologous (p = 0.005) and allogeneic (p = 0.004) lyses were higher in patients with initial infection. Allogeneic lysis was correlated with initial WBC count (p = 0.009), serum lactic-dehydrogenase level (p = 0.05), and expression of CD13 (p = 0.01). Autologous lysis was inversely correlated with expression of CD34 (p = 0.003). Expression of adhesion molecules CD54 (ICAM-1) and CD58 (LFA-3) by the leukemic cells did not correlate with their lysis by LAK cells. Susceptibility of leukemic cells to lysis by LAK cells did not correlate with prognosis of the leukemia.

Expression of cell adhesion molecules in human melanoma cell lines and their role in cytotoxicity mediated by tumor-infiltrating lymphocytes

The role of cell adhesion molecules (CAM) LFA1, ICAM-1, LFA3, VLA1, VLA4, CD29, CD44, and CD56 in tumor-infiltrating lymphocyte (TIL) and natural killer cell (NK)-mediated killing of target cells was studied. Melanoma cell lines and autologous TIL were derived from seven patients with metastatic melanoma, and cytotoxicity assays were done in the presence and absence of monoclonal antibodies (MoAb) to CAM expressed on melanoma cells or TIL. The melanoma cell lines analyzed were all positive for CD29 and LFA3 expression, negative for LFA1 expression, but showed variable expression of ICAM-1, VLA1, VLA4, CD44, and CD56. The effects of anti-CAM antibodies on TIL-mediated melanoma killing fell into three categories: (1) consistent inhibition of TIL-mediated killing was observed when melanoma cells were pretreated with anti-ICAM1 and anti-LFA-3 MoAb or when TIL were pretreated with anti-LFA1; (2) no effect was observed when melanoma cells were pretreated with anti-CD56; or (3) a discreet, but significant, inhibition was observed when target cells were pretreated with anti-CD29, anti-VLA1, anti-VLA4, and anti-CD44. Cytotoxicity was significantly enhanced by pretreatment of target cells with gamma-interferon (gamma-IFN), although gamma-IFN did not augment surface expression of the CAM studied. The NK-mediated killing of K562 cells was blocked by anti-LFA1, anti-CD18, and anti-ICAM, and partially inhibited by anti-CD44 MoAb. Together, these results suggest that several accessory CAM may play a role in regulating cellular cytotoxicity. Because cytotoxicity generally correlated with the level of expression of CAM in melanoma cells, weak CAM surface expression may provide a means for melanomas to escape immune surveillance.

Interferon gamma but not tumor necrosis factor alpha decreases susceptibility of human renal cell cancer cell lines to lymphokine-activated killer cells

Human renal cell cancer (RCC) cell lines, ACHN and KRC/Y, with or without exposure to cytokines, were examined for their susceptibility to lymphokine-activated killer (LAK) cells. Flow-cytometric analysis demonstrated constitutional expression of class I antigen on both cell lines, which was enhanced by interferon alpha (IFN alpha), IFN gamma and tumor necrosis factor alpha (TNF alpha). A 4-h 51Cr-release cytotoxicity assay demonstrated that pretreatment of both cell lines with IFN gamma or IFN alpha, but not with TNF alpha, decreased their susceptibility to LAK cells. IFN gamma also decreased susceptibility to natural killer cells in a 16-h 51Cr-release cytotoxicity assay. IFN gamma treatment decreased the susceptibility of ACHN cells in a dose-dependent manner. "Cold"-target competition assay clearly showed that IFN gamma- but not TNF alpha-pretreated cells compete less effectively than do untreated target cells. Pretreatment with IFN gamma, however, increased expression of intercellular adhesion molecule-1 (ICAM-1) to a degree comparable to that with TNF alpha. Northern blot analyses using a 520-base-pair ICAM-1 cDNA as a probe demonstrated that more 3.3-kb mRNA is expressed in IFN gamma- and TNF alpha-pretreated cells. These results suggest that IFN gamma-treated RCC cell lines may reduce their ability to be recognized by LAK cells, and that IFN-induced protection of RCC cell lines against LAK cells may depend upon a mechanism independent of the expression of class I antigens or ICAM-1 on tumor cells.

Engineering T lymphocyte antigen specificity

Targeting of immune cells by bispecific antibodies has proven to be a powerful tool for the investigation of cellular cytotoxicity, lymphocyte activation and induction of cytokine production, as well as to represent an innovative form of immunotherapy for the treatment of cancer. The hallmark of this approach is the use of the specificity of monoclonal antibodies to join target and immune cells by virtue of the dual specificity of bispecific antibodies for the two entities. More precisely, the bispecific antibody has two different binding sites, which are capable of recognizing tumor associated antigens on the one hand and lymphocyte activation sites on the other. This process of crosslinking results in the activation of the lymphocyte and triggering of its lytic machinery, as well as lymphokine production. A major advantage of this therapeutic modality is, that use is made of the normal cellular immune defence system and therefore is only associated with minor toxicity. The distinct lymphocyte populations, which can be used for adoptive immunotherapy and the various bispecific antibody preparations, as well as the chimeric immunoglobulin/T cell receptor construction, are the major topics of this review.

Expression of leucocyte adhesion molecules on 66 clinical neuroblastoma specimens

LFA-3, ICAM-1, HLA.ABC and HLA.DR expression was analyzed on 66 neuroblastoma specimens. HLA.ABC was expressed on 26 specimens, HLA.DR on 2, LFA-3 on 20 and ICAM-1 on 10. HLA.ABC and LFA-3 were positive on ganglioneuroblastoma or ganglioneuroma, but they were negative on neuroblastoma, independently of the clinical staging; HLA.ABC and LFA-3 were induced in vivo by chemotherapy in parallel with tumoral cell differentiation, in both the primary and the metastases. The expression of ICAM-1 was restricted to 5 of the 10 low-grade stage-1 or stage-2 specimens, 1 stage-3 specimen, and the primary tumors of 2 patients with stage-4 disease, analyzed hence at diagnosis and after chemotherapy (4 specimens); metastatic cells obtained in 1 of these patients were negative. HLA.ABC and LFA-3 expressed on both mycN-negative and -positive specimens, whereas ICAM-1 was restricted to MYCN-negative specimens. LFA-3 diffusely stained partially differentiated neuroblasts, Schwann cells and ganglion cells. The expression of HLA.ABC on differentiated neuroblasts varied from one sample to another and within the same tumor; Schwann cells were strongly positive, but ganglion cells were negative. In positive samples, ICAM-1 was expressed on differentiated neuroblasts and Schwann cells, but negative on ganglion cells; however, most of the differentiated tumors were ICAM-1-negative, suggesting ICAM-1 induction by unknown local signal. The 4 markers were negative on undifferentiated neuroblasts. The distribution of these 4 markers on clinical specimens was in agreement with their reactivity on fetal tissues, as well as with results obtained on neuroblastoma cell lines before and after in vitro treatment with IFN-gamma.

Cell adhesion molecules of the immunoglobulin supergene family and their role in malignant transformation and progression to metastatic disease

Cell adhesion molecules (CAMs) of the immunoglobulin supergene family may play important roles in tumorigenesis and the development of metastatic disease. In a variety of human malignancies, tumor progression has been observed to be associated with changes in CAM expression. An early event in colorectal tumorigenesis appears to be the down regulation of a normally expressed CAM, DCC. Over-expression of a second CAM, carcinoembryonic antigen, is associated with colorectal tumors which have a high risk for metastasis development. Several tumors, including Wilms tumors and neuroblastoma, have been found to express a developmentally regulated form of NCAM which inhibits a variety of cell-cell interactions. Malignant cells not only show aberrations in the expression of their CAMS and thus their normal cell-cell interactions, but establish new adhesive interactions. The development of metastatic potential in cutaneous melanoma is associated with the de novo expression of two CAMs, one of which is ICAM-1, a molecule mediating adhesion between the tumor cells and leukocytes.

T cell targeting in cancer therapy

Targeting of immune cells by bispecific antibodies has proven a powerful tool for the investigation of cellular cytotoxicity, lymphocyte activation and induction of cytokine production, as well as to represent an innovative form of immunotherapy for the treatment of cancer. The hallmark of this approach is the use of the specificity of monoclonal antibodies to join target and immune cells by virtue of the dual specificity of bispecific antibodies for the two entities. More precisely the bispecific antibody has two different binding sites, which are capable of recognizing tumor associated antigens on the one hand and lymphocyte activation sites on the other. This process of crosslinking results in the activation of the lymphocyte and triggering of its lytic machinery, as well as lymphokine production. A major advantage of this therapeutic modality is, that use is made of the normal cellular immune defence system and therefore is only associated with minor toxicity. The distinct lymphocyte populations, which can be used for adoptive immunotherapy and the various bispecific antibody preparations, as well as the chimeric immunoglobulin/T cell receptor construction are the major topics of this review.