Expression of HLA-DR and common acute lymphoblastic leukemia antigens on glioma cells

Single-Cell Analysis of Refractory Celiac Disease Demonstrates Inter- and Intra-Patient Aberrant Cell Heterogeneity

BACKGROUND & AIMS

Refractory celiac disease type II (RCDII) is a rare indolent lymphoma in the small intestine characterized by a clonally expanded intraepithelial intracellular CD3⁺surfaceCD3^-CD7⁺CD56^- aberrant cell population. However, RCDII pathogenesis is ill-defined. Here, we aimed at single-cell characterization of the innate and adaptive immune system in RCDII.

METHODS

Paired small intestinal and blood samples from 12 RCDII patients and 6 healthy controls were assessed by single-cell mass cytometry with a 39-cell surface marker antibody panel, designed to capture heterogeneity of the innate and adaptive immune system. A second single-cell mass cytometry panel that included transcription factors and immune checkpoints was used for analysis of paired samples from 5 RCDII patients. Single-cell RNA sequencing analysis was performed on duodenal samples from 2 RCDII patients. Finally, we developed a 40-marker imaging mass cytometry antibody panel to evaluate cell-cell interactions in duodenal biopsy specimens of RCDII patients.

RESULTS

We provide evidence for intertumoral and intratumoral cell heterogeneity within the duodenal and peripheral aberrant cell population present in RCDII. Phenotypic discrepancy was observed between peripheral and duodenal aberrant cells. In addition, we observed that part of the aberrant cell population proliferated and observed co-localization of aberrant cells with CD163⁺ antigen-presenting cells (APCs) in situ. In addition, we observed phenotypic discrepancy between peripheral and duodenal aberrant cells.

CONCLUSIONS

Novel high-dimensional single-cell technologies show substantial intertumoral and intratumoral heterogeneity in the aberrant cell population in RCDII. This may underlie variability in refractory disease status between patients and responsiveness to therapy, pointing to the need for personalized therapy in RCDII based on patient-specific immune profiles.

HLA-Dr Expression by Tumor Cells Compared with Survival in High Grade Astrocytomas

Frozen samples from 78 high grade astrocytomas were reacted with a monoclonal antibody directed against HLA-Dr invariant chain. Survival data was obtained for all 78 cases. HLA-Dr was expressed by a proportion of tumor cells in 65/78 (83 %). Comparison of the survival of positive and negative cases showed that the difference was not statistically significant (p = 0.4). The relevance of the finding is discussed in the context of the immunoreaction to brain tumors.

Mononuclear Cell Infiltrate and Hla-Dr Expression in 28 Pituitary Adenomas

Frozen sections from 28 pituitary adenomas were reacted with a panel of monoclonal antibodies to macrophages, lymphocytes and HLA-Dr invariant chain. A low number of macrophages were demonstrated in all tumors, mainly perivascular. CD8 and CD4 lymphocytes were detected in even smaller numbers in 80% and 14% of tumors respectively. B lymphocytes were present in only 1 case. An occasional NK cell was present in 1/13 cases studied. HLA-Dr antigen was expressed by macrophages in all cases and by tumor cells in 2 growth hormone-producing adenomas/19 adenomas. These findings may represent evidence for a low degree of cellular immune response to pituitary adenomas.

Engraftment of C6-2B Cells into the Striatum of Aci Nude Rats as a Tool for Comparison of the in Vitro and in Vivo Phenotype of a Glioma Cell Line

The C6-2B is a well-characterized glioma cell line used extensively in the study of malignant glial biology. While the C6-2B cell line has traditionally been thought of as a homogenous cell line, the in vitro phenotype of the C6-2B cell line can vary considerably depending on the culture technique used and the stratum on which the cells are grown. Thus, we asked whether the in vitro phenotype of the C6-2B cell line was significantly different than the in vivo phenotype of the cell line once it was engrafted into the striatum of nude rats. Under culture conditions used in our laboratory, 100% of the C6 cells were found to express p75, the low-affinity nerve growth factor (NGF) receptor, and Major Histocompatability Class I (MHC Class I), while only 10-15% demonstrated vimentin reactivity. Immunohistochemistry was consistently negative for GFAP, trkA (the high-affinity receptor for NGF), CD4, CD8, and a macrophage specific marker (Ox-41). Once engrafted into the striatum of nude rats, the cells remained 100% p75 and MHC Class I positive, and again, only 15% of the cells demonstrated vimentin reactivity. The grafted cells retained this characteristic for 28 days in vivo. Although an immunoincompetent host was selected to minimize the effects an inflammatory response would have on the graft, a transient inflammatory response was detected. During the first week of engraftment, numerous MHC class II cells, some of which were macrophages, were seen infiltrating the graft. However, by 4 weeks postengraftment, no inflammatory cells were appreciated in the graft and surprisingly little reactive gliosis was seen in the penumbra of the tumor mass. Thus, the limited number of in vitro phe-notypic characteristics we examined in the C6-2B cell line remained constant once the cells were engrafted into the striatum of athymic nude rats.

Use of CD10 as a marker of canine mammary myoepithelial cells

CD10 is an important cell marker in the diagnosis of acute lymphoblastic leukaemia and of breast myoepithelial (ME) cells in humans. The objective of this study was to assess the value of CD10 as a marker of canine ME cells using immunohistochemistry on routinely processed normal, dysplastic and neoplastic mammary tissue. Five different CD10 positive cell types were identified on the basis of cell morphology, pattern of immunoreactivity, and on the co-expression of additional cell lineage-specific markers. Type 1 cells were typical fusiform cells with a ME cell phenotype (calponin- and cytokeratin [CK] 14-positive, CK8/18-negative). Type 2 cells were typical or atypical polyhedral cells with a luminal epithelial (LE) cell phenotype (calponin- and CK14-negative, CK8/18-positive). Type 3 cells had a type 1 phenotype with variable morphology, and type 4 were atypical neoplastic cells with a mixed ME/LE phenotype. Type 5 cells were typical fusiform cells with a stromal phenotype. Type 1 cells were considered normal ME cells and were found in all sample types; type 2 cells were considered normal or neoplastic LE cells and were also found in all sample types; types 3 and 4 cells were restricted to tumour samples and to malignant tumours, respectively, and type 5 cells were found in all sample types, although predominantly in neoplastic tissue. The findings indicate that the CD10 antigen is a sensitive (although not specific) marker of canine ME cells in normal, dysplastic and neoplastic mammary tissue. Differences in the distribution and staining intensity of CD10-positive cells suggest a number of potential roles for this protein in the pathogenesis of canine mammary neoplasia.

CD10 Expression in Pure Stromal and Sex Cord-Stromal Tumors of the Ovary

CD10 has been recently advocated as a good immunohistochemical marker for endometrial stromal tumors. Metastatic endometrial stromal tumors to the ovary and primary endometrioid stromal sarcomas may show overlapping histological features with pure stromal and sex cord-stromal tumors (SCSTs). We investigated CD10 expression in a large series of pure stromal and SCSTs of the ovary to ascertain whether CD10 may aid in this differential diagnosis. Archival material from 11 fibromas, 10 thecomas, 10 sclerosing stromal tumors (SSTs), 10 adult granulosa cell tumors (AGCTs), 4 luteinized AGCTs, 9 juvenile granulosa cell tumors (JGCTs), 9 Sertoli cell tumors, 9 Sertoli-Leydig cell tumors, 11 sex cord tumors with annular tubules, 10 steroid cell tumors (StCTs), and 8 fibrosarcomas of the ovary were immunostained for CD10. The percentage of cells stained (<5%, 5%-39%, 40%-75%, and >75%) and intensity of staining (1+, 2+, 3+) were evaluated. CD10 was expressed in 7 of 10 thecomas (4 with 5%-75% and mostly 1+), 9 of 10 SSTs (7 with 5%-39% + cells, mostly 1+), 9 of 10 AGCTs (<5%-39%, four 1+, five 2+), 1 of 4 luteinized AGCTs (<5% and 1+), 8 of 9 JGCTs (mostly <5% to 39% and +1), 4 of 9 Sertoli cell tumors (either focal or >75% with variable intensity), 4 of 9 Sertoli-Leydig cell tumors (mostly <10% with variable staining), with the Leydig cells being positive in only 1 tumor (1+ and <5%), and 7 of 10 StCTs (4 tumors with more than 75% + cells, from 1+ to 3+). All fibromas, all but 1 fibrosarcoma (<5% and 1+), and all sex cord tumors with annular tubules were CD10 negative. CD10 expression was frequently seen in StCTs, SSTs, and thecomas of the ovary, although the latter 2 categories usually showed only faint immunoreactivity. In conclusion the frequency and intensity of CD10 immunoreactivity in pure stromal and sex cord-stromal ovarian tumors are low and contrast with the typical strong and diffuse immunostaining seen in endometrial stromal tumors; however, faint CD10 positivity is consistent with the diagnosis of ovarian SCST. Steroid cell tumors are often positive for CD10, but these tumors do not pose problems in differential diagnosis with endometrial stromal tumors. CD10 may play a useful role in aiding the differential between endometrial stromal tumors in the ovary and SCST and stromal tumors.

Cellules dendritiques et gliomes : un espoir en immunothérapie ?

Immunotherapy has been explored for several decades to try to improve the prognosis of gliomas, but until recently no therapeutic benefit has been achieved. The discovery of dendritic cells, the most potent professional antigen presenting cells to initiate specific immune response, and the possibility of producing them ex vivo gave rise to new protocols of active immunotherapy. In oncology, promising experimental and clinical therapeutic results were obtained using these dendritic cells loaded with tumor antigen. Patients bearing gliomas have deficit antigen presentation making this approach rational. In several experimental glioma models, independent research teams have showed specific antitumor responses using these dendritic cells. Phase I/II clinical trials have demonstrated the feasibility and the tolerance of this immunotherapeutic approach. In neuro-oncology, the efficiency of such an approach remains to be established, similarly in oncology where positive phase III studies are missing. Nevertheless, dendritic cells comprise a complex network which is only partially understood and capable of generating either immunotolerance or immune response. Numerous parameters remain to be explored before any definitive conclusion about their utility as an anticancer weapon can be drawn. It seems however logical that immunotherapy with dendritic cells could prevent or delay tumor recurrence in patients with minor active disease. A review on glioma and dendritic cells is presented.

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.

Stromal CD10 expression in mammary fibroadenomas and phyllodes tumours

BACKGROUND/AIMS

CD10 (CALLA) has recently been reported to be expressed in spindle cell neoplasia, and has been used to differentiate endometrial stromal sarcoma from leiomyoma and leiomyosarcoma. In the breast, myoepithelial cells express CD10, but there are few studies of the expression of CD10 in mammary fibroepithelial lesions.

METHODS

Stromal CD10 expression was studied in 181 mammary phyllodes tumours (102 benign, 51 borderline malignant, and 28 frankly malignant) and 33 fibroadenomas using immunohistochemistry, to evaluate whether differences in expression correlated with the degree of malignancy.

RESULTS

There was a progressive increase in the patients' age and tumour size, from fibroadenoma to phyllodes tumours with an increasing degree of malignancy (p < 0.001). Stromal CD10 expression was positive in one of 33 fibroadenomas, six of 102 benign phyllodes tumours, 16 of 51 borderline malignant phyllodes tumours, and 14 of 28 frankly malignant phyllodes tumours. The difference was significant (p < 0.001) and an increasing trend was established. Strong staining was seen in subepithelial areas with higher stromal cellularity and activity. Stromal CD10 expression had a high specificity (95%) for differentiating between benign lesions (fibroadenomas and benign phyllodes tumours) and malignant (borderline and frankly malignant) phyllodes tumours.

CONCLUSIONS

CD10 may be a useful adjunct in assessing malignancy in mammary fibroepithelial lesions.

Beta-amyloid catabolism: roles for neprilysin (NEP) and other metallopeptidases?

The steady-state level of amyloid beta-peptide (Abeta) represents a balance between its biosynthesis from the amyloid precursor protein (APP) through the action of the beta- and gamma-secretases and its catabolism by a variety of proteolytic enzymes. Recent attention has focused on members of the neprilysin (NEP) family of zinc metalloproteinases in amyloid metabolism. NEP itself degrades both Abeta(1-40) and Abeta(1-42) in vitro and in vivo, and this metabolism is prevented by NEP inhibitors. Other NEP family members, for example endothelin-converting enzyme, may contribute to amyloid catabolism and may also play a role in neuroprotection. Another metalloproteinase, insulysin (insulin-degrading enzyme) has also been advocated as an amyloid-degrading enzyme and may contribute more generally to metabolism of amyloid-forming peptides. Other candidate enzymes proposed include angiotensin-converting enzyme, some matrix metalloproteinases, plasmin and, indirectly, thimet oligopeptidase (endopeptidase-24.15). This review critically evaluates the evidence relating to proteinases implicated in amyloid catabolism. Therapeutic strategies aimed at promoting A,beta degradation may provide a novel approach to the therapy of Alzheimer's disease.

Malignant glioma biology: role for TGF-beta in growth, motility, angiogenesis, and immune escape

Characteristics of human malignant glioma are excessive proliferation, infiltrative growth, angiogenesis and suppression of anti-tumor immune surveillance. Transforming growth factor-beta (TGF-beta), a versatile cytokine, is intimately involved in the regulation of these processes. Here, we discuss the interactions of TGF-beta with growth factors, such as basic fibroblast growth factor (bFGF), epidermal growth factor (EGF) and platelet derived growth factor (PDGF), metalloproteinases (MMP-2, MMP-9) and their inhibitor, plasmin activator inhibitor-1 (PAI-1), and immune cells, like natural killer cells, T-cells and microglia. The differential effects of TGF-beta in glioma biology are outlined with emphasis on the induction of a survival advantage for glioma cells by enforced cell growth, migration, invasion, angiogenesis and immune paralysis. By virtue of its growth regulatory and immunomodulatory properties, TGF-beta promises to become a novel target for the experimental therapy of human malignant glioma.

Paraffin-section detection of CD10 in 505 nonhematopoietic neoplasms. Frequent expression in renal cell carcinoma and endometrial stromal sarcoma

We tested 505 cases of nonhematopoietic neoplasms by immunohistochemistry using a newly characterized monoclonal antibody (clone 56C6) against the CD10 antigen. CD10 was expressed widely in neoplasms of the genitourinary tract, including 41 (89%) of 46 cases of renal cell carcinoma, 13 (54%) of 24 cases of transitional cell carcinoma, and 11 (61%) of 18 cases of prostatic adenocarcinoma. In addition, 5 (100%) of 5 endometrial stromal sarcomas, 3 (60%) of 5 rhabdomyosarcomas, 7 (50%) of 14 pancreatic adenocarcinomas, 5 (45%) of 11 cases of schwannoma, and 12 (40%) of 30 cases of malignant melanoma also were positive for CD10. Similar to normal tissue, CD10 positivity was restricted to the apical surface of malignant glandular cells of well-differentiated colonic, pancreatic, and prostatic adenocarcinoma, whereas in poorly differentiated adenocarcinoma and other tumors, such as melanoma, transitional cell carcinoma, renal cell carcinoma, and endometrial stromal sarcoma, the CD10 positivity showed diffuse cytoplasmic or membranous/Golgi patterns. The monoclonal antibody clone 56C6 is a reliable marker for CD10 in paraffin immunohistochemistry after heat-induced epitope retrieval. CD10 expression in renal cell carcinoma and endometrial stromal sarcoma may be a useful marker in the differential diagnoses of these tumors because both tumors otherwise lack specific markers.

Expression of CD10/neutral endopeptidase in normal and malignant tissues of the human stomach and colon

The expression of common acute lymphoblastic leukemia antigen (CALLA; CD10), which is identical to neutral endopeptidase (NEP, EC3.424.11), was examined in the malignant and adjacent noninvaded tissues of the human stomach and colon (n = 27). All of 27 normal and 18 well or moderately differentiated adenocarcioma tissue specimens were positive for monoclonal antibody (mAb) NL-1 against CD10/NEP, whereas the expression level was clearly decreased in all of 9 specimens of poorly differentiated adenocarcinoma. In addition, all of 7 gastric or colorectal carcinoma cell lines tested showed decreased expression of CD10/NEP. Sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis of the crude antigen J5 from the normal colon tissue lysate by mAb J5 detected a single band of approximately 100 kDa that was consistent with that of NALM-6 cells used as a positive control. These findings suggest that CD10/NEP is expressed in normal epithelial cells of the human stomach and colon, whereas the expression level is decreased in the poorly differentiated type of adenocarcinoma.

The failure of current immunotherapy for malignant glioma. Tumor-derived TGF-beta, T-cell apoptosis, and the immune privilege of the brain

Human malignant gliomas are rather resistant to all current therapeutic approaches including surgery, radiotherapy and chemotherapy as well as antibody-guided or cellular immunotherapy. The immunotherapy of malignant glioma has attracted interest because of the immunosuppressed state of malignant glioma patients which resides mainly in the T-cell compartment. This T-cell suppression has been attributed to the release by the glioma cells of immunosuppressive factors like transforming growth factor-beta (TGF-beta) and prostaglandins. TGF-beta has multiple effects in the immune system, most of which are inhibitory. TGF-beta appears to control downstream elements of various cellular activation cascades and regulates the expression of genes that are essential for cell cycle progression and mitosis. Since TGF-beta-mediated growth arrest of T-cell lines results in their apoptosis in vitro, glioma-derived TGF-beta may prevent immune-mediated glioma cell elimination by inducing apoptosis of tumor-infiltrating lymphocytes in vivo. T-cell apoptosis in the brain may be augmented by the absence of professional antigen-presenting cells and of appropriate costimulating signals. Numerous in vitro studies predict that tumor-derived TGF-beta will incapacitate in vitro-expanded and locally administered lymphokine-activated killer cells (LAK-cells) or tumor-infiltrating lymphocytes. Thus, TGF-beta may be partly responsible for the failure of current adoptive cellular immunotherapy of malignant glioma. Recent experimental in vivo studies on non-glial tumors have corroborated that neutralization of tumor-derived TGF-beta activity may facilitate immune-mediated tumor rejection. Current efforts to improve the efficacy of immunotherapy for malignant glioma include various strategies to enhance the immunogenicity of glioma cells and the cytotoxic activity of immune effector cells, e.g., by cytokine gene transfer. Future strategies of cellular immunotherapy for malignant glioma will have to focus on rendering glioma cell-targeting immune cells resistent to local inactivation and apoptosis which may be induced by TGF-beta and other immunosuppressive molecules at the site of neoplastic growth. Cytotoxic effectors targeting Fas/APO-1, the receptor protein for perforin-independent cytotoxic T-cell killing, might be promising, since Fas/APO-1 is expressed by glioma cells but not by untransformed brain cells, and since Fas/APO-1-mediated killing in vitro is not inhibited by TGF-beta.

Growth inhibition of human glioma cells modulated by retrovirus gene transfection with antisense IL-8

The human glioma cell line, NP-1, expresses IL-8 mRNA and constitutively secretes IL-8 protein. Administration of recombinant IL-8 increased the proliferation of NP-1 cells in a dose-dependent manner. In the presence of anti-IL-8 antiserum, the IL-8 mediated proliferation of NP-1 cell growth was inhibited. Further, NP-1 cell growth was inhibited by transfection of retroviral constructs encoding antisense IL-8 both in vitro and in vivo models. These results suggest that antisense IL-8 gene therapy could be beneficial in gliomas where autocrine stimulation by IL-8 is implicated.

Expression of common acute lymphoblastic leukemia antigen (CD 10) by myelinated fibers of the peripheral nervous system

The common acute lymphoblastic leukemia antigen (CALLA), CD10, is a 100-kDa surface glycoprotein endowed with neutral endopeptidase activity, shared by a number of hemopoietic and non-hemopoietic cells. In this report, immunohistochemical and Western blot techniques, using different anti-CD10 monoclonal antibodies, were utilized to demonstrate that CD10 is also expressed by myelin sheaths of the human peripheral nervous system (PNS), but not of the central nervous system. CD10-positive immunoreactivity appeared to be localized in the outer and inner borders of myelinated fibers, in nodes of Ranvier and in the Schmidt-Lantermann clefts, thus showing a distribution pattern very similar to that of myelin-associated glycoprotein (MAG). The above findings suggest that CD10 antigen, through its enzymatic activity, may have a functional role in the assembly and maintenance of PNS myelin. In addition, it is not known whether CD10, similarly to MAG, may be a target antigen in some PNS immune-mediated disorders.

Induction of toxoplasmostasis in a human glioblastoma by interferon gamma

In the course of human toxoplasmosis central nervous system involvement often occurs. As a model for toxoplasma growth within human brain cells the proliferation of Toxoplasma gondii strain BK within the human glioblastoma cell line 86HG39 was analysed. We found that 86HG39 cells support the growth of toxoplasma similar to human monocyte derived macrophages and in contrast to human monocytes. The growth of Toxoplasma gondii within interferon gamma (IFN gamma) treated 86HG39 cells is reduced due to toxoplasmostasis and not due to toxoplasmocide effects. The mechanism of IFN gamma induced toxoplasmostasis was also investigated. It was found that IFN gamma did not induce O2- production and/or nitrite oxide production, and inhibitors of O2- and NO2- did not influence IFN gamma induced toxoplasmostasis. In contrast, the supplementation of L-tryptophan to the culture medium completely abolished the IFN gamma effect. We therefore conclude that the induction of L-tryptophan degradation in 86HG39 cells by IFN gamma, possibly by activation of the indoleamine-2,3-dioxygenase, is responsible for the IFN gamma induced toxoplasmostasis within the glioblastoma cell line.

Interleukin-1 and tumor necrosis factor-mediated regulation of C3 gene expression in human astroglioma cells

In this report, we show that in the human astroglioma cell line D54-MG, both interleukin-1 (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) enhance C3 gene expression in a time- and dose-dependent manner. Kinetic analysis demonstrates that after 96 h, C3 mRNA levels increase approximately 30-fold and 20-fold in response to IL-1 beta or TNF-alpha, respectively. C3 protein production increases proportionally, reaching levels 36-fold and 18-fold higher than untreated controls upon exposure to IL-1 beta or TNF-alpha, respectively. D54-MG cells require a minimal 1 h exposure to IL-1 beta in order to enhance C3 gene expression significantly, while 4 to 8 h are required for TNF-alpha. Simultaneous treatment of D54-MG cells with IL-1 beta and interferon-gamma (IFN-gamma) resulted in an additive increase in both C3 mRNA and protein expression, a finding not seen with the combination of TNF-alpha and IFN-gamma. Primary rat astrocytes also express increased C3 mRNA levels after 48 h in response to IL-1 beta (5.3-fold increase) and TNF-alpha (7-fold increase), while an additive effect was observed upon simultaneous treatment with both IL-1 beta and IFN-gamma. In the central nervous system (CNS), endogenous complement and cytokine production by astrocytes, and enhancement by IFN-gamma, a product of activated T cells often seen in the CNS in neural autoimmune disease, may contribute to the pathogenesis of inflammatory demyelinating diseases such as multiple sclerosis.

Differential expression of leukocyte differentiation antigens in small round blue cell sarcomas

BACKGROUND

Small round blue cell sarcomas (SRBCS) comprise a group of cytomorphologically poorly differentiated neoplasms that are characterized by different histogenesis and biologic behavior.

METHODS

Twenty-seven well-characterized SRBCS were examined immunohistochemically to detect the expression of a panel of leukocyte differentiation (CD) antigens and class I (HLA-A,B,C) and class II (HLA-DR) major histocompatibility complex antigen.

RESULTS

Although various cell surface antigens were detectable in SRBCS, the pan-leukocytic-histiocytic CD53 antigen was absent in the neoplastic population of all tumors studied; this finding allowed the authors to discriminate these lesions from lymphomas and leukemias. Some antigens had a differential pattern of expression in the SRBCS group, in particular in the undifferentiated tumor cell populations. In most instances, neuroblastomas (NB) and ganglioneuroblastomas (GNB) were CD9+/CD24+/CD56+ but CD40-/HLA-A,B,C-. Rhabdomyosarcomas (RMS) were CD56+ in all specimens and CD9+ in many samples; generally, they showed CD24-/CD40-/HLA-A,B,C-. Ewing sarcomas (ES) and peripheral primitive neuroectodermal tumors (pPNET) were HLA-A,B,C+/CD40+ but CD9-/CD24-/CD56- in most instances. Thus, with few exceptions, the expression of CD9 and CD56 and the simultaneous absence of HLA-A,B,C and CD40 differentiated GNB, NB, and RMS from ES and pPNET. GNB, NB, and RMS differed in regard to their CD24 expression.

CONCLUSIONS

These data show that various types of SRBCS have different patterns of cell surface antigens. Therefore, these antigens are considered to be helpful in the immunophenotypic subclassification of SRBCS: The immunophenotypic similarities between ES and pPNET, however, might be an additional argument for a close relationship between these two lesions.

Human glioblastoma cell line 86HG39 activates T cells in an antigen specific major histocompatibility complex class II-dependent manner

The capacity of three different human glioblastoma cell lines to activate human T cells was analysed by measuring major histocompatibility complex (MHC) antigen expression, monokine secretion and lectin, mAb OKT3 and antigen-driven T cell proliferation. All glioblastoma cells tested were able to induce PHA and concanavalin A (ConA)-driven T cell proliferation in a dose-dependent fashion, while all failed to induce T cell activation with mAb OKT3. In addition, the glioblastoma cell line 86HG39 was able to induce tetanus toxoid and toxoplasma lysate antigen-specific T cell proliferation. The responding T cell lines originated from only one out of five different donors. This foreign antigen-specific T cell proliferation induced by 86HG39 cells could be inhibited with mAb L243 directed against HLA-DR molecules. The study of monokine secretion by 86HG39 cells showed a strong interleukin (IL)-6 secretion after lipopolysaccharide (LPS) treatment, whilst no IL-1 secretion was observed. Furthermore, only 86HG39 cells were positive for HLA-DR molecules, whereas interferon (IFN) gamma treatment of 87HG28 and 87HG31 cells was necessary for the induction of class II antigen expression. Thus, cell line 86HG39 shows many features of an antigen presenting cell and the interaction of these cells with MHC compatible human T cells might be a useful model to study cellular immune reactions within the central nervous system.

Expression of cALLa/NEP on gliomas: a possible marker of malignancy

First described on pre-B leukemia cells, the common acute lymphoblastic leukemia antigen (cALLa) is also expressed on glioma cells in vitro. Its identity to neutral endopeptidase (NEP) (E.C.3.24.11) was corroborated by our finding that cALLa positive glioma cells had NEP activity. To study cALLa/NEP distribution on glial tumours in vivo, we examined 76 brain tumour biopsies by immunostaining techniques on frozen tissue sections using anti-cALLa (FAH99) and anti-NEP (135 A 3) monoclonal antibodies. We found that 96% of grade 4 gliomas (25/26) expressed NEP. Whereas only 45% (4/9) of grade 3 or anaplastic astrocytomas did. In low grade gliomas, we found 2 positive tumours out of 21 tested (10%). Double immunostaining procedures revealed that NEP was co-expressed with GFAP. However no NEP could be detected on non-glial brain tumours nor on reactive astrocytes. These results suggest that cALLa/NEP expression could be linked to malignant progression of gliomas.

Interleukin-1 beta induction of tumor necrosis factor-alpha gene expression in human astroglioma cells

Cells that produce tumor necrosis factor-alpha (TNF-alpha) require the presence of signaling molecules since this cytokine is not normally expressed in a constitutive manner. It has been demonstrated that glial cells can produce TNF-alpha; however, the specific inducing molecules and their mechanism(s) of action have not been clearly defined. In this study, we examined the effect of human recombinant interleukin-1 beta (IL-1 beta) on the expression of TNF-alpha by CH235-MG human malignant glioma cells. CH235-MG cells do not constitutively express TNF-alpha mRNA or protein; however, upon stimulation with IL-1 beta, these cells synthesize and secrete biologically active TNF-alpha. IL-1 beta induces the expression of a 1.9 kb TNF-alpha mRNA species. Kinetic analysis demonstrated optimum TNF-alpha mRNA expression after a 4 h exposure to IL-1 beta, and peak TNF-alpha protein production at 18 h. Cycloheximide (CHX), an inhibitor of protein synthesis, markedly increased expression of TNF-alpha mRNA in IL-1 beta stimulated CH235-MG cells, indicating that de novo protein synthesis is not required for astroglioma TNF-alpha gene expression. Nuclear run-off analysis demonstrates that IL-1 beta causes transcriptional activation of the TNF-alpha gene, and CHX enhances IL-1 beta-induced TNF-alpha transcription. Studies of TNF-alpha mRNA stability using actinomycin D show that IL-1 beta-induced TNF-alpha mRNA has a half-life of approximately 30 min, and CHX increases the half-life of IL-1 beta-induced TNF-alpha mRNA to approximately 210 min. These results indicate that IL-1 beta, a cytokine present in the central nervous system during some pathological disease states, is a potent inducer of TNF-alpha in human malignant glioma cells.

CD10 and CD44 genes of leukemic cells and malignant cell lines show no evidence of transformation-related alterations

The expression of CD10/CALLA is associated primarily with childhood leukemia of pre-B lymphocyte phenotype. We have compared the hybridization pattern of the CALLA gene from leukemic and normal cells digested with several restriction enzymes. No alterations were noticed with Eco RI, Sac I, Pvu II, Eco RV, Hind III, and Msp I. Since CALLA is also found on other malignancies, we analyzed DNA samples prepared from cell lines derived from leukemia, lymphoma, glioblastoma, retinoblastoma, and neuroblastoma. Normal restriction patterns were observed for all the lines regardless of their CALLA phenotype. Having demonstrated previously that CALLA was structurally identical to neutral endopeptidase 3.4.24.11 (NEP), we have now established a correlation between surface expression of CALLA and NEP activity on leukemia samples and on several cell lines. Malignant cells tested expressed a functionally active enzyme and no gross alteration was present in the CALLA gene. The CD44 gene is expressed on most cells of hemopoietic origin and on greater than 95% of cases of acute lymphoblastic leukemia and acute myeloblastic leukemia studied. It is also expressed on normal astrocytes and on malignant cells of glioma/astrocytoma types. We now report that a similar pattern of hybridization was observed with Sac I, Pvu II, and Eco RI for leukemic samples, normal cells, and malignant cell lines. A polymorphism was recently detected for CD44 using Hind III; leukemic cells and malignant lines also showed this normal polymorphism. Thus no deletion or insertion could be detected in the CD44 gene of leukemic cells and malignant lines, suggesting that no gross DNA alterations were involved. The correlation between surface expression and enzymatic activity of CD10/CALLA and the expression of CD44 on a variety of malignant cells would suggest that the structure and function of these two gene products are probably not altered by the process of transformation.

Mononuclear cell infiltrate and HLA-Dr expression in intra- and extradural secondary carcinomas

Frozen sections from 30 secondary carcinomas (22 intra- and 8 extradural) were reacted with a panel of monoclonal antibodies to macrophages, lymphocytes, NK cells and HLA-Dr invariant chain. A moderate number of macrophages was demonstrated in 91% of tumours. CD 8 and CD 4 lymphocytes were detected in smaller numbers in 68% and 28% of tumours respectively. B lymphocytes were present in only one tumour and NK cells were absent. There was no significant difference between the mononuclear cell infiltrate in the intra- and extradural tumours and in respect to the histological tumour type. HLA-Dr antigen was expressed by macrophages in most cases and by tumour cells in 5/22 (22%) (4 adeno and 1 anaplastic carcinoma; of which one adenocarcinoma was extradural and the remaining intradural). The results may represent evidence for a degree of cellular immune response to secondary carcinomas which is independent of the intra- or extradural location of the tumour.

Degradation of alpha-melanocyte stimulating hormone (alpha-MSH) by CALLA/endopeptidase 24.11 expressed by human melanoma cells in culture

The common acute lymphoblastic leukemia antigen (CALLA) is identical to human endopeptidase 24.11 (E-24.11) and is expressed on certain human melanoma lines. This work was conducted in order to investigate whether alpha-melanocyte-stimulating hormone (alpha-MSH) could be a substrate for E-24.11, its degradation leading to the negative alpha-MSH radiobinding assay results observed with some CALLA-positive cell lines. We used 3 human melanoma cell lines (GLL-19, Mel Juso and G361) which lack receptors to alpha-MSH and express CALLA, and, as a control, one CALLA-negative melanoma cell line (HBL) with specific receptors for alpha-MSH. Radioimmunoassays give evidence that alpha-MSH was degraded in the presence of the 4 melanoma cell lines and that disappearance of the peptide was significantly reduced by phosphoramidon in 2 lines (GLL-19 and G361). Upon incubation of alpha-MSH with GLL-19 and G361 cell membranes, 3 degradation products were completely abolished in the presence of phosphoramidon. Amino acid content analysis of alpha-MSH fragments produced by purified E-24.11 permitted identification of 6 peptide bonds in the sequence of alpha-MSH susceptible to cleavage by the enzyme. It is concluded that alpha-MSH is a substrate in vitro for purified E-24.11 and for the enzyme present on the human melanoma cell lines GLL-19 and G361, expressing a high level of endopeptidase activity. However, hydrolysis of alpha-MSH by this enzyme does not seem to represent the main factor responsible for the apparent absence of receptors for the hormone on some cell lines.

Tumor necrosis factor production and receptor expression by a human malignant glioma cell line, D54-MG

Human malignant gliomas possess some of the same immune-related functions as astrocytes do. For instance, they are capable of secreting various immunoregulatory molecules and expressing HLA-DR antigens on their surface. The human malignant glioma cell line, D54-MG, was used to investigate the proliferative effects of tumor necrosis factor-alpha (TNF-alpha) and the expression of specific surface receptors for TNF-alpha. Additionally, we were interested in examining whether D54-MG cells are capable of synthesizing and secreting biologically active TNF-alpha. D54-MG cells responded in a mitogenic fashion upon incubation with TNF-alpha for 48 h under serum-free conditions. 125I-labeled TNF-alpha was used in this study to investigate the expression of receptors specific for TNF-alpha on D54-MG cells. Scatchard analysis of our receptor binding data produced curvilinear plots indicating there are two distinct receptor sites for TNF-alpha. From these data, we calculated that there are approximately 3500 high affinity and 24,666 low affinity binding sites per cell. Pretreating these cells with interferon-gamma (IFN-gamma) resulted in a 2-fold increase in the number of high affinity binding sites and a moderate increase in the number of low affinity binding sites, with no appreciable change in binding affinity (Kd) of either site. D54-MG cells were unable to constitutively secrete TNF-alpha; however, upon stimulation, these cells synthesize and secrete biologically active TNF-alpha. Polyclonal antisera reactive with human macrophage-derived TNF-alpha neutralized the cytotoxicity of D54-MG-derived TNF-alpha, demonstrating that the cytotoxic activity was in fact due to TNF-alpha. Our observations indicate that TNF-alpha could act in an autocrine fashion to induce the proliferation of this malignant glioma cell line and that TNF-alpha exerts its effect by binding to specific TNF-alpha receptors whose expression was enhanced by IFN-gamma.

Neurotensin high affinity binding sites and endopeptidase 24.11 are present respectively in the meningothelial and in the fibroblastic components of human meningiomas

The presence of neurotensin receptors and endopeptidase 24.11 (E-24.11) in 16 human meningioma specimens, obtained at surgery, was assessed by measuring the binding of 125I-[tyrosyl3]neurotensin(1-13) (125I-NT) and the inhibitor 3H-N(2RS)-3-hydroxyaminocarbonyl-2-benzyl-1-oxopropyl)glycine (3H-HACBO-Gly), for the receptor and enzyme, respectively. E-24.11 activity was also measured. Autoradiography, on the 16 meningiomas, showed that specific 125I-NT labeling (nonspecific labeling was assessed in the presence of excess NT) was exclusively located in the meningothelial regions. In contrast, specific 3H-HACBO-Gly labeling (nonspecific labeling was assessed in the presence of an excess of the E-24.11 inhibitor thiorphan) was exclusively found in fibroblastic regions. No specific labeling of either ligand was found on collagen or blood vessels. In vitro binding assays were performed on membranes of 10 of the 16 meningiomas. In the 4 meningiomas rich in meningothelial cells, 125I-NT specifically bound to one population of sites with Bmax ranging from 57 to 405 fmol/mg protein and Kd around 0.3 nM. These sites share common properties with the brain NT receptor, since the carboxy terminal acetyl NT(8-13) fragment bound to the same sites but with a higher affinity. The carboxy terminal analogue of NT, neuromedin N, also bound to the same sites with a 10-fold lower affinity and the sites were bradykinin and levocabastine insensitive. In the 4 meningiomas rich in fibroblastic cells, 3H-HACBO-Gly specifically bound to one population of sites with Bmax ranging from 251 to 739 fmol/mg protein and Kd around 2.8 nM.(ABSTRACT TRUNCATED AT 250 WORDS)

Localisation of CD10 to biliary canaliculi by immunoelectron microscopical examination

Common acute lymphoblastic leukaemia antigen (CALLA) was first characterised in lymphoid leukaemic cells. The antigen is present in different stages of lymphoid cell differentiation as well as in subsets of myeloid cells, and further studies have also shown its presence in non-lymphoid tissues. The recent cloning and sequencing of the gene permitted deduction of its amino acid sequence which is identical with the human membrane-associated enzyme, neutral endopeptidase. Strong immunostaining for CALLA was detected in the human liver with a canalicular pattern. Immunoelectron microscopy also confirmed that the antigen was localised only in the area of the bile canaliculi. Although the function of neutral endopeptidase in the canaliculi is unknown, this antigen may prove useful in the study of biliary function and diseases.

Monocyte subpopulations in human gliomas: expression of Fc and complement receptors and correlation with tumor proliferation

Cryostat sections of 12 gliomas and of 3 peritumoral brain tissue samples were investigated for mononuclear cell infiltration by immunohistochemistry, concentrating on cells expressing monocyte/macrophage markers. Only low numbers of T cells were detected in the tumors, whereas in average 20%-30% of all cells present in the samples were recognized by various macrophage markers. These cells carried surface epitopes with known function, like Fc-gamma (Fcg) and complement receptors. Microglial cells, in comparison to typical debris laden macrophages, were only recognized by a restricted panel of macrophages markers (anti-Fcg receptors 1, 2, 3, complement receptor CR3, HLA DR, common leucocyte antigen CD45 and the monocyte marker RM3/1). In peritumoral tissue mainly dendritic, microglia-like cells were present, which revealed decreased expression of antigens CD4, RM3/1 and Fcg receptors in comparison to those in gliomas. A significant positive correlation was found between the number of RM3/1 or CR3 (CD11b)-positive cells and the proliferation rate of the tumors as documented by the number of bromodeoxyuridine-positive or Ki-67+ cells.

Production and characterization of a human monoclonal antibody recognizing a new antigen expressed on some lymphoid cells

A cell line secreting a human monoclonal antibody was established by Epstein-Barr virus transforming B cells derived from an enlarged cervical lymph node excised from a patient bearing a carotid body tumor. The reactivity of the monoclonal antibody, designated as mNISP, was tested on various cells and cell lines. An antigen defined by the mNISP was expressed on some Burkitt's lymphoma cell lines and on a non-T non-B acute lymphoblastic leukemia cell line. Furthermore, this antigen was expressed on leukemic cells from 2 of 8 patients with chronic myelocytic leukemia, 2 of 10 patients with acute myeloblastic leukemia, one of 13 patients with acute lymphoblastic leukemia, and two patients with adult T cell leukemia, but it was not expressed on normal T, B and adherent (macrophage) cells. In addition, mNISP reacted with T cells obtained from human T-cell leukemia virus type I carriers. We found that the antigen defined by mNISP was distinct from any previously reported antigen in terms of its pattern of cellular expression and molecular weight, suggesting that mNISP recognizes a new antigen expressed on some lymphoid cells.

Cross-reactivity of monoclonal antibody Leu-19 with some neuroectodermal and other non-immune tissues

Leu-19 antigen is a 200-220 kDa surface glycoprotein, initially detected on natural killer (NK) cells exhibiting non-major histocompatibility complex-restricted cytotoxicity. Using a monoclonal antibody (mAb) directed against the Leu-19 molecule, we were unable to identify NK cells immunohistologically in cryostat sections of neuroectodermal tumors. Instead, mAb Leu-19 cross-reacted with the surfaces of the tumor cells, except for melanomas. It stained mesodermal tumor cells less intensely and did not stain those of carcinoma metastases. In three plasmacytomas, cells were observed, most likely NK cells, which extend Leu-19-positive cell processes towards to the unstained tumor cells. Furthermore, the Leu-19 antigen was identified on physiological tissues, especially on all neuroendocrine cells analyzed. The cross-reactions observed with Leu-19 mAb were confirmed using mAb NKH-1, which is also directed against the Leu-19 molecule. Thus, the expression of Leu-19 on neuroectodermal cells is another example of antigen sharing between specialized immune cells and the nervous system.

Immunobiology of brain tumors

In summary, many actual interactions between tumors in the CNS and the immune system have been demonstrated. The normal brain does not possess a lymphatic system and is partially hidden from the systemic immune system by the BBB, furthermore brain cells do not express MHC antigens which are necessary for the initiation of an immune response. In pathological conditions however, immunocompetent cells may find their way through transformed endothelial cells. Microglia and astrocytes may function as antigen presenting cells. Glioma cells when stimulated by cytokines such as IFN gamma can be induced to express MHC class I and class II antigens, thus making them more susceptible to an immune attack. In addition glioma cells are capable of secreting several cytokines including IL 1, IL 3 and IL 6 also involved in the generation of an immune response. Indeed, a functional analysis of lymphocytes infiltrating gliomas has revealed the accumulation at the tumor site of cytotoxic T lymphocytes as well as NK cells. However host-immune responses against gliomas seem to be weak in comparison to other cancers. Glioma cells are known to secrete TGF beta 2 and PGE 2 which may in part be responsible for this lack of immune response, thus shielding themselves from immune attack. In order to be recognized by the immune system the tumor cells must express TAA in addition to MHC antigens, and such TAA have been identified by MAbs. These MAbs can be used for "targeted" therapy when coupled to toxic agents or radionuclides. Preclinical studies have shown that, after intravenous or intracarotid injection, there is specific accumulation of the MAb in the tumor but in insufficient amounts for therapeutic use. The relatively small amount of MAb binding to the tumor in vivo can be due to several factors: not all the cells in a single tumor express a given tumor-associated antigens, the MAb may have a low affinity for the antigen, the BBB may hinder the passage of the MAb. Attempts have been made to overcome these drawbacks by opening the BBB for example. In addition MAbs can readily be used for the treatment of carcinomatous meningitis. There has been little success in the development of immunotherapy with IFN beta 1 and even less with adoptive immunotherapy using LAK cells plus IL 2. TIL as well as LAK cells can be expanded in vitro with IL2 and it is feasible to reinject these cells into the tumor site.(ABSTRACT TRUNCATED AT 400 WORDS)

Ability of human colonic epithelium to express the 4F2 antigen, the common acute lymphoblastic leukemia antigen, and the transferrin receptor. Studies in inflammatory bowel disease and after in vitro exposure to different stimuli

We investigated the ability of isolated human colonic epithelial cells to express the common acute lymphoblastic leukemia antigen (CALLA), the transferrin receptor, and the 4F2 antigen in response to different types of stimuli. The expression of these markers was assessed by immunofluorescence using monoclonal antibodies. Thirty-two percent of freshly isolated colonic epithelial cells from actively inflamed mucosa of patients with inflammatory bowel disease expressed the 4F2 antigen, 28% the transferrin receptor, and 13% the CALLA. Normal colonic epithelial cells were cultured and the kinetics of expression of the three antigens was studied. A significant increase in the expression of the three markers was observed throughout the culture period in response to the lectin phytohemagglutinin and the epidermal growth factor. The kinetics of expression of the 4F2 antigen and the CALLA after lectin stimulation appeared to differ from that observed after epidermal growth factor. At the end of the cultures one-third of the cells expressed the 4F2 antigen and the transferrin receptor, whereas one-fifth were positive for CALLA. Thus, after these cultures the expression of the three markers was quantitatively similar to that observed with freshly isolated cells from inflamed mucosa. gamma-Interferon markedly induced the 4F2 antigen but had no effect on the transferrin receptor and the CALLA. These data demonstrate that colonic epithelium is capable of expressing the 4F2 antigen and the CALLA in association with the transferrin receptor.

Immunology of central nervous system tumors

With progress in cellular immunology and the development of hybridoma technology, the idea of manipulating host-tumor immune interactions to improve the prognosis of brain tumors has aroused renewed interest. Although no brain tumor-specific antigens have been found, and in spite of the wide antigenic heterogeneity of brain tumor cells, some monoclonal antibodies possessing restricted specificity have been isolated and their potential clinical applications investigated. One of the most pronounced changes in the cellular immune responses of brain tumor patients is a profound depression of the T4-helper lymphocytes. Clinical and laboratory trials are under way to assess the ability of lymphokines, such as gamma-interferon or interleukin-2, to restore immunologic competence in these patients and potentiate a specific anti-tumor immunologic response. Recent work suggests that the endothelium-astrocyte complex may have a pivotal role in assisting the escape of brain tumors from the host's immunologic responses, since it is responsible for the intracerebral sequestration of antigens and local anti-tumor responses. In this review, the data on the antigenic properties of central nervous system tumors and the host's humoral and cellular immune responses to them are analyzed and potential immunologic therapies are discussed.

Human glioma cell lines expressing the common acute lymphoblastic leukemia antigen (cALLa) have neutral endopeptidase activity

Several established human glioma cell lines have been previously shown to express the common acute lymphoblastic leukemia antigen (cALLa, CD 10), an important marker in the diagnosis of human acute lymphocytic leukemia (ALL). The amino acid sequence of cALLa is identical to that of neutral endopeptidase (NEP,E.C.3.4.24.11), and cALLa expressed on leukemia and melanoma cell lines is enzymatically active NEP. In the present study, we investigated whether cALLa expressed on glioma cell lines is active NEP. We detected cALLa on 10 out of 13 glioma cell lines using 2 different anti-cALLa MAbs (A12-G4 and FAH99). NEP antigen, as detected by immunostaining with an anti-NEP MAb (135A3), was expressed on the same 10 lines. cALLa-positive, but not cALLa-negative cell lines displayed an endopeptidase activity. This activity could be blocked by phosphoramidon, a specific inhibitor of NEP. Furthermore, mRNAs hybridizing to an NEP-specific probe were present in cALLa-positive glioma cells but not in cALLa-negative cells. Taken together, the results provide strong evidence that cALLa-positive glioma cell lines express endopeptidase activity on the cell surface.

Immunophenotypic differences between normal glia, astrocytomas and malignant gliomas: correlations with karyotype, natural history and survival

The karyotypic and antigenic phenotypes of early passage normal and malignant glial cultures were correlated in vitro. Astrocytomas (4) were distinguished from the normal glia (8) by a mixed near-diploid karyotype and anchorage-independent growth. Malignant gliomas (41) demonstrated cytogenetic abnormalities ranging from mixed normal G- and Q-banded and near-diploid cultures, through mixed near-diploid/hyperdiploid to predominantly hyperdiploid stem-lines. This correlated with the differential expression of certain antigens and established qualitative antigenic differences from normal glia. Associations were found between histopathologic grade of glial neoplasm and the expression of antigens 5.1H11 (p = 0.0002), CNT/11 (p = 0.001), CNT/10 (p = 0.004), CAT301 (p = 0.014), M111 (p = 0.024), and L101 (p = 0.044). An ominous association was demonstrated between the duration of clinical survival and the expression of antigens 5.1H11 (p = 0.0007), CNT/10 (p = 0.027) and B2.6 (p = 0.038). Correcting for diagnosis and age, multivariate analysis demonstrated that HLA-DR (p = 0.050) and 5.1H11 (p = 0.069) were unfavorably correlated with patient survival. This suggests the application of the in vitro immunophenotype for its predictive utility, as well as a novel method of selection of tumor-associated antigens for monoclonal antibody-mediated immunotherapy.

The common acute lymphoblastic leukemia antigen (neutral endopeptidase-3.4.24.11) gene is located on human chromosome 3

We have previously isolated a cDNA clone encoding the common acute lymphoblastic leukemia antigen (CALLA) from a normal human kidney library. Analysis of the amino acid sequence deduced from nucleotide sequencing of this cDNA established that CALLA is identical to the recently cloned human neutral endopeptidase (NEP; E.C. 3.4.24.11). Southern blot analysis of SacI fragments of DNA from human-rodent somatic cell hybrids using a 1.6-kb CALLA cDNA probe showed that the CALLA-NEP gene is located on human chromosome 3.

Interferon-beta impairs induction of HLA-DR antigen expression in cultured adult human astrocytes

We studied the effect of interferons on the expression of class II histocompatibility (HLA-DR) antigens by cultured adult human astrocytes. Cultures were derived from brain tissue resected for surgical treatment of intractable epilepsy. Cultured astrocytes did not spontaneously display HLA-DR antigen as determined by immunocytochemistry and flow cytometry with antibody to HLA-DR. Astrocytes cultured for 72 h with recombinant or natural interferon-gamma (IFN gamma) demonstrated a dose-dependent increase in HLA-DR expression with optimal stimulation by 100 U/ml IFN gamma. HLA-DR expression was not detectable in astrocytes cultured with IFN gamma for less then 48 h, and peak HLA-DR expression (over 80% of cells) was seen at 120 h of culture. Optimal HLA-DR expression required continuous presence of IFN gamma. Exposure of astrocytes to recombinant or natural interferon-beta (IFN beta) did not induce HLA-DR and pretreatment of astrocytes with IFN beta or interferon-alpha (IFN alpha) significantly inhibited subsequent induction of HLA-DR expression by IFN gamma. These observations suggest that interferons may function in regulating human astrocyte HLA-DR expression within the central nervous system.

Neutral endopeptidase 24.11 and angiotensin converting enzyme like activity in CALLA positive and CALLA negative lymphoid cells

Taking advantage of the recently demonstrated identity of common acute lymphoblastic leukemia antigen (CALLA) and neutral endopeptidase EC.24.11 (NEP) the presence of this ectoenzyme on lymphoid cells has been reassessed using highly sensitive assays (cleavage of [3H]-D-Ala2-leucine-enkephalin and binding of the inhibitor [3H]HACBO-Gly. NEP activity was found not only on already classified CALLA + ve cells but also on numerous cells (including mature B and polyclonal T cells) previously considered as CALLA-ve. This suggests that CALLA/NEP is expressed all along the differentiation pathway in B and T cell lineage. Moreover substantial ACE-like activity was also detected in three tested cells, all of the pre-B phenotype. The availability of specific inhibitors for these enzymes should help clarify their role in cell-differentiation.

Immunology of gliomas

The treatment of cerebral gliomas continues to challenge neurosurgeons and research scientists. The lack of major success with chemotherapy and radiation therapy has given rise to further investigation into the biology of these tumors and host reactions to them. Much of this research has centered upon the evaluation of tumor cell antigenicity and on both the humoral and cellular immune responses to gliomas. Contrary to previous considerations, evidence suggests that astrocytes, glioma cells, and tumor endothelial cells may all have pivotal roles in the initiation and prolongation of both local and systemic immune responses to the tumor. In this review we will discuss the immunobiology of the glioma with specific reference to the interactions between the tumor and the host immune system. In addition, ideas for potential therapeutic manipulation of the host-glioma immune interactions will be reviewed, stressing potential pitfalls and risks.

Expression of the common acute lymphoblastic leukaemia antigen (CALLA) in the human breast

A biochemical and immunohistological study has been carried out to characterize the antigen in human breast reacting with antibodies to the common acute lymphoblastic leukaemia antigen (CALLA). Four different monoclonal antibodies to the CALLA antigen all stain the membrane of adult human myoepithelial cells. Surface labelling studies of freshly prepared human breast cells demonstrate that the anti-CALLA antibody, J5, immunoprecipitates a 100 kDa protein that co-electrophoreses with the CALLA antigen identified in the leukaemia cell line NALM-6. These results indicate that the CALLA antigen is expressed on myoepithelial cells and that the staining is not due to reactivity with a shared epitope on an unrelated molecule.

Common acute lymphoblastic leukemia antigen expressed on leukemia and melanoma cell lines has neutral endopeptidase activity

We have previously reported that the amino acid sequence of the common acute lymphoblastic leukemia antigen (CALLA, CD10) translated from a normal human kidney cDNA clone is identical to that of neutral endopeptidase (NEP, EC 3.4.24.11). In this study, we show that by flow cytometry, a monoclonal antibody (135A3) produced against rabbit NEP reacted selectively with leukemia and melanoma cell lines expressing CALLA on their surface. A glycoprotein of apparent Mr 100,000 was immunoprecipitated from surface labeled NALM-1 leukemia or Mel-1477 melanoma cells with monoclonal antibodies to NEP (135A3) or CALLA (44C10). mRNAs hybridizing to a NEP-specific probe were present in CALLA+ leukemia and melanoma cell lines, but absent from CALLA- lines. NEP enzymatic activity was detected on intact cells from CALLA+ lines, but not CALLA- lines. The activity was blocked by two selective inhibitors of NEP, thiorphan and phosphoramidon. CALLA antigen purified from the NALM-6 leukemic cell line by affinity to 44C10-IgG Sepharose retained a peptidase activity that was completely blocked by thiorphan and phosphoramidon. Thus the CALLA antigen present at the surface of leukemia and melanoma cell lines is an enzymatically active neutral endopeptidase.

Antigenic phenotypes of cultured malignant astrocytomas: identification of lineage-consistent, lineage-independent and putative tumor-restricted antigenic expression

The treatment of CNS neoplasms with monoclonal antibody-mediated immunotherapy optimally requires the identification of tumor restricted cell surface antigens. However, little is known regarding the antigenic phenotype(s) of malignant astrocytomas. The interrelated expression of four neuroectodermal tumor antigens, CNT/11, AJ8, A010 and CNT/2, has been studied in cultured malignant gliomas and correlated with anchorage independent growth, morphology, glial fibrillary acidic protein, and the surface expression of other antigens. Many of these latter antigens have been reported to be expressed by specific fetal and differentiated adult cell lineages or tissues, as well as certain classes of malignant tumors. The tumor-associated expression of these antigens may be broadly classified as lineage-consistent, lineage-independent or putatively tumor-restricted. Malignant glioma tumor antigenic heterogeneity represents the expression of neuroectodermal and non-neuroectodermal cell surface markers. The importance of this observation is 2-fold. Lineage-independent antigen expression may be an indication of altered genome regulatory processes within tumor cells, and thus reflect the degree of anaplasia. The identification of lineage-consistent and lineage-independent tumor associated antigens may contribute to the selection of "target" antigens and the prediction of toxicity for monoclonal antibody mediated immunotherapy.

Common acute lymphocytic leukemia antigen is identical to neutral endopeptidase

We purified CALLA from human kidney and isolated a cDNA clone reactive with two oligonucleotide probes corresponding to two distinct peptides. The amino acid sequence translated from the CALLA cDNA revealed 100% identity with that of human neutral endopeptidase (NEP, enkephalinase). The distribution of CALLA antigen and NEP in normal tissues are similar.

Sensitivity of human glioma cells to cytotoxic heteroconjugates

Several anti-human glioma cytotoxic conjugates were studied in vitro. Monoclonal antibodies (MAbs) to the GE2 glioma-associated antigen (anti-GE 2) and MAbs to HLA-DR antigens (D1/12) or human diferric transferrin (Tfn) were linked to the potent cytotoxin ricin (anti-GE 2-ricin) or to its A subunit (anti-GE 2-RTA, D1/12-RTA, Tfn-RTA). Anti-GE 2-RTA had low cytotoxic activity in both the absence and the presence of lysosomotropic substances inhibiting intracellular degradation. Anti-GE 2-ricin was about 1,000 times more toxic than RTA alone, but showed only 14-fold target specificity. D1/12-RTA was about 20 times more toxic than RTA and its cytotoxic effect increased about 6- to 7-fold when cell-surface HLA-DR antigen expression was enhanced by IFN-gamma treatment. Human diferric Tfn linked to RTA demonstrated the highest cytotoxic activity, being about 5,000 times more toxic than RTA alone for glioma cells and about 6,000 times more toxic for Jurkat cells in the presence of the carboxylic ionofore monensin. Ricin toxin was only about 5 times more toxic for Jurkat and glioma cells than Tfn-RTA-monensin. Tfn-RTA was over 100,000 times more potent than the chemotherapeutic agent BCNU in reducing glioma cell survival in vitro. Addition of 80% human pooled cerebrospinal fluid (CSF) reduced Tfn-RTA toxicity about 10-fold. Kinetics of Tfn-RTA cytotoxicity at non-saturating concentrations indicated that over 80% of target cells could be killed within 8-10 hr in the absence and within 10-12 hr in the presence of human pooled CSF.

Establishment and Characterization of a New Human Melanoma Cell Line (HU 214) with a High Growth Potential and Stable Properties

A human melanoma cell line (HU 214) with high growth potential was established from a lymph node metastasis of a patient with advanced cutaneous melanoma. The cells of this line were able to grow in monolayer (according to the Rosenblum technique) and in agar (according to the Courtenay-Mills method), and formed tumors when injected in nude mice. The line has been maintained in culture for more than 47 passages. The cell cultures were periodically characterized (every 6-8 passages) by immunohistochemistry using a panel of monoclonal antibodies (MoAbs) including MoAbs against tumor-associated antigens (antimelanoma, antiglioma and anti-LLA), against vimentin, and against major histocompatibility antigens, and including also Ki 67, a MoAb which reacts with a nuclear antigen associated with cell proliferation. The results of this characterization indicate that we have established a human melanoma cell line with a stable antigenic phenotype during subculturing, poorly differentiated cells, and a high growth potential.

An adoptive immunotherapy of patients with medulloblastoma by lymphokine-activated killer cells (LAK)

An adoptive immunotherapy of 6 patients with medulloblastoma by lymphokine-activated killer (LAK) cells is described. They were from 2 to 9 years in age and had cerebrospinal fluid (CSF) dissemination of the tumours. All patients underwent the whole-neuraxis irradiation and chemotherapy. After the usual treatments, they were submitted to an adoptive transfer of one-haplotype identical LAK cells. The LAK cells were induced from peripheral blood lymphocytes (PBL) of their relatives with human recombinant interleukin-2 (rIL-2). 3 - 15 x 10(9) LAK cells were transferred intrathecally in 2-3 months. In 3 of 6 patients, neurological signs were improved and malignant cells had never been detected on CSF cytology after the adoptive immunotherapy. One among these 3 patients showed complete response in 20 months. Thus, this is an attractive approach for the treatment of medulloblastoma with CSF dissemination of the tumour which current therapeutic intervention can not cure.