Growth stimulation of human head and neck squamous cell carcinoma cell lines by interleukin 4

Interleukin 4 (IL-4) has been reported recently to inhibit growth of acute lymphoblastic lymphoma, non-Hodgkin's lymphoma, melanoma, sarcoma, breast, gastric, colon, and renal tumor cell lines, and treatment of murine tumors with IL-4 gene-transduced cells has been therapeutically successful. Therefore, we sought to determine the effect of IL-4 on the growth of human squamous cell carcinoma of the head and neck (SCCHN) cell lines. Growth of SCCHN cell lines incubated in the presence of various concentrations of IL-4 was measured in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide colorimetric assays and by cell counts. Specific binding of IL-4 to SCCHN cells was demonstrated by flow cytometry with phycoerythrin-labeled IL-4, blocking studies with antibodies to IL-4, and using the radiolabeled ligand 125I-labeled IL-4. Reverse transcription PCR for IL-4 and IL-4 receptor (IL-4R) mRNA was performed. SCCHN tissue biopsies were examined by immunohistology and in situ hybridization for the presence of IL-4 protein and IL-4 mRNA in the tumor, respectively. In contrast to earlier reports, we observed growth stimulatory effects of IL-4 consistently in 6 of 13 SCCHN cell lines tested. Growth stimulation by IL-4 ranged from 20 to 200% of control (P < 0.05) and was IL-4 dose dependent. The growth-promoting effect of IL-4 was inhibited completely by incubation of tumor cells in the presence of antibodies specific for IL-4. Reverse transcription PCR analysis of mRNA obtained from the SCCHN cell lines and ELISA performed with SCCHN cell supernatants respectively indicated that the tumor cells did not transcribe or secrete IL-4 actively. The SCCHN cell lines expressed 260-540 IL-4Rs/cell with a dissociation constant of 100 +/- 8 pM. SCCHN cell lines also contained IL-4R mRNA. Immunostaining of SCCHN tissue biopsies indicated that IL-4 may be produced and secreted within these tumors by tumor-infiltrating lymphocytes. In situ hybridization for IL-4 mRNA indicated the presence of positive cells in the tumor stroma. Our data suggest that IL-4 may regulate the growth of SCCHN cells by a paracrine mechanism. These data also indicate that immunotherapy with exogenous IL-4 or IL-4 gene therapy to treat head and neck cancer may not be effective, given the potential tumor growth-stimulatory effects of this cytokine.

Constitutive production of IL-2 by human carcinoma cells, expression of IL-2 receptor, and tumor cell growth

Human carcinomas spontaneously express abundant IL-2R beta but little IL-2R alpha on the cell surface, contain mRNA for IL-2R beta- and IL-2R alpha-chains, and may be inhibited in growth by exogenous IL-2. To study the relationship between IL-2R expression and growth inhibition by IL-2, carcinoma cells were transduced with IL-2R alpha and IL-2R gamma cDNAs or IL-2R beta antisense cDNA. Transfectants with the IL-2R alpha gene expressed high levels of the alpha- and beta-receptor chains and showed increased binding of [125I]IL-2. Exogenous IL-2 at the picometer concentrations inhibited their growth, and Abs to IL-2R alpha- or IL-2R beta-chains reversed the inhibition. After transduction of IL-2R beta antisense cDNA, gastric carcinoma (HR) cells no longer expressed IL-2R beta-chain, and their proliferation was depressed in the absence of exogenous IL-2. Transduction of IL-2R gamma-chain cDNA into tumor cells increased sensitivity to growth inhibition by exogenous IL-2 of a squamous cell carcinoma line, but not of HR or renal cell carcinoma lines. All of the parental and transduced tumor cell lines were found to constitutively express intracellular IL-2, detectable by immunostaining or flow cytometry of permeabilized cells. IL-2 was present on the surface of some tumor cells. Intracellular IL-2R beta and IL-2R gamma proteins were also detectable in tumor cells. Using reverse-transcription PCR combined with Southern blots or in situ hybridization, mRNA for IL-2 was found to be present in parental and transduced tumor cells. Expression on human carcinomas of IL-2R beta, inhibition of their growth by IL-2R beta antisense cDNA, and their ability to constitutively produce IL-2 and its presence on the cell surface, all suggest that endogenous IL-2 may play a role in tumor cell growth.

Constitutive production of IL-2 by human carcinoma cells, expression of IL-2 receptor, and tumor cell growth

Human carcinomas spontaneously express abundant IL-2R beta but little IL-2R alpha on the cell surface, contain mRNA for IL-2R beta- and IL-2R alpha-chains, and may be inhibited in growth by exogenous IL-2. To study the relationship between IL-2R expression and growth inhibition by IL-2, carcinoma cells were transduced with IL-2R alpha and IL-2R gamma cDNAs or IL-2R beta antisense cDNA. Transfectants with the IL-2R alpha gene expressed high levels of the alpha- and beta-receptor chains and showed increased binding of [125I]IL-2. Exogenous IL-2 at the picometer concentrations inhibited their growth, and Abs to IL-2R alpha- or IL-2R beta-chains reversed the inhibition. After transduction of IL-2R beta antisense cDNA, gastric carcinoma (HR) cells no longer expressed IL-2R beta-chain, and their proliferation was depressed in the absence of exogenous IL-2. Transduction of IL-2R gamma-chain cDNA into tumor cells increased sensitivity to growth inhibition by exogenous IL-2 of a squamous cell carcinoma line, but not of HR or renal cell carcinoma lines. All of the parental and transduced tumor cell lines were found to constitutively express intracellular IL-2, detectable by immunostaining or flow cytometry of permeabilized cells. IL-2 was present on the surface of some tumor cells. Intracellular IL-2R beta and IL-2R gamma proteins were also detectable in tumor cells. Using reverse-transcription PCR combined with Southern blots or in situ hybridization, mRNA for IL-2 was found to be present in parental and transduced tumor cells. Expression on human carcinomas of IL-2R beta, inhibition of their growth by IL-2R beta antisense cDNA, and their ability to constitutively produce IL-2 and its presence on the cell surface, all suggest that endogenous IL-2 may play a role in tumor cell growth.

The role of natural killer cells in immune surveillance of cancer

In the past year, a subset of natural killer cells designated 'A-NK cells' has been characterized. These immune cells appear to be able to enter solid tissues, migrate to sites of metastasis and eliminate malignant tissue cells, but spare normal tissue cells. They appear to be ideal surveillance cells, readily capable of upregulating antitumor functions in response to local activation signals.

The role of natural killer cells in the treatment of chronic myeloid leukemia

The success of chemotherapy in patients with leukemia whose marrow appears to be replaced by leukemia cells must be due to the persistence of normal stem cells. In this normal population are the progenitors of the cells of the immune system. Natural killer (NK) cells originate in the bone marrow. On maturation and activation with interleukin 2 (IL-2) or other cytokines, NK cells develop cytotoxic activity against a variety of leukemic blasts, including those from patients with chronic myeloid leukemia (CML). In the past few years, bone marrow transplantation (BMT) and alpha-interferon (IFN-alpha) have proved to be the most promising therapies for the treatment of CML. In both these therapies, NK cells may play a prominent role. In this article, we discuss the antitumor/antileukemia activity of human NK cells, the presence of benign NK cell precursors in the different stages of CML, the role of NK cells in BMT and IFN-alpha treatment, and the potential therapeutic applications of NK cells in patients with hematologic malignancies.

Cytokines, immunoglobulins, and bacterial pathogens in middle ear effusions

OBJECTIVE

To elucidate the role of cytokines, immunoglobulins, and bacterial pathogens in the middle ear effusions (MEEs) of children with otitis media (OM).

DESIGN

Paired MEEs and serum samples collected from consecutive patients were assayed for immunoglobulins. Middle ear effusions were cultured for bacterial pathogens and assayed for interleukin-1 beta, interleukin-6, tumor necrosis factor alpha, and interferon gamma. The medical charts of the patients were retrospectively reviewed to define the history of OM.

SUBJECTS

Seventy-five patients with a history of recurrent acute OM, persistent OM with effusion, or both. Exclusion criteria included the presence of a major coexisting condition, or an unclear or atypical history of OM.

SETTING

A private practice at a tertiary care children's hospital.

INTERVENTIONS

At the time of tympanostomy tube placement, with the patient under general anesthesia, one MEE and a serum sample were collected.

RESULTS

Interleukin-1 beta was detected in 58% (44/75) MEEs; interleukin-6, 83% (60/72); tumor necrosis factor alpha, 37% (28/75) [corrected]; and interferon gamma, 61% (45/74). Concentrations of interleukin-1 beta, interleukin-6 and tumor necrosis factor alpha in MEEs were highly correlated with each other (P < .01 for each association) suggesting increased local production and the expected effects of cytokines stimulating their own production during OM. High concentrations of tumor necrosis factor alpha in MEEs were also associated with a history of multiple placements of tympanostomy tubes (r = .63).

CONCLUSIONS

These data suggest a regulatory role for cytokines in inflammation during OM, and suggest that high concentrations of tumor necrosis factor alpha in MEEs may be a marker for OM chronicity.

Natural killer (NK) activity in human responders and nonresponders to stimulation by anti-CD16 antibodies

Various anti-Fc gamma RIII (CD16) monoclonal antibodies (mAbs) are shown here to have positive or negative modulatory effects on human NK cells. Thus, 3G8 mAb (IgG1) triggered a dose-dependent augmentation of NK activity in 67% (23/34) of individuals tested, who were designated as responders. All four IgG1 anti-CD16 mAb tested (BL-LGL/1, B73.1, Leu11c, and 3G8) were stimulatory for NK cells isolated from responders, whereas six non-IgG1 anti-CD16 mAbs were either inhibitory or had no significant effects on NK activity. The upregulation of NK activity in responders was not attributable to an increase in either the conjugate formation or the delivery of the lethal hit to target cells. This mAb-mediated up-regulation of NK activity was shown to be associated with a recycling capacity higher than that of controls and with enhanced release of cytokines by activated NK cells. Anti-CD16 mAb inhibited binding of either monomeric or polymeric IgG to Fc gamma RIIIA on NK cells. Also, mAb 3G8 or its F(ab')2 fragments decreased or reversed inhibition of NK activity induced by monomeric IgG (mIgG). Our data indicate that regulation of NK activity via the Fc gamma RIIIA is influenced by dose-dependent interactions between cytophilic mIgG and anti-CD16 mAb of IgG1 isotype.

Variation of p53 mutational spectra between carcinoma of the upper and lower respiratory tract

Mutations of the p53 tumor suppressor gene are the most common genetic alterations associated with human cancer. Tumor-associated p53 mutations often show characteristic tissue-specific profiles which may infer environmentally induced mutational mechanisms. The p53 mutational frequency and spectrum were determined for 95 carcinomas of the upper and lower respiratory tract (32 lung and 63 upper respiratory tract). Mutations were identified at a frequency of 30% in upper respiratory tract (URT) tumors and 31% in lung tumors. All 29 identified mutations were single-base substitutions. Comparison of the frequency of specific base substitutions between lung and URT showed a striking difference. Transitions occurred at a frequency of 68% in URT, but only 30% in lung. Mutations involving G:C-->A:T transitions, which are commonly reported in gastric and esophageal tumors, were the most frequently identified alteration in URT (11/19). Mutations involving G:C-->T:A transversions, which were relatively common in lung tumors (3/10) and are representative of tobacco smoke-induced mutations were rare in URT tumors (1/19). Interestingly, G:C-->A:T mutations at CpG sites, which are characteristic of endogenous processes, were observed frequently in URT tumors (9/19) but only rarely in lung tumors (1/10), suggesting that both endogenous and exogenous factors are responsible for the observed differences in mutational spectra between the upper and lower respiratory systems.

Changes of liver-resident NK cells during liver regeneration in rats

To determine the role of NK cells in regulation of tissue growth, the phenotype and function of liver-resident NK cells were studied after 70% partial hepatectomy in rats. The process of liver regeneration was generally completed by day 14. In contrast, the number of liver-resident NK cells (NKR-P1bright) was restored as early as day 3 after partial hepatectomy. However, spontaneous functions of liver-resident NK cells, including killing of YAC-1 and P815 targets, Ab-dependent cellular cytotoxicity, and redirected killing via NKR-P1, were continuously suppressed throughout the entire period of liver regeneration (from 3 h to 14 days). Augmentation of NK cytotoxicity against P815 targets and induction of NK cell adherence to plastic following 24 h of IL-2 stimulation showed a similar pattern of suppression. However, IL-2-induced augmentation of YAC-1 killing, proliferation and generation of adherent NK cells, and LAK activity in 5- to 7-day cultures were found to be suppressed only during the first 24 h and increased between days 2 and 7 after hepatectomy. Sorted NK cells (> or = NKR-P1bright) from liver-resident mononuclear leukocytes 24 h after partial hepatectomy showed the same pattern of suppression as unsorted mononuclear leukocytes. In contrast to liver-resident NK cells, no significant changes were detected in peripheral blood or spleen NK cells of rats following partial hepatectomy. Of particular interest, in normal liver, hepatocytes were resistant to NK lysis, while resident NK cells were cytotoxic for various NK-sensitive targets. In contrast, during the early period of liver regeneration, when hepatocytes were sensitive to lysis by liver-resident NK cells of normal rats, NK cells obtained from regenerating liver tissues were unable to mediate cytotoxicity. At the final phase of liver regeneration (days 7-14 after hepatectomy), both resistance of hepatocytes to killing by NK cells and cytotoxicity of liver-resident lymphocytes against hepatocytes from regenerating liver were simultaneously restored. In vivo depletion of NK cells by injection of rats with anti-NKR-P1 mAb resulted in a significant augmentation of liver regeneration subsequent to partial hepatectomy. Our data suggest that liver-resident NK cells may be involved in regulation of the extent of liver regeneration.

Changes of liver-resident NK cells during liver regeneration in rats

To determine the role of NK cells in regulation of tissue growth, the phenotype and function of liver-resident NK cells were studied after 70% partial hepatectomy in rats. The process of liver regeneration was generally completed by day 14. In contrast, the number of liver-resident NK cells (NKR-P1bright) was restored as early as day 3 after partial hepatectomy. However, spontaneous functions of liver-resident NK cells, including killing of YAC-1 and P815 targets, Ab-dependent cellular cytotoxicity, and redirected killing via NKR-P1, were continuously suppressed throughout the entire period of liver regeneration (from 3 h to 14 days). Augmentation of NK cytotoxicity against P815 targets and induction of NK cell adherence to plastic following 24 h of IL-2 stimulation showed a similar pattern of suppression. However, IL-2-induced augmentation of YAC-1 killing, proliferation and generation of adherent NK cells, and LAK activity in 5- to 7-day cultures were found to be suppressed only during the first 24 h and increased between days 2 and 7 after hepatectomy. Sorted NK cells (&gt; or = NKR-P1bright) from liver-resident mononuclear leukocytes 24 h after partial hepatectomy showed the same pattern of suppression as unsorted mononuclear leukocytes. In contrast to liver-resident NK cells, no significant changes were detected in peripheral blood or spleen NK cells of rats following partial hepatectomy. Of particular interest, in normal liver, hepatocytes were resistant to NK lysis, while resident NK cells were cytotoxic for various NK-sensitive targets. In contrast, during the early period of liver regeneration, when hepatocytes were sensitive to lysis by liver-resident NK cells of normal rats, NK cells obtained from regenerating liver tissues were unable to mediate cytotoxicity. At the final phase of liver regeneration (days 7-14 after hepatectomy), both resistance of hepatocytes to killing by NK cells and cytotoxicity of liver-resident lymphocytes against hepatocytes from regenerating liver were simultaneously restored. In vivo depletion of NK cells by injection of rats with anti-NKR-P1 mAb resulted in a significant augmentation of liver regeneration subsequent to partial hepatectomy. Our data suggest that liver-resident NK cells may be involved in regulation of the extent of liver regeneration.

Natural killer (NK) cells as effectors of antibody-dependent cytotoxicity with chimeric antibodies reactive with human squamous-cell carcinomas of the head and neck

In patients with cancer, antibody-dependent cellular cytotoxicity (ADCC) may be used as a laboratory test or for enhancing immunotherapy with murine monoclonal or chimeric mouse/human anti-tumor antibodies (mMAbs or cMAbs, respectively). We have established an ADCC assay with IgG1 cMAb SF-25, using human squamous-cell carcinoma of the head and neck (SCCHN) cell lines as targets. By flow cytometry, all SCCHN cell lines tested expressed the antigen recognized by cMAb SF-25. Trypsinization of the cell monolayers facilitated binding of cMAb SF-25 to the antigen on the cell surface of SCCHN targets. Using the PCI-50 SCCHN cell line as a target coated with this cMAb at the optimal concentration of 1.0 micrograms/ml, normal human peripheral blood mononuclear cells (PBMC, n = 28) were found to mediate ADCC at a mean level of 283 +/- 42 (SEM) lytic units (LU20/10(7) effector cells). Non-adherent monocyte-depleted PBMC and natural killer (NK) cells purified by negative selection mediated significantly higher levels of ADCC than unseparated PBMC against SCCHN targets. NK cells, defined as CD3-CD56+ cells, could be effectively armed by cMAb SF-25, as confirmed by flow cytometry and ADCC assays. IL2-activated armed NK cells mediated higher levels of ADCC than non-armed NK cells. Binding of cMAb SF-25 to NK cells and their ADCC were enhanced by pre-incubation with polyethylene glycol. Arming of NK cells with chimeric antibodies should be considered in developing novel strategies for treatment of human SCCHN, especially in the adjuvant setting.

Autologous peripheral blood stem cell transplantation and adoptive immunotherapy with activated natural killer cells in the immediate posttransplant period

Relapse after high-dose chemotherapy supported by peripheral blood stem cell transplantation (HDC-PBSCT) is the main cause of therapeutic failure in patients with lymphoma and breast cancer. Adoptive immunotherapy with activated natural killer (A-NK) cells and interleukin 2 might eliminate surviving residual tumor without adding to toxicity. Eleven patients with relapsed lymphoma and one with metastatic breast cancer were entered on a pilot clinical trial of HDC-PBSCT followed on day 2 after transplant by infusion of cultured autologous A-NK cells. Simultaneously, recombinant human interleukin 2 (rhIL-2) was initiated as a 4-day continuous i.v. infusion at 2 x 10(6) IU/m2/day, referred to as high-dose rhIL-2. Therapy with high-dose rhIL-2 was followed by a 90-day continuous i. v. infusion at 3 x 10(5) IU/m2/day, referred to as low-dose rhIL-2. All patients engrafted and nine completed treatment. Posttransplant days to a neutrophil count of 500/microliter and to a platelet count of 50,000/microliter were similar to comparable patients treated with HDC-PBSCT alone. Generation of A-NK cells for therapy was feasible in all patients except the three patients with Hodgkin's disease, whose cells did not proliferate in culture. Overall toxicity associated with early posttransplant transfer of A-NK cells and interleukin 2 did not differ from that observed with peripheral blood stem cell transplantation alone in comparable patients. There was early amplification of natural killer cell activity in the peripheral blood of four patients that appeared to result from the transfused A-NK cells. Adoptive transfer of A-NK cells and rhIL-2 during the pancytopenic phase after HDC-PBSCT was feasible and well tolerated, did not adversely affect engraftment, and resulted in amplified natural killer activity in the peripheral blood during the immediate posttransplantation period.

In situ interleukin-4 gene expression in cancer patients treated with genetically modified tumor vaccine

Patients with advanced malignancies, participating in our ongoing phase I interleukin-4 (IL-4) gene therapy protocol at the Pittsburgh Cancer Institute, were vaccinated with irradiated autologous tumor cells together with IL-4 gene-transduced irradiated autologous fibroblasts. The level of expression of the IL-4 gene in cultured transduced and selected fibroblasts and in biopsies obtained from vaccination sites was evaluated using quantitative reverse transcription-polymerase chain reaction (RT-PCR). The number of copies of IL-4 mRNA/ng of total cellular RNA was determined in the transduced fibroblasts. Good agreement was observed between IL-4 message expression, as determined by RT-PCR, and IL-4 production, as determined by enzyme-linked immunosorbent assay (ELISA) in the fibroblast supernatants. Tissue biopsies of multiple vaccination sites were obtained from the patients to determine the level of gene expression in situ for IL-4 and Neo-r. The Neo-r gene was used as a marker for transduced fibroblasts. Two weeks after the first vaccination, mRNA for the IL-4 gene was still detectable in all tissue biopsies. The Neo-r gene was also detectable, indicating the presence of transduced fibroblasts in the biopsy. After the second vaccination, expression of the IL-4 and Neo-r genes was generally the highest on day 1 after vaccine administration and was considerably lower but still detectable on day 14 in all biopsies tested. These data indicate that autologous dermal fibroblasts transduced with the IL-4 and Neo-r genes and used as a source of IL-4 in tumor vaccine are able to express the IL-4 gene in vivo.

Assessment of sensitivity and specificity of immunohistochemical staining of p53 in lung and head and neck cancers

Thirty-two primary carcinomas of the lung and 17 carcinomas of the head and neck (HN) were systematically analyzed for p53 mutations in the highly conserved regions of the gene (exons 5-8). Frozen sections of the same tumors were stained immunohistochemically to assess the sensitivity and specificity of p53 expression as determined by the presence or absence of the protein. On the basis of histology, the lung tumors studied were divided into adenocarcinomas (AC; n = 15), squamous-cell carcinomas (SCC; n = 12), and large-cell carcinomas (LCC; n = 5). All the HN cancers were SCC. Mutations in the p53 gene were detected by direct sequencing of amplified polymerase chain reaction products in six AC of the lungs (40%), three SCC of the lungs (25%), and one LCC (20%), with an overall mutation frequency of 31%. Nine AC (60%) of the lungs, five SCC (42%), and four LCC (80%) were p53-positive by immunohistochemistry. Among HN cancers, p53 mutations were detected in seven tumors (41%). Nine HN tumors (53%) were positive for p53. Negative staining, despite the presence of p53 mutations, was confined to nonsense mutations with truncated p53 and to single-base mutations not causing any change in the amino acid. Although immunohistochemical staining for mutated p53 is sensitive and simple to perform as a screening method, it is not as specific for evaluation of p53 mutations in lung and HN cancers.

Induction of protein tyrosine phosphorylation in human natural killer cells by triggering via alpha 4 beta 1 or alpha 5 beta 1 integrins

Recent studies have shown that cell-surface integrins expressed on platelets, fibroblasts, or carcinoma cell lines serve not only as adhesion receptors that connect the extracellular matrix to the cytoskeleton, but also as signal-transducing molecules involved in altering cellular patterns of tyrosine phosphorylation. In this present report we provide evidence that adhesion of freshly purified human natural killer (NK) cells to fibronectin (FN) induces tyrosine phosphorylation of intracellular proteins of approximate molecular mass of 60, 70, and 120 kD. Increases in phosphorylation induced by NK cell binding to immobilized FN were partially blocked by EILDV- (CS-1) or RGD-containing peptides, which compete specifically for a distinct binding site for either alpha 4 beta 1 or alpha 5 beta 1 integrins, respectively, within the FN molecule. The presence of either one of the inhibitory peptides alone inhibited tyrosine phosphorylation primarily during short-term (30 minutes) and, to a lesser extent, during long-term (2 to 3 hours) periods of adhesion. These observations indicate that triggering either via alpha 4 beta 1 or alpha 5 beta 1 integrins, which are constitutively expressed on NK cells, induces protein tyrosine phosphorylation. Moreover, FN fragments of 40 or 120 kD, known to contain the binding sites for alpha 4 beta 1 or alpha 5 beta 1 integrins, respectively, used as immobilized substrates for NK cell adhesion, were able to initiate tyrosine kinase activity. The induced tyrosine phosphorylation was observed mainly on intracellular proteins of greater than 50 kD molecular weight. We have identified a 70-kD tyrosine phosphoprotein as paxillin, a cytoskeletal-associated tyrosine kinase substrate previously identified in fibroblasts and shown to localize to focal adhesions. Thus, interaction of NK cells with immobilized extracellular matrix glycoproteins required for migration and extravasation of these cells involves activation of intracellular protein tyrosine kinases and tyrosine phosphorylation of cytoskeleton-associated protein, paxillin, which may play a role in signaling between beta 1 integrins and the underlying cytoskeleton.

Potentiation of lysis of leukaemia cells by a bispecific antibody to CD33 and CD16 (Fc gamma RIII) expressed by human natural killer (NK) cells

Bispecific antibodies recognizing tumour-associated antigens and trigger molecules expressed on immune effector cells have been shown to redirect cytotoxicity of several types of peripheral blood cells against relevant tumour targets. Among various effector cells, natural killer (NK) cells appear to play a role in defence against leukaemia. Here we report the successful chemical conjugation of monoclonal antibodies to CD33 and CD16 to create a bispecific antibody (BsAb 251 x 3G8). This bispecific antibody is capable of augmenting the killing of otherwise resistant leukaemia cells by peripheral blood lymphocytes (PBL), purified resting NK (R-NK) cells, and activated NK (A-NK) cells. BsAb 251 x 3G8 may play a role in the therapy of acute myeloid leukaemia (AML) through redirecting the cytotoxic activity of endogenous or adoptively transferred NK cells.

Production by human squamous cell carcinoma of a factor inducing activation and proliferation of immune cells

OBJECTIVE

To examine supernatants (SNs) of human squamous cell carcinoma of the head and neck cell lines for soluble tumor-derived factors capable of inducing activation and proliferation of human immune cells.

DESIGN

The SN of squamous cell carcinoma of the head and neck cell line PCI-50 was cultured in serum-free medium and tested for the ability to induce expression of activation antigens, proliferation, cytotoxicity against tumor cell targets and cytokine production by purified human natural killer (NK) and CD4+ T cells.

RESULTS

Supernatant of PCI-50 promoted expression of the following activation markers on NK and T cells: CD25 (interleukin-2R-alpha), HLA-DR (major histocompatibility complex class II), CD54 (ICAM-1), CD71 (transferrin receptor), and CD69 (activation-inducing molecule). In addition, SN induced and significantly sustained (P < .01) proliferation of human unseparated peripheral blood lymphocytes and NK or T cells in culture. Purified human NK or T cells cultured in the presence of the SN and IL-2 (120 IU/mL) had significantly higher antitumor cytotoxicity than that mediated by NK or T cells cultured in AIM-V medium and IL-2. The SN induced cytokine (interferon gamma, tumor necrosis factor alpha, interleukin-6) production in purified NK or T cells. When the SN was fractionated by molecular weight-based filtration into fractions greater and less than 30 kd, the growth- and cytotoxicity-promoting activities were consistently detectable in the greater than 30-kd fraction.

CONCLUSIONS

Culture SN of squamous cell carcinoma of the head and neck cell lines contain a soluble factor(s) capable of activating NK and CD4+ T cells and of promoting growth and antitumor cytotoxicity of these lymphocyte subsets in vitro.

Expression of vitronectin receptor on human NK cells and its role in protein phosphorylation, cytokine production, and cell proliferation

In this paper, we provide evidence that the vitronectin receptor (VNR) alpha v beta 3 is expressed on human NK cells. The presence of this VNR on freshly purified NK cells was demonstrated by flow cytometry analysis, as well as biochemically, after 125I-labeled surface lactoperoxidase labeling and immunoprecipitation. mAbs LM142 and LM609 specific for alpha v and alpha v beta 3, respectively, precipitated a heterodimer of alpha- and beta-chains with approximate molecular masses of 155 and 110 kDa under nonreducing conditions. Under reducing conditions, there was an apparent decrease in the molecular mass of the alpha-chain, which is likely to result from the release of a protein of 20 to 30 kDa linked by internal disulfide bond to the alpha v-chain. Integrin alpha v beta 3 expressed on NK cells became functional, i.e., was able to bind its ligand, vitronectin (VN), only after cellular activation or when costimulation with an additional signal was provided. Thus, NK cells adhered to plastic-immobilized VN only after IL-2 activation, and RGD-containing synthetic peptides or mAbs specific for alpha v beta 3 complex inhibited this binding. To assess the role of the VNR in signal transduction, anti-beta 3 mAb was used to cluster the VNR on NK cells and, thereby, mimic the process that occurs during formation of adhesive contacts. Cross-linking of VNR on fresh NK cells stimulated phosphorylation on tyrosine residues of several intracellular proteins. The major increase in tyrosine phosphorylation was observed in proteins of approximate molecular masses of 75 and 120 kDa. Therefore, signal transduction by the VNR on NK cells induced activation of intracellular protein kinases. Ligand engagement of the VNR on NK cells also costimulated cytokine production and proliferation of NK cells. Binding of NK cells to plastic-immobilized VN served as a costimulus with either anti-Fc gamma RIII or IL-2 to produce IFN-gamma, TNF-alpha, and cell proliferation. Our findings suggest that occupancy and subsequent clustering of VNRs play a role in the activation and function of human NK cells.

Expression of vitronectin receptor on human NK cells and its role in protein phosphorylation, cytokine production, and cell proliferation

In this paper, we provide evidence that the vitronectin receptor (VNR) alpha v beta 3 is expressed on human NK cells. The presence of this VNR on freshly purified NK cells was demonstrated by flow cytometry analysis, as well as biochemically, after 125I-labeled surface lactoperoxidase labeling and immunoprecipitation. mAbs LM142 and LM609 specific for alpha v and alpha v beta 3, respectively, precipitated a heterodimer of alpha- and beta-chains with approximate molecular masses of 155 and 110 kDa under nonreducing conditions. Under reducing conditions, there was an apparent decrease in the molecular mass of the alpha-chain, which is likely to result from the release of a protein of 20 to 30 kDa linked by internal disulfide bond to the alpha v-chain. Integrin alpha v beta 3 expressed on NK cells became functional, i.e., was able to bind its ligand, vitronectin (VN), only after cellular activation or when costimulation with an additional signal was provided. Thus, NK cells adhered to plastic-immobilized VN only after IL-2 activation, and RGD-containing synthetic peptides or mAbs specific for alpha v beta 3 complex inhibited this binding. To assess the role of the VNR in signal transduction, anti-beta 3 mAb was used to cluster the VNR on NK cells and, thereby, mimic the process that occurs during formation of adhesive contacts. Cross-linking of VNR on fresh NK cells stimulated phosphorylation on tyrosine residues of several intracellular proteins. The major increase in tyrosine phosphorylation was observed in proteins of approximate molecular masses of 75 and 120 kDa. Therefore, signal transduction by the VNR on NK cells induced activation of intracellular protein kinases. Ligand engagement of the VNR on NK cells also costimulated cytokine production and proliferation of NK cells. Binding of NK cells to plastic-immobilized VN served as a costimulus with either anti-Fc gamma RIII or IL-2 to produce IFN-gamma, TNF-alpha, and cell proliferation. Our findings suggest that occupancy and subsequent clustering of VNRs play a role in the activation and function of human NK cells.

Antitumor activities of subsets of human IL-2-activated natural killer cells in solid tissues

Human NK cells can be separated into two functionally distinct subpopulations based on the ability to rapidly respond to IL-2 by adherence to solid surfaces. To determine functions of the NK cell subsets in solid tumor tissues, adherent (A) and nonadherent (NA) NK cells were evaluated for their ability to infiltrate multicellular tumor spheroids in vitro, to kill carcinoma (CA) cell targets in these spheroids, and to mediate antitumor activity in vivo. A-NK cells were less cytolytic than NA-NK cells against CA targets in single cell suspensions or in monolayers. However, A-NK cells showed a significantly better ability than NA-NK cells to infiltrate tumor tissues and kill tumor cells in spheroids of human squamous cell CA of the head and neck or breast CA. Perilesional delivery of human A-NK cells and IL-2 resulted in regression of established human squamous cell carcinoma of the head and neck tumors growing subcutaneously in immunosuppressed nude mice. Similarly, in a xenograft model of human gastric CA metastatic to liver of nude mice, a single intrasplenic injection of A-NK cells in combination with i.p. infusions of IL-2 significantly reduced the number of established hepatic metastases (p < 0.007) and prolonged survival of the mice (p < 0.003). In contrast, NA-NK cells were ineffective in either of the in vivo xenograft tumor models. These findings demonstrate that A-NK cells represent a biologically unique and important subset of NK cells that, in contrast to the rest of NK cells, function as effector cells in solid tumor tissues and, consequently, have a great antitumor therapeutic potential.

Antitumor activities of subsets of human IL-2-activated natural killer cells in solid tissues

Human NK cells can be separated into two functionally distinct subpopulations based on the ability to rapidly respond to IL-2 by adherence to solid surfaces. To determine functions of the NK cell subsets in solid tumor tissues, adherent (A) and nonadherent (NA) NK cells were evaluated for their ability to infiltrate multicellular tumor spheroids in vitro, to kill carcinoma (CA) cell targets in these spheroids, and to mediate antitumor activity in vivo. A-NK cells were less cytolytic than NA-NK cells against CA targets in single cell suspensions or in monolayers. However, A-NK cells showed a significantly better ability than NA-NK cells to infiltrate tumor tissues and kill tumor cells in spheroids of human squamous cell CA of the head and neck or breast CA. Perilesional delivery of human A-NK cells and IL-2 resulted in regression of established human squamous cell carcinoma of the head and neck tumors growing subcutaneously in immunosuppressed nude mice. Similarly, in a xenograft model of human gastric CA metastatic to liver of nude mice, a single intrasplenic injection of A-NK cells in combination with i.p. infusions of IL-2 significantly reduced the number of established hepatic metastases (p &lt; 0.007) and prolonged survival of the mice (p &lt; 0.003). In contrast, NA-NK cells were ineffective in either of the in vivo xenograft tumor models. These findings demonstrate that A-NK cells represent a biologically unique and important subset of NK cells that, in contrast to the rest of NK cells, function as effector cells in solid tumor tissues and, consequently, have a great antitumor therapeutic potential.

Proliferation of hematopoietic cell lines induced by a soluble factor derived from human squamous cell carcinomas of the head and neck

The supernatant of a cell line of squamous cell carcinoma of the head and neck (SCCHN), PCI-50, was previously shown to induce activation, promote proliferation and increase antitumor cytotoxicity of freshly purified human natural killer (NK) cells and CD4+ T lymphocytes [Arch Otolaryngol Head Neck Surg (1994) in press]. This supernatant was found also to promote the growth of a variety of hematopoietic cell lines, including Jurkat, THP-1, K562, NK-92 or Epstein-Barr-virus-transformed B cell lines. The Jurkat cell line was selected as a reporter cell in an 18-h proliferation assay established to measure the growth-promoting activity of PCI-50 supernatant. The presence of soluble tumor-derived factors able to induce proliferation of Jurkat cells was demonstrated in the supernatant produced by several other SCCHN cell lines but not in that produced by a gastric cancer cell line (HR) or renal cell carcinoma line (5117G8). The growth-promoting PCI-50 supernatant was shown to contain 28 +/- 0.5 pg/ml interleukin-6 (IL-6) in vitro but was negative for interferon gamma, IL-1, IL-2, IL-4, tumor necrosis factor alpha, granulocyte/macrophage-colony-stimulating factor and IL-12. The addition of any of these recombinant cytokines to Jurkat cell cultures did not significantly promote growth, while PCI-50 supernatant was consistently growth-stimulatory. This supernatant neither enhanced intracellular Ca2+ concentration in Jurkat cells nor induced up-regulation of activation antigens on the cell surface, although it supported growth of Jurkat cells in the absence of IL-2. The growth-promoting activity in the PCI-50 supernatant was acid-labile at pH 2 for 4 h, heat-resistant at 96 degrees C for 1 h and sensitive to treatments with trypsin and pepsin. Preincubation of the PCI-50 producer cells with tunicamycin or cyclohexamide reduced the level of growth-promoting activity in the supernatant. A partial purification of this activity was achieved using Amicon filtration, chromatography on concanavalin-A-Sepharose and then a hydroxyapatite column and high-pressure liquid chromatography gel filtration. The partially purified glycoprotein had a molecular mass of 50-70 kDa, as determined by gel filtration.

Effects of therapy with interferon-alpha on peripheral blood lymphocyte subsets and NK activity in patients with chronic hepatitis C

Longitudinal changes in lymphocyte subpopulations, including total and activated T cells, B cells, and NK cells as well as NK activity and 2',5'-oligoadenylate synthetase (2'5' AS) levels were determined in peripheral blood before, during, and after therapy with human recombinant interferon-alpha (HurIFN-alpha) in 39 patients with serologically and biopsy-confirmed chronic hepatitis C. Immunologic data obtained at baseline and during IFN-alpha administration were correlated with the clinical response to IFN-alpha therapy defined as a normalization of the serum alanine aminotransferase level. There were 23 responders (R) and 13 nonresponders (NR) to IFN-alpha and 3 patients were not evaluable. Prior to the use of IFN-alpha, the patients tended to have higher numbers of activated (DR+) T and NK cells but a lower number of CD3+CD25+ T cells than normal controls. During IFN-alpha therapy, highly significant induction of 2'5'AS was observed. The numbers of circulating WBC, total lymphocytes, and T and B cells were reduced during IFN-alpha therapy. In contrast, both the absolute number and percentage of activated CD3+CD25+ and CD4+DR+ T cells increased in response to the IFN-alpha therapy. The percentage of activated CD56+DR+ NK cells was also significantly elevated over the pretreatment baseline. IFN-alpha therapy had no effect on NK activity in peripheral blood mononuclear cells. No differences in the immunologic profile of R vs NR were noted, except that the number of IL2R+ T cells was increased transiently early during IFN-alpha therapy but only in the NR group. It was not possible to reliably discriminate between R vs NR to IFN-alpha therapy on the basis of longitudinal changes in the phenotype or function of immune effector cells.

Cytokine measurements and interpretation of cytokine assays in human disease

Cytokines are powerful mediator and communication molecules capable of regulating a wide spectrum of biologic functions, including immune responses. Although the role of cytokines in the pathogenesis of human disease is not yet understood, assays for cytokines have become a common feature in research and clinical laboratories. However, numerous pitfalls accompany measurements of cytokine levels in body fluids and of cytokine synthesis or gene expression in tissue. Interpretation of results obtained in cytokine assays, especially those performed with pathologic specimens, is fraught with difficulties. While cytokine assays are clearly of value in monitoring patients treated with recombinant cytokines or receiving anticytokine therapy, the clinical significance of cytokine assays is not yet fully established. In this review, some of the complexities associated with cytokine monitoring are discussed. The crucial importance of understanding cytokine biology for meaningful assay interpretation is emphasized.

Expression and function of Fc gamma RII on human natural killer cells

In this report, we present data on the expression and function of Fc gamma RII (CD32) by natural killer (NK) cells. Highly enriched NK cell populations were isolated from peripheral blood lymphocytes by negative selection and consisted of > or = 95% CD3-/CD56+ cells. Flow cytometric analyses with anti-CD32 monoclonal antibodies (mAbs) demonstrated that a small proportion of NK cells were recognized by mAbs IV.3 and 41H16. Two-color flow cytometric analysis indicated coexpression of the epitope on NK cells recognized by both these mAbs. Verification of expression of CD32 on NK cells was obtained by demonstrating coexpression of CD32 on either CD16+ or CD56+ cells. The CD32+/CD16+ and CD32+/CD56+ cells represented approximately 7 and 3% of the total, respectively. CD32 transcripts were identified from highly purified NK cells using reverse transcription-polymerase chain reaction with CD32-specific primers, followed by Southern blotting. Enhanced chemiluminescence-Western blot (ECL-WB) analysis of lysates of purified NK cells indicated that mAb IV.3 recognized a molecule of approximately 40 kD. The Fc gamma RII on NK cells was able to transduce intracellular signals in several types of assay. Cross-linking of anti-CD32 resulted in a mobilization of intracellular Ca2+, although to a lesser extent than that induced by cross-linking CD16. Both mAbs IV.3 and 41H16 were found to be capable of inducing reverse antibody-dependent cellular cytotoxicity against FcR+ target cells (e.g. P815). These data represent the first direct description of the expression and function of Fc gamma RII on human NK cells.

Signaling via CD7 molecules on human NK cells. Induction of tyrosine phosphorylation and beta 1 integrin-mediated adhesion to fibronectin

We have previously reported that CD7 expressed on resting human NK cells is a signal-transducing molecule, which upon ligation with mAb induces a rapid increase in cytoplasmic free calcium, secretion of IFN-gamma, and augmented NK activity against K562 targets. We now demonstrate that Ab-mediated clustering of CD7 molecules on NK cells results in enhanced phosphorylation on tyrosine residues of intracellular proteins of 60, 70, 80, 97, and 120 kDa. In the presence of genistein, a specific inhibitor of protein tyrosine kinase, the enhanced level of tyrosine phosphorylation was blocked, indicating that CD7 may induce signaling via activation of tyrosine kinases. Cross-linking of CD7 or CD16 molecules with primary and secondary Abs, as well as stimulation of NK cells with phorbol ester (PMA) or with calcium ionophore A23187 also induced beta 1 integrin-mediated adhesion of these cells to fibronectin (FN)-coated plastic surfaces. In contrast, cross-linking of CD2 expressed on the surface of NK cells had no significant effect on NK cell adhesion to FN. This adhesion was not associated with up-regulation of expression of alpha 4 beta 1 or alpha 5 beta 1 FN receptors on NK cells, but it required an intact cytoskeleton. The CD7-induced adhesion to FN was mediated by alpha 4 beta 1 and alpha 5 beta 1 integrins, as it was partially blocked by FN connective segment-1 peptide (EILDVPST), the alpha 4 beta 1-binding domain, as well as by RGD-containing peptides, the alpha 5 beta 1-binding domain, but not by EILEVPST or RGE control peptides. NK cell binding to FN was also partially inhibited by mAb to alpha 4, alpha 5, and beta 1 integrins. The mechanism by which cross-linking of CD7 or CD16 on NK cells induced adhesion to FN appeared to involve both protein tyrosine kinase and protein kinase C, because this adhesion was blocked in the presence of either genistein or a protein kinase C inhibitor, staurosporin. Our data demonstrate that signals transduced via triggering of either CD7 or CD16 molecules are involved in the regulation of the functional activity of beta 1 integrins on NK cells.

Expression of interleukin 2 receptors on human carcinoma cell lines and tumor growth inhibition by interleukin 2

We have previously shown that human squamous cell carcinomas (SCC) express the interleukin 2 receptor (IL2R)-alpha and -beta chains, and that the ligand, IL2, directly inhibits growth of the tumor in vitro and in vivo in the tumor xenograft-nude mice model. We now show that the alpha and beta chains of IL2R are expressed on a variety of human carcinoma cell lines and on normal human keratinocytes in early-stage cultures. While all carcinoma cells in a population expressed IL2R-alpha and -beta proteins, in keratinocytes obtained from different normal donors, variable proportions of cells were positive, as measured by flow cytometry. The carcinoma lines and 2/5 keratinocyte lines studied were also found to contain transcripts for the IL2R-gamma chain detectable by combined reverse transcription-PCR (RT-PCR) and hybridization with the specific cDNA probe. Incubation of the gastric (HR) or renal cell carcinoma (RCC) cell lines, but not of other IL2R+ carcinoma cell lines or normal keratinocytes, in the presence of IL2 resulted in dose-dependent inhibition of tumor cell growth. Monoclonal antibodies (MAbs) specific for IL2R-beta chain completely reversed this growth inhibitory effect of IL2. The ligand, IL2, also down-regulated surface expression of its own receptor and of intercellular adhesion molecule-I (ICAM-I) or class I major histocompatibility complex (MHC) antigens on IL2R+ tumor cells. All carcinoma cells studied incubated in the presence of IL2 exhibited significantly increased sensitivity to growth-inhibitory effects of other cytokines such as interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha or transforming growth factor (TGF)-beta. IL2 inhibited growth of the HR cells by arresting a significant proportion of tumor cells in the G0/G1 phase of the cell cycle. Thus, IL2 can have direct effects on IL2R+ carcinoma cells, leading to changes in growth or to increases in sensitivity of tumor cells to cytostatic activities of other cytokines.

Signaling via CD7 molecules on human NK cells. Induction of tyrosine phosphorylation and beta 1 integrin-mediated adhesion to fibronectin

We have previously reported that CD7 expressed on resting human NK cells is a signal-transducing molecule, which upon ligation with mAb induces a rapid increase in cytoplasmic free calcium, secretion of IFN-gamma, and augmented NK activity against K562 targets. We now demonstrate that Ab-mediated clustering of CD7 molecules on NK cells results in enhanced phosphorylation on tyrosine residues of intracellular proteins of 60, 70, 80, 97, and 120 kDa. In the presence of genistein, a specific inhibitor of protein tyrosine kinase, the enhanced level of tyrosine phosphorylation was blocked, indicating that CD7 may induce signaling via activation of tyrosine kinases. Cross-linking of CD7 or CD16 molecules with primary and secondary Abs, as well as stimulation of NK cells with phorbol ester (PMA) or with calcium ionophore A23187 also induced beta 1 integrin-mediated adhesion of these cells to fibronectin (FN)-coated plastic surfaces. In contrast, cross-linking of CD2 expressed on the surface of NK cells had no significant effect on NK cell adhesion to FN. This adhesion was not associated with up-regulation of expression of alpha 4 beta 1 or alpha 5 beta 1 FN receptors on NK cells, but it required an intact cytoskeleton. The CD7-induced adhesion to FN was mediated by alpha 4 beta 1 and alpha 5 beta 1 integrins, as it was partially blocked by FN connective segment-1 peptide (EILDVPST), the alpha 4 beta 1-binding domain, as well as by RGD-containing peptides, the alpha 5 beta 1-binding domain, but not by EILEVPST or RGE control peptides. NK cell binding to FN was also partially inhibited by mAb to alpha 4, alpha 5, and beta 1 integrins. The mechanism by which cross-linking of CD7 or CD16 on NK cells induced adhesion to FN appeared to involve both protein tyrosine kinase and protein kinase C, because this adhesion was blocked in the presence of either genistein or a protein kinase C inhibitor, staurosporin. Our data demonstrate that signals transduced via triggering of either CD7 or CD16 molecules are involved in the regulation of the functional activity of beta 1 integrins on NK cells.

Comparison of in vivo and in vitro prostaglandin E2 production by squamous cell carcinoma of the head and neck

Prostaglandin E2 has been identified as an immunosuppressive factor in patients with squamous cell carcinoma of the head and neck. Spontaneous prostaglandin E2 production by 21 cancer cell lines, which were obtained from 17 patients with squamous cell carcinoma of the head and neck, was determined by radioimmunoassay. In comparison with normal keratinocyte cultures, prostaglandin E2 production by cancer cell lines was significantly decreased (p < 0.0001). Prostaglandin E2 levels demonstrated no correlation to the site, stage, or histopathologic differentiation of the tumor. In a separate group of 17 patients with squamous cell carcinoma of the head and neck, tumor cells were isolated from fresh tumor specimens, and 24-hour PGE2 production in vitro was assayed. No correlation was found with tumor site, stage, or 2-year disease-free survival. Although prostaglandin E2 may have biologic significance in vivo in patients with squamous cell carcinoma of the head and neck, these findings suggest that measurements of tumor cell-derived prostaglandin E2 are not predictive of biologic behavior.

Immunotherapy of liver metastases of human gastric carcinoma with interleukin 2-activated natural killer cells

To better understand the events occurring during immunotherapy of liver metastases with effector cells, we have developed a clinically relevant animal model in which both effector-tumor cell interactions and survival can be evaluated. A cell line of human gastric carcinoma (HR) metastatic to the liver has been established from a patient's liver biopsy. HR cells (10 x 10(6)) injected intrasplenically metastasize into the liver of immunosuppressed nude mice, with micrometastases detectable histologically by day 4 and macrometastases by day 7. The animals subsequently develop ascites and die between days 30 and 40 after tumor injection. To investigate early metastatic events in the liver, HR cells were transduced with a plasmid containing both the lacZ gene under the control of the CMV promoter and NeoR gene. Transfectants selected for neomycin resistance were lacZ gene positive and stained blue in the presence of a beta-galactosidase substrate, 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-Gal). These transfectants (HRLZ) remained lacZ gene positive for at least 25 passages in vitro. Injected intrasplenically, an HRLZ clone grew invasively in nude mice and formed liver metastases comparably to parental tumor cells. The number and localization of blue X-Gal-positive tumor cells were followed in liver tissues of animals sacrificed at various times, from 1 h to 28 days postinjection of HRLZ cells. HRLZ cells were seen in liver blood vessels and sinusoids within 1 h after injection, and the progressive growth of micrometastases and macrometastases could be followed with precision by X-Gal staining. On day 3 after injection of HRLZ cells, numerous micrometastases were established containing 12-16 tumor cells. When these 3-day established HRLZ micrometastases were treated by the intrasplenic infusion of interleukin 2 (IL2)-activated human natural killer (NK) cells selected by IL2-induced adherence to plastic (A-NK) and systemic IL2, nearly all liver micrometastases were eliminated within 24 h after a single transfer of A-NK cells (P < 0.001). This xenogeneic model was also used for adoptive immunotherapy of 7-day established liver macrometastases with human A-NK cells injected intrasplenically and exogenous IL2 given i.p. A significant decrease in the number of hepatic metastases and the weight of livers (P < 0.003) in comparison with those of control mice was observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Cellular immunity in depressed, conduct disorder, and normal adolescents: role of adverse life events

OBJECTIVE

To determine whether adolescents with major depressive disorder have disturbances in their cellular immunity and to study whether the immunological changes detected are specific to depression or are general responses to stress.

METHOD

Twenty subjects with major depressive disorder, 17 nondepressed subjects with conduct disorder, and 17 normal adolescents were recruited. Subjects were assessed with a clinical interview for DSM-III-R and a modified version of the Coddington Life Events Checklist. Blood samples were drawn for total white blood cells, lymphocytes subsets, natural killer cell activity, lymphocyte proliferation response to phytohemagglutinin, and cortisol plasma levels.

RESULTS

Overall, there were no significant between-group differences in any of the cellular immune measurements. Natural killer cell activity was significantly negatively correlated with past year and lifetime adverse life events across all effector-target cell ratios. Controlling for diagnoses and socioeconomic status yielded similar results. There were no significant effects of age, sex, race, sleep, nutrition, cigarette use, menstrual cycle, or cortisol on any of the immunological variables.

CONCLUSIONS

In this sample of adolescents, we found that independent of the diagnoses and socioeconomic status, increases in adverse life events were associated with low natural killer cell activity.

HLA restriction and T-cell-receptor V beta gene expression of cytotoxic T lymphocytes reactive with human squamous-cell carcinoma of the head and neck

A human cytotoxic-T-lymphocyte (CTL) line capable of killing autologous tumor (AuTu) cell targets was established from peripheral-blood lymphocytes of a patient with squamous-cell carcinoma of the tongue. The cultured CTL were CD3+CD8+CD11b-HLA-DR+T cell receptor (TCR) alpha/beta+. When tested in 4-hr 51Cr-release assays against various lines of squamous-cell carcinoma of the head and neck (SCCHN) and a variety of non-squamous human tumor and normal cell targets, the CTL were found to lyse the autologous SCCHN cell line (PCI-50) and 7 allogeneic SCCHN lines: PCI-1, -2, -4A, -4B, -13, -30 and -38. Of these tumor cell lines, PCI-13, -30 and -38 shared HLA-A2 locus with the AuTu, PCI-50, while PCI-4A and -4B shared HLA-B44 with AuTu. Lysis of AuTu (A2+B44+), PCI-13 (A2+B44-) and PCI-4B (A2- B44+) by the CTL was efficiently inhibited by monoclonal antibodies (MAbs) to CD3, CD8, TCR alpha/beta or the major-histocompatibility-complex (MHC)-class-I antigens. MAbs to HLA-A2 antigens inhibited lysis of PCI-50 or PCI-13 targets by the CTL. In cold-target inhibition assays, unlabeled PCI-4B or PCI-13 cells inhibited CTL lysis of AuTu targets. The CTL incubated in the presence of the HLA-A2+ SCCHN PCI-50 or -13, but not an HLA-A2+ gastric carcinoma, produced TNF-alpha, IFN-gamma and GM-CSF. The CTL were tested for their TCR V beta gene expression by polymerase chain reaction (PCR). At week 10 in culture, the time of the highest AuTu cytotoxicity mediated by the CTL line, V beta 6 was expressed by 26% of T cells. Three clones, obtained by limiting dilution from 10-week CTL and selected for high cytotoxicity against AuTu, were found to be V beta6+. Further analysis of the specificity of these clones indicated lytic activity against PCI-13 (A2+B44-), but not PCI-4B (A2-B44+) targets. In 16-week cultures, which retained AuTu cytotoxicity as well as V beta 6 expression, TCR V beta 2 was also expressed at high frequency (29%), and AuTu-reactive clones were found to be V beta 2+. Our results indicate that at least 2 different CTL populations (V beta 6+ and V beta 2+) are able to recognize SCCHN-associated antigen(s) and that the V beta 6+ T cells are HLA-A2 restricted, while V beta 2+ T cells may be HLA-B44 restricted.

In vitro cytokine production by normal human peripheral blood mononuclear cells as a measure of immunocompetence or the state of activation

Measurements of cytokine levels in serum may not adequately reflect the cytokine-producing potential of immune cells because of the short half-lives of cytokines and the presence of various inhibitors in human sera. In vitro cytokine production by peripheral blood mononuclear cells (PBMCs) can be an important and reliable measure of immunocompetence. Also, spontaneous in vitro release of cytokines by PBMCs may serve as a measure of their activation in vivo. In the present study, normal ranges for the in vitro production by PBMCs of interleukin-1 beta (IL-1 beta), tumor necrosis factor alpha (TNF-alpha), IL-2, and gamma interferon (IFN-gamma) were established; the feasibility of using cryopreserved PBMCs for assays of in vitro cytokine production was evaluated; and spontaneous (unstimulated) versus induced production of cytokines by fresh and cryopreserved PBMCs from healthy donors was compared. Supernatants obtained from paired fresh and frozen PBMCs were quantitated for IL-1 beta, TNF-alpha, IL-2, and IFN-gamma by using enzyme-linked immunosorbent assay or a radioimmunoassay standardized against World Health Organization cytokine standards. Fresh or cryopreserved PBMCs activated with lipopolysaccharide produced comparable levels of IL-1 beta. However, the mean levels of stimulated production of TNF-alpha, IFN-gamma, and IL-2 were significantly higher in cryopreserved versus fresh PBMCs (P < or = 0.0004). Correlations between the level of production of each cytokine by fresh versus cryopreserved in vitro-stimulated PBMCs were statistically significant, although of moderate magnitude. Spontaneous cytokine release by fresh versus cryopreserved cells was not significantly different.

Role of human natural killer cells in health and disease

Natural killer (NK) cells, the CD3- CD56+ CD16+ subset of peripheral blood lymphocytes, have long been known to be involved in non-major histocompatibility complex-restricted natural immunity to virally infected and malignant target cells. The association of abnormalities in NK cell numbers or functions with a broad spectrum of human diseases has been more clearly defined in recent years as a result of the improved knowledge of NK cell physiology and advances in monitoring of NK cell functions in health and disease. The ability to reliably measure changes in NK activity and/or numbers during the course of disease or response to treatment has focused attention on the role of the NK cell in disease pathogenesis. The improved understanding of NK cell deficiency in disease has opened a way for therapies specifically designed to improve NK cell function. The therapeutic use of biologic response modifiers capable of augmenting NK cell activity in vivo and of adoptive transfer of highly enriched, activated autologous NK cells in diseases such as cancer and AIDS is being evaluated. The importance of NK cells in health and the consequences of NK cell deficiency or excess are likely to be more extensively monitored in the future.

Natural killer cells and gene therapy: potential of gene transfection for optimizing effector cell functions and for targeting gene products into tumor metastases

Fluorescently labeled, adoptively transferred interleukin (IL)-2 activated natural killer (A-NK) cells have the ability to selectively accumulate within established pulmonary or hepatic metastases, binding to tumor cells and/or to microvascular endothelial cells. A-NK cells have also been shown to exert antimetastatic therapy in animal models and in the clinic. Transfection of genes for cytokines or possibly other molecules has the potential to improve the therapeutic potency and efficacy of the effector cells. Gene transfection to induce autocrine production of IL-2 and/or other cytokines is expected to augment their antimetastatic activities, while avoiding toxicity from systemic administration of high doses of cytokines. An alternative or complementary strategy for gene therapy is to transfect A-NK cells with genes for cytotoxic molecules, to selectively target them to metastatic sites.

Sensorineural hearing loss from quinolinic acid: a neurotoxin in middle ear effusions

Quinolinic acid (QUIN) is an endogenous metabolite that exerts a neurotoxic effect by binding to specific neuronal receptors. Studies involving a broad spectrum of infectious and inflammatory central nervous system diseases have suggested a role for QUIN in causing neuronal injury. Since there is evidence for presence of the QUIN receptor in mammalian cochleas, QUIN was measured in middle ear effusions (MEEs). Gas chromatography/mass spectrometry detected QUIN in each of 65 diluted human MEEs, with a mean of 482 +/- 75 (SEM) nmol/L and a range from 15 to 2667 nmol/L. QUIN was also detected in each of 197 chinchilla MEEs from five different models of otitis media, with a mean of 10.6 +/- 1.3 (SEM) mumol/L and a range from 0.23 to 146.0 mumol/L (corrected for dilution). To determine whether QUIN causes sensorineural hearing loss (SNHL), QUIN solutions were placed on round window membranes (RWM) for 20 to 240 minutes, in 20 chinchillas. SNHL was detected by electrocochleography in QUIN-exposed animals, but not in saline controls. We conclude that QUIN is present in MEEs and that QUIN in the middle ear has the potential to cross the RWM and cause sensorineural hearing loss, possibly by binding to specific neuronal receptors in mammalian cochleas.

Expression and function of CD7 molecule on human natural killer cells

The CD7 molecule, one of the earliest T-lymphocyte Ag expressed during ontogeny, has recently been demonstrated to facilitate activation of T cells and to preferentially activate TCR-gamma/delta + subset of T cells. The CD7 Ag is also expressed on human NK cells, but its function has not been determined. In this study, expression and function of CD7 Ag on highly enriched NK cells (94 +/- 3% mean +/- SD, n = 12) obtained by negative selection from peripheral blood of normal donors were investigated. The CD7 Ag was found to be expressed at a significantly (p < 0.002) higher level on fresh NK cells than on IL-2-activated, NK cells. CD7 on human NK cells was found to be a signal-transducing molecule with a rapid increase in cytoplasmic free calcium observed on binding of anti-CD7 mAb to the surface of NK cells. Cross-linking of CD7 induced expression of surface activation molecules such as CD25, CD71, HLA-DR, CD69, and CD54. Activation by anti-CD7 mAb cross-linked to plastic or through goat anti-mouse Ig also induced a variety of NK cell functions: it stimulated secretion of IFN-gamma, led to proliferation of NK cells, as measured by [3H]thymidine incorporation, and significantly enhanced cytotoxicity of NK cells against K562 targets (p < 0.03). However, CD7 on NK cells did not seem to transduce a lytic signal, because it neither mediated redirected killing of Fc gamma R+ murine mastocytoma P815 cells nor triggered lysis of a hybridoma expressing the antibody in a membrane-bound form. CD7 molecules appeared to have a regulatory role in adhesion of NK cells to fibronectin, because cross-linking of CD7 on resting NK cells significantly augmented their adhesion to fibronectin-coated plastic surfaces. However, this induced adhesion was not associated with increased expression of beta 1-integrins on NK cells. Thus, CD7-mediated signals appear to augment function of adhesion molecules on NK cells, which may be involved in NK cell activation by providing both anchorage and costimulatory triggering.

Expression and function of CD7 molecule on human natural killer cells

The CD7 molecule, one of the earliest T-lymphocyte Ag expressed during ontogeny, has recently been demonstrated to facilitate activation of T cells and to preferentially activate TCR-gamma/delta + subset of T cells. The CD7 Ag is also expressed on human NK cells, but its function has not been determined. In this study, expression and function of CD7 Ag on highly enriched NK cells (94 +/- 3% mean +/- SD, n = 12) obtained by negative selection from peripheral blood of normal donors were investigated. The CD7 Ag was found to be expressed at a significantly (p &lt; 0.002) higher level on fresh NK cells than on IL-2-activated, NK cells. CD7 on human NK cells was found to be a signal-transducing molecule with a rapid increase in cytoplasmic free calcium observed on binding of anti-CD7 mAb to the surface of NK cells. Cross-linking of CD7 induced expression of surface activation molecules such as CD25, CD71, HLA-DR, CD69, and CD54. Activation by anti-CD7 mAb cross-linked to plastic or through goat anti-mouse Ig also induced a variety of NK cell functions: it stimulated secretion of IFN-gamma, led to proliferation of NK cells, as measured by [3H]thymidine incorporation, and significantly enhanced cytotoxicity of NK cells against K562 targets (p &lt; 0.03). However, CD7 on NK cells did not seem to transduce a lytic signal, because it neither mediated redirected killing of Fc gamma R+ murine mastocytoma P815 cells nor triggered lysis of a hybridoma expressing the antibody in a membrane-bound form. CD7 molecules appeared to have a regulatory role in adhesion of NK cells to fibronectin, because cross-linking of CD7 on resting NK cells significantly augmented their adhesion to fibronectin-coated plastic surfaces. However, this induced adhesion was not associated with increased expression of beta 1-integrins on NK cells. Thus, CD7-mediated signals appear to augment function of adhesion molecules on NK cells, which may be involved in NK cell activation by providing both anchorage and costimulatory triggering.

A phase I study of subcutaneous recombinant interleukin-2 in patients with advanced HIV disease while on zidovudine

OBJECTIVE

A Phase I study of subcutaneous recombinant interleukin-2 (rIL-2).

DESIGN

Sixteen patients with advanced HIV infection receiving 600-1200 mg zidovudine per day were divided into three groups, which received sequentially 0.2 x 10(6), 0.7 x 10(6) or 2 x 10(6) units/m2 per day of rIL-2 subcutaneously 5 consecutive days.

SETTING

Five-day admission to an academic tertiary care hospital.

PATIENTS, PARTICIPANTS

Sixteen unblinded, non-randomized volunteers.

INTERVENTIONS

Subcutaneous rIL-2.

MAIN OUTCOME MEASURES

Tolerance, toxicity, hematologic, immunologic and antiviral responses.

RESULTS

rIL-2 was well-tolerated at the highest dosage, except in two patients who developed significant lymphopenia by the second day of rIL-2 administration, with rebound within 48 h after rIL-2 therapy. The number of eosinophils, CD4+ and CD8+ cells, and percentage of CD16+ (natural killer) cells, remained elevated above baseline for up to 10 weeks. Circulating rIL-2 receptor levels increased transiently during and immediately following rIL-2 administration. A twofold increase in natural killer cell activity against uninfected and HIV-infected targets was observed, but did not persist beyond 10 weeks following rIL-2 administration. There was a transient decrease in blastogenesis to phytohemagglutinin of patients receiving the highest dose of r-IL-2, but no significant change in viral burden.

CONCLUSIONS

Subcutaneous rIL-2 in advanced HIV-infected patients on zidovudine was tolerated with side-effects similar to intravenous IL-2.

Differential effects of IL12 and IL2 on expression and function of cellular adhesion molecules on purified human natural killer cells

Accessory functions of cellular adhesion molecules (CAM) in activation, adhesion, migration, and cytotoxicity of natural killer (NK) cells are partly dependent on activation by cytokines. We studied effects of interleukin 12 (IL12) on expression and function of adhesion molecules on human NK cells and compared them to the effects mediated by IL2. Target binding of NK cells was significantly increased by IL12, leading to an increased level of conjugate formation with K562 target cells as well as enhanced binding to tumor monolayers. IL12 also induced significant levels of cytotoxicity against fresh tumor cell targets in purified human NK cells. IL12 significantly enhanced adhesion and subsequent migration of NK cells through 3-microns-pore-size polycarbonate filters. However, IL2 was a more potent activator of these functions, which have been shown to be partly mediated by CD2, CD58, beta 2 integrins, and ICAM-1. As assessed by flow cytometry, IL12 also induced significant up-regulation in the proportion or mean fluorescence intensity of NK cells positive for the following activation markers and adhesion molecules: CD25, HLA-DR, CD69, CD71, CD56, CD2, and CD54. Among the beta 2 integrins, IL12 selectively increased expression of CD11a on NK cells, although to a significantly lower level than that induced by IL2. IL12 had different in vitro effects than IL2 on expression and function of the beta 1 integrins. Whereas IL2 induced marked up-regulation in expression of the beta 1 integrins, CD49b, -c, -d, and -e, IL12 had no demonstrable effect over a wide range of concentrations. In addition, while IL2-activated NK cells showed significantly increased integrin-dependent adhesion to fibronectin- or laminin-coated plates, IL12-activated cells were less adherent to fibronectin and were unchanged in their adherence to laminin. Our data demonstrate that IL12 is involved in interactions of NK cells with fresh or cultured tumor cell targets, biologic substrates, or extracellular matrix molecules. Although the magnitude of its in vitro effects on adhesion-dependent functions of NK cells was significantly smaller than that of IL2, lower doses of IL12 were required to up-regulate functions of CAM, and this may be an attractive feature of IL12 as a potential therapeutic cytokine.

Evidence for local and systemic activation of immune cells by peritumoral injections of interleukin 2 in patients with advanced squamous cell carcinoma of the head and neck

Interleukin 2 (IL2) was injected peritumorally and intranodally in 36 patients with unresectable squamous cell carcinoma of the head and neck enrolled in an Eastern Cooperative Oncology Group-sponsored phase Ib trial (EST P-Z388). Groups of 6 patients received escalating doses(200, 2 x 10(3), 2 x 10(4), 2 x 10(5), 2 x 10(6), and 4 x 10(6) units) of IL2 daily 5 times/week for 2 weeks. Tumor biopsies were obtained before and after IL2 therapy. Tumor tissue was provided for histology, and the remaining fresh tissue was divided for snap-freezing in -75 degrees C and for separation of tumor-infiltrating lymphocytes (TIL) and tumor cells. Immunophenotyping of TIL performed on cryostat sections of paired pre- and post-IL2 biopsy tissues showed increases after IL2 therapy in the number of T-cells (P = 0.005), natural killer (NK; CD16+) cells (P = 0.0001), CD25+ cells (P = 0.004), and HLA-DR+ cells (P = 0.001) accumulating in the tumor stroma. In the tumor parenchyma, NK cells (P = 0.0001) and HLA-DR+ cells (P = 0.003) were increased after IL2 therapy. The T:NK cell ratios in the tumor stroma and parenchyma were decreased after therapy, suggesting selective accumulation of NK cells. By flow cytometry, TIL recovered from post-IL2 biopsy tissues were enriched (P < 0.05) in CD3-CD56+ (NK) cells. In situ hybridization with [35S] cDNA probes for cytokines and IL2 receptors indicated that the numbers of cells expressing mRNA for IL2, tumor necrosis factor alpha, IL1-beta, gamma-interferon, transforming growth factor beta, and IL2 receptor p55 or p70 were increased in post-IL2 biopsy tissues as compared to pre-IL2 tissues. Cytolytic activity of TIL isolated from post-IL2 tissues was also increased, as determined in 4-h 51Cr release assays against K562 targets (12 +/- 3 mean lytic units/10(7) cells +/- SEM pre-IL2 versus 46 +/- 13 post-IL2; n = 16) and against autologous tumor (13 +/- 8 versus 68 +/- 26; n = 9). Fresh TIL of one clinical responder showed relatively high levels (195 lytic units) of autotumor cytotoxicity after IL2 therapy versus no activity prior to therapy. In the blood, NK and lymphokine-activated killer cell activity, and percentages of CD3-CD56+ NK cells and of activated (CD25+) T-lymphocytes were increased for all doses of IL2.(ABSTRACT TRUNCATED AT 400 WORDS)