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Biomedical subjects

D J McKean

Publications and source records attributed to D J McKean.

At least 19 recordsLinked to original sources

A reproducible method for the enumeration of functional (cytokine producing) versus non-functional peptide-specific cytotoxic T lymphocytes in human peripheral blood.

One of the most difficult laboratory challenges in the field of therapeutic cancer vaccines has been the development of uncomplicated/reproducible methods for the quantification of vaccine immunization efficacy in peripheral blood of cancer patients. Existing methods are limited by lack of functional information (tetramers), difficulties with standardization/reproducibility [enzyme-linked immunosorbent spot (ELISPOT)] and reliance on endogenous (sample-specific) antigen presentation (cytokine flow cytometry). Herein we present a reproducible method utilizing an artificial antigen-presenting cell platform for flow cytometry-based quantification of the frequency and activation status of peptide-specific cytotoxic T lymphocytes. The methodology [currently presented for cytomegalovirus human leucocyte antigen (HLA)-A2 cognant peptide antigens] allows simultaneous ex vivo quantification of activated (cytokine-producing) and inactive tetramer-positive T cells following HLA class I/peptide/CD28 stimulation independent of endogenous antigen presentation. The simplicity and reliability of the assay provide for high-throughput applications and automation. The utility and application of this method are discussed.

Antigen-Presenting Cells↗

Dendritic cell modulation by 1alpha,25 dihydroxyvitamin D3 and its analogs: a vitamin D receptor-dependent pathway that promotes a persistent state of immaturity in vitro and in vivo.

Dendritic cells (DCs) play a central role in regulating immune activation and responses to self. DC maturation is central to the outcome of antigen presentation to T cells. Maturation of DCs is inhibited by physiological levels of 1alpha,25 dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)] and a related analog, 1alpha,25(OH)(2)-16-ene-23-yne-26,27-hexafluoro-19-nor-vitamin D(3) (D(3) analog). Conditioning of bone marrow cultures with 10(-10) M D(3) analog resulted in accumulation of immature DCs with reduced IL-12 secretion and without induction of transforming growth factor beta1. These DCs retained an immature phenotype after withdrawal of D(3) analog and exhibited blunted responses to maturing stimuli (CD40 ligation, macrophage products, or lipopolysaccharide). Resistance to maturation depended on the presence of the 1alpha,25(OH)(2)D(3) receptor (VDR). In an in vivo model of DC-mediated antigen-specific sensitization, D(3) analog-conditioned DCs failed to sensitize and, instead, promoted prolonged survival of subsequent skin grafts expressing the same antigen. To investigate the physiologic significance of 1alpha,25(OH)(2)D(3)/VDR-mediated modulation of DC maturity we analyzed DC populations from mice lacking VDR. Compared with wild-type animals, VDR-deficient mice had hypertrophy of subcutaneous lymph nodes and an increase in mature DCs in lymph nodes but not spleen. We conclude that 1alpha,25(OH)(2)D(3)/VDR mediates physiologically relevant inhibition of DC maturity that is resistant to maturational stimuli and modulates antigen-specific immune responses in vivo.

Animals↗

Maturation versus death of developing double-positive thymocytes reflects competing effects on Bcl-2 expression and can be regulated by the intensity of CD28 costimulation.

Immature double-positive (DP) thymocytes mature into CD4(+)CD8(-) cells in response to coengagement of TCR with any of a variety of cell surface "coinducer" receptors, including CD2. In contrast, DP thymocytes are signaled to undergo apoptosis by coengagement of TCR with CD28 costimulatory receptors, but the molecular basis for DP thymocyte apoptosis by TCR plus CD28 coengagement is not known. In the present study, we report that TCR plus CD28 coengagement does not invariably induce DP thymocyte apoptosis but, depending on the intensity of CD28 costimulation, can induce DP thymocyte maturation. We demonstrate that distinct but interacting signal transduction pathways mediate DP thymocyte maturation signals and DP thymocyte apoptotic signals. Specifically, DP maturation signals are transduced by the extracellular signal-related kinase (ERK)/mitogen-activated protein kinase (MAPK) pathway and up-regulate expression of the antiapoptotic protein Bcl-2. In contrast, the apoptotic response stimulated by CD28 costimulatory signals is mediated by ERK/MAPK-independent pathways. Importantly, when TCR-activated thymocytes are simultaneously coengaged by both CD28 and CD2 receptors, CD28 signals can inhibit ERK/MAPK-dependent Bcl-2 protein up-regulation. Thus, there is cross-talk between the signal transduction pathways that transduce apoptotic and maturation responses, enabling CD28-initiated signal transduction pathways to both stimulate DP thymocyte apoptosis and also negatively regulate maturation responses initiated by TCR plus CD2 coengagement.

Animals↗

The analysis of costimulatory receptor signaling cascades in normal T lymphocytes using in vitro gene transfer and reporter gene analysis.

Ligation of the antigen receptor and costimulatory receptors on the surface of T lymphocytes initiates intracellular signals that regulate cell-cycle progression and cell differentiation. To effectively manipulate the activation of T cells for immunotherapeutic applications, it will be important to understand how these signaling pathways are integrated to control specific gene transcription events. Here we describe a novel transient transfection procedure that efficiently introduces DNA into non-dividing normal human and murine T lymphocytes while maintaining high cell viability. Using this technique, reporter genes can be introduced to characterize intracellular signaling pathways that regulate specific gene transcription events in normal T-lymphocyte populations. We show that the CD28 receptor can be differentially coupled to downstream signaling pathways in different T-lymphocyte populations. In addition, we demonstrate that a gene encoding a tagged constitutively active mitogen-activated kinase kinase-1 protein can be transfected and rapidly expressed to regulate the expression of Bcl-2 in normal thymocytes.

Animals↗

Potent inhibition of dendritic cell differentiation and maturation by vitamin D analogs.

We show that the immunosuppressive effects of 1alpha, 25-dihydroxyvitamin D(3) (1alpha,25(OH)(2)D(3)) are due, in part, to inhibition of the T cell stimulatory functions of dendritic cells (DCs). Addition of 10(-12) and 10(-8) M 1alpha,25(OH)(2)D(3) to murine DC cultures resulted in a concentration-dependent reduction in levels of class II MHC and the co-stimulatory ligands B7-1, B7-2, and CD40 without affecting the number of DCs generated. Higher concentrations of 1alpha,25(OH)(2)D(3) reduced DC yield. The capacity of DCs to induce proliferation of purified allogeneic T cells was reduced by 1alpha,25(OH)(2)D(3). The vitamin D(3) analog, 1alpha,25(OH)(2)-16-ene-23-yne-26,27-hexafluoro-19-nor -D(3), exerted identical effects at 100-fold lower concentrations. Inhibition of DC maturation and stimulatory function was absent in cultures from mice genetically lacking vitamin D receptors (VDR). Vitamin D analogs effectively reduce DC function via VDR-dependent pathways.

Animals↗

Inhibition of interleukin-1-stimulated NF-kappaB RelA/p65 phosphorylation by mesalamine is accompanied by decreased transcriptional activity.

Nuclear factor kappaB (NF-kappaB) is an inducible transcription factor that regulates genes important in immunity and inflammation. The activity of NF-kappaB is highly regulated: transcriptionally active NF-kappaB proteins are sequestered in the cytoplasm by inhibitory proteins, IkappaB. A variety of extracellular signals, including interleukin-1 (IL-1), activate NF-kappaB by inducing phosphorylation and degradation of IkappaB, allowing nuclear translocation and DNA binding of NF-kappaB. Many of the stimuli that activate NF-kappaB by inducing IkappaB degradation also cause phosphorylation of the NF-kappaB RelA (p65) polypeptide. The transactivating capacity of RelA is positively regulated by phosphorylation, suggesting that in addition to cytosolic sequestration by IkappaB, phosphorylation represents another mechanism for control of NF-kappaB activity. In this report, we demonstrate that mesalamine, an anti-inflammatory aminosalicylate, dose-dependently inhibits IL-1-stimulated NF-kappaB-dependent transcription without preventing IkappaB degradation or nuclear translocation and DNA binding of the transcriptionally active NF-kappaB proteins, RelA, c-Rel, or RelB. Mesalamine was found to inhibit IL-1-stimulated RelA phosphorylation. These data suggest that pharmacologic modulation of the phosphorylation status of RelA regulates the transcriptional activity of NF-kappaB, independent of nuclear translocation and DNA binding. These findings highlight the importance of inducible phosphorylation of RelA in the control of NF-kappaB activity.

Base Sequence↗

Gi proteins use a novel beta gamma- and Ras-independent pathway to activate extracellular signal-regulated kinase and mobilize AP-1 transcription factors in Jurkat T lymphocytes.

Receptors coupled to pertussis toxin (PTX)-sensitive Gi proteins regulate T lymphocyte cytokine secretion, proliferation, and chemotaxis, yet little is known about the molecular mechanisms of Gi protein signaling in mammalian lymphocytes. Using the Jurkat T lymphocyte cell line, we found that a stably expressed Gi protein-coupled receptor (the delta-opioid receptor (DOR1)) stimulates MEK-1 and extracellular signal-regulated kinases 1 and 2 (ERK1 and ERK2) and transcriptional activity by an ERK target, Elk-1, via a mechanism requiring a PTX-sensitive Gi protein. Levels of beta-adrenergic receptor kinase-1 C-terminal fragment that inhibited signaling by Gi protein beta gamma subunits in these cells had no effect on DOR1 stimulation of either MEK-1- or Elk-1-dependent transcription, indicating that this pathway is independent of beta gamma. Analysis of this betagamma-independent pathway indicates a role for a herbimycin A-sensitive tyrosine kinase. Unlike beta gamma-mediated pathways, the beta gamma-independent pathway was insensitive to RasN17, inhibitors of phosphatidylinositol 3-kinase (PI 3-kinase), and constitutive PI 3-kinase activity. The beta gamma-independent pathway regulates downstream events, since blocking it abrogated both Elk-1-dependent transcription and mobilization of the mitogenic transcription factor, AP-1, in response to DOR1 signaling. These results characterize a novel, Ras- and PI 3kinase-independent pathway for ERK activation by Gi protein signaling that is distinct from ERK activation by beta gamma and may therefore be mediated by the alphai subunit.

Benzoquinones↗

Signaling through delta opioid receptors on murine splenic T cells and stably transfected Jurkat cells.

beta-Endorphin (beta-EP) and delta opioid receptor (DOR) agonists affect immune functions such as lymphocyte chemotaxis, proliferation, and cytokine production. Recent studies indicate that both neuronal DOR and novel G-protein-coupled receptors with high affinity for beta-EP and DOR agonists are expressed by mononuclear cells. In addition, proenkephalin A mRNA and enkephalin-related peptides are expressed by lymphocytes. These investigations were conducted to identify signal transduction pathways that mediate the effects of beta-EP and DOR agonists on T cells. Calcium mobilization was studied because it is central to T-cell activation initiated by antigen presentation to the T-cell receptor (TCR). Using the calcium-sensitive dye Fluo-3 and flow cytofluorometry to determine the concentration of free intracellular calcium, physiological concentrations of beta-EP were shown to enhance concanvalin. A (con A)-stimulated calcium mobilization by murine splenic T cells (p < 0.01). The DOR antagonist, naltrindole, inhibited this, whereas CTAP, a selective mu OR antagonist, was ineffective. In addition, N-Ac-beta-EP and the mu OR agonist DAMGO, failed to mimic the effects of beta-EP. Although it was less potent than beta-EP, DADLE, a DOR agonist, also enhanced Con-A-induced calcium mobilization (p < 0.01). A DOR-transfected human T-cell line (DOR-Jul.1) was developed to study signal transduction. Both DADLE and the selective DOR agonist, deltorphin, rapidly increased intracellular free calcium concentrations; ED50s were 10(-9) M. Pertussis toxin prevented the response, and EGTA significantly reduced it. In addition, DADLE inhibited forskolin-stimulated cAMP production (ED50: 10(-11) M). These findings with normal splenic T cells and DOR-transfected T-cell line indicate that beta-EP and DOR agonists affect calcium mobilization. This is likely to modulate downstream pathways that regulate T-cell activation and function.

Animals↗

Mechanism responsible for T-cell antigen receptor- and CD28- or interleukin 1 (IL-1) receptor-initiated regulation of IL-2 gene expression by NF-kappaB.

Initiation of the T-helper lymphocyte activation program is regulated through the T-cell receptor (TCR) and costimulatory receptors. Analysis of TCR and either anti-CD28- or interleukin 1 (IL-1)-mediated activation of the IL-2 promoter shows that costimulatory signals augment promoter activity through NF-kappaB sites. This study comparatively evaluates the mechanisms whereby signals initiated from the TCR and these two costimulatory receptors converge to synergistically increase NF-kappaB transcriptional activity. IL-1 alone stimulates an acute but transient NF-kappaB nuclear localization and a suboptimal NF-kappaB transcriptional response. In contrast, anti-CD3-anti-CD28 or anti-CD3-IL-1 synergistically stimulate prolonged NF-kappaB nuclear localization and NF-kappaB-mediated transcription. Both TCR- and costimulatory receptor-initiated synergistic NF-kappaB responses result from prolonging high rates of cytosolic IkappaB degradation during the second phase of the biphasic NF-kappaB nuclear localization. However, in contrast to previous reports, prolonged nuclear localization of NF-kappaB complexes is not necessarily associated with long-term depletion of IkappaBbeta. In response to either costimulus, c-Rel selectively translocated to the nucleus as a result of induced c-Rel expression and the continued production of c-Rel-IkappaBalpha complexes, which turn over rapidly due to the high rate of IkappaBalpha degradation in the cytosol during the second phase of the response. In contrast, IkappaBbeta is nearly completely degraded during the acute response to either IL-1 or anti-CD3-IL-1 while anti-CD3-anti-CD28 stimulates only a partial reduction (35 to 40%) in cytosolic IkappaBbeta. Cyclosporine (CsA), which inhibits stimulus-induced NF-kappaB transcriptional activity, selectively inhibits the stimulus-induced c-Rel nuclear localization and the rapid formation and degradation of c-Rel-IkappaBalpha complexes in the cytosol. CsA also inhibits both the prolonged, high rate of IkappaBalpha degradation and the lower level of IkappaBbeta turnover during the second phase of the activation response. Together, these results suggest a mechanism by which signals from the T-cell antigen receptor and either CD28 or IL-1 synergistically regulate IL-2 gene transcription by modulating NF-kappaB nuclear translocation.

Animals↗

Delta-opioid receptors expressed by Jurkat T cells enhance IL-2 secretion by increasing AP-1 complexes and activity of the NF-AT/AP-1-binding promoter element.

Recent molecular evidence points to transient and/or stage-specific expression of delta- and kappa-opioid receptors by thymic and peripheral T lymphocytes. Since medical treatments or stress commonly increase opioid levels, it is important to understand the mechanisms by which opioids affect T lymphocyte functions. We therefore created and studied a T cell line expressing the cloned delta-opioid receptor (DOR1). DOR1 ligation by a specific DOR1 agonist, deltorphin, augmented IL-2 secretion by synergizing with signals from TCR-CD3 and CD28. Reporter gene constructs were used to map this effect of deltorphin to the AP-1- and NF-AT/AP-1-binding sites of the IL-2 promoter. Although DOR1 signaling increased [Ca2+]i, deltorphin enhanced transcriptional activity of the NF-AT/AP-1-binding site via a mechanism independent of calcineurin and distinct from the effects of elevated [Ca2+]i. Deltorphin also increased accumulation of AP-1 transcription factor complexes, suggesting that DOR1 augments IL-2 secretion by increasing the AP-1 component of the NF-AT/AP-1 transcription factor. These results advance the molecular understanding of opioid effects on lymphocytes, and in addition, demonstrate regulation of IL-2 synthesis and secretion by the novel mechanism of receptor-mediated AP-1 induction.

Base Sequence↗

Dual signal transduction through delta opioid receptors in a transfected human T-cell line.

Opiates are known to function as immunomodulators, in part by effects on T cells. However, the signal transduction pathways mediating the effects of opiates on T cells are largely undefined. To determine whether pathways that regulate free intracellular calcium ([Ca2+]i) and/or cAMP are affected by opiates acting through delta-type opioid receptors (DORs), a cDNA encoding the neuronal DOR was expressed in a stably transfected Jurkat T-cell line. The DOR agonists, deltorphin and [D-Ala2, D-Leu5]-enkephalin (DADLE), elevated [Ca2+]i, measured by flow cytofluorometry using the calcium-sensitive dye, Fluo-3. At concentrations from 10(-11)-10(-7) M, both agonists increased [Ca2+]i from 60 nM to peak concentrations of 400 nM in a dose-dependent manner within 30 sec (ED50 of approximately 5 x 10(-9) M). Naltrindole, a selective DOR antagonist, abolished the increase in [Ca2+]i, and pretreatment with pertussis toxin was also effective. To assess the role of extracellular calcium, cells were pretreated with EGTA, which reduced the initial deltorphin-induced elevation of [Ca2+]i by more than 50% and eliminated the second phase of calcium mobilization. Additionally, the effect of DADLE on forskolin-stimulated cAMP production was determined. DADLE reduced cAMP production by 70% (IC50 of approximately equal to 10(-11) M), and pertussis toxin inhibited the action of DADLE. Thus, the DOR expressed by a transfected Jurkat T-cell line is positively coupled to pathways leading to calcium mobilization and negatively coupled to adenylate cyclase. These studies identify two pertussis toxin-sensitive, G protein-mediated signaling pathways through which DOR agonists regulate the levels of intracellular messengers that modulate T-cell activation.

Adenylate Cyclase Toxin↗

Interleukin-1 signal transduction.

Interleukin-1 (IL-1) is primarily an inflammatory cytokine, although it is capable of mediating a wide variety of effects on many different cell types. Nearly every known signal transduction pathway has been reported to be activated in response to IL-1. However, the significance of many of these signaling events is unclear, due to the use of different and sometimes unique cell lines in studying IL-1-initiated signal transduction. Complicating matters further is the lack of association in many studies between identified IL-1-induced signals and subsequent biological responses. In this article, we review what is known about IL-1 receptor signaling and, whenever possible, correlate signaling events to biological responses.

Animals↗

Aglycosylated and phosphatidylinositol-anchored MHC class I molecules are associated with calnexin. Evidence implicating the class I-connecting peptide segment in calnexin association.

The endoplasmic reticulum resident protein calnexin interacts with several glycoproteins including class I MHC molecules. Calnexin is thought to retain free class I heavy chains and/or promote their folding and assembly with beta 2-microglobulin and peptide ligand. Whereas with other glycoproteins, Asn-linked glycans seem to be involved in calnexin association, with class I molecules the transmembrane region has been implicated. To critically define the structures on class I molecules that determine their interaction with calnexin, we have studied carbohydrate-deficient and transmembrane-variant class I molecules. Carbohydrate-deficient class I molecules were found to accumulate intracellularly in an open, non-beta 2-microglobulin-associated conformation. However, open as well as conformed class I molecules showed significant calnexin association whether they were aglycosylated or fully glycosylated. Thus, carbohydrate moieties may be necessary for efficient class I folding, but are not required for calnexin association. Calnexin was also found associated with a soluble class I molecule that has a truncated transmembrane segment, demonstrating that membrane attachment of class I is not required for interaction with calnexin. Finally, two isoforms of the class Ib molecule Q7b were compared. Unexpectedly, the glycosylphosphatidylinositol-anchored Q7b isoform was found associated with calnexin, whereas the soluble Q7b isoform was not calnexin associated. These comparisons of Q7b isoforms implicate the class I-connecting peptide segment and not the transmembrane region as a site of interaction with calnexin.

Amino Acid Sequence↗

Molecular mechanisms that control expression of the B lymphocyte antigen receptor complex.

The B cell receptor for antigen (BCR) is a complex of membrane immunoglobulin (mIg) and at least two other proteins, Ig alpha (mb-1) and Ig beta (B29). This complex promotes surface expression of the BCR and acts to transduce an activation signal. We have used a system of mu heavy chain constructs transfected into murine B cell lines to probe structure-function relationships in the BCR complex. One mutant mu chain, in which two polar transmembrane residues (Tyr587, Ser588) are replaced with valine, fails to associate with Ig alpha and Ig beta and is incapable of transducing signals as a result of mIg cross-linking. This mutant is expressed on the surface at high levels when transfected into a plasmacytoma line that lacks Ig alpha, whereas wild-type mu is retained in this cell line in the endoplasmic reticulum. Pulse-chase and immunoprecipitation analyses indicate that the mutant is more rapidly released from calnexin than the wild-type mu. Further, transfection of Ig alpha into this Ig alpha-negative cell line allows release of the mu chain from calnexin and surface expression of the BCR. These results identify the transmembrane residues of mu heavy chain that control binding to calnexin and Ig alpha, and suggest that calnexin-dependent intracellular retention is an important control mechanism for expression of the BCR complex.

Animals↗

Truncated MHC class II cytoplasmic and transmembrane domains: effect on plasma membrane expression.

Plasma membrane (PM) expression of major histocompatibility complex (MHC) class II molecule is required for the interaction of antigen (Ag) presenting cells and T lymphocytes. Class II molecules composed of an alpha and a beta chain are highly polymorphic which facilitates their interaction with Ag and Ag-specific T cells. Recently, we have focused on the less polymorphic sequences of class II molecules, the transmembrane (TM) and cytoplasmic (Cy) domains, in an attempt to understand what their function might be. Using site-directed mutagenesis to create truncations in the TM and Cy domains of IAk's alpha or beta chain, or both, we have identified some of the sequence requirements for efficient surface expression of I-Ak molecules. Ak beta TM mutants that are not expressed at the PM are not transported past the medial-Golgi as indicated by in situ staining and Western blot analysis of endoglycosidase-H-treated immunoprecipitates. The lack of transport of TM class II mutants is not due to lack of association with the invariant chain (Ii). Class II molecules with Cy domain truncations in both chains are not efficiently transported to the PM and also have a percentage of molecules that are endoglycosidase-H sensitive. In situ staining of class II in cells expressing Cy domain truncated class II molecules revealed a discrete vesicular pattern compared to the staining of transfectants that expressed wildtype class II molecules. The immunofluorescence data along with the endoglycosidase-H data indicate the Cy domains are required for efficient transport. Immunoprecipitation studies using a panel of I-Ak conformation-specific antibodies revealed that the truncation of the Cy domains of both chains did not effect the conformation of class II. However, further truncation of the Ak beta chain into the TM domain resulted in lack of transport past the ER/medial-Golgi and diminished expression (stability) of mutant class II proteins within the cells. The alpha/beta chains of the TM mutants that did associate bound a panel of conformation sensitive antibodies except for one, 3F12. We conclude that the Cy domain of the alpha and beta chains of MHC class II, as well as sequences in the TM domains of the Ak beta chain are required for efficient class II PM expression. The reason for the lack of PM expression of TM mutants may be the inability to assess a transport competent conformation as defined by the 3F12-specific epitope, while truncation of the Ak alpha Cy domains is proposed to prevent complete masking of the ER retention sequence of the Ii chain.

Animals↗

IL-1 receptor and TCR signals synergize to activate NF-kappa B-mediated gene transcription.

Previous studies have demonstrated that IL-1 receptor (IL-1R)- and TCR-initiated signals can interact synergistically to increase the rate of transcription of several lymphokine and lymphokine receptor genes during the competence phase of the activation program in T helper lymphocytes. In this report we describe how signals initiated through the type I IL-1R interact with signals from the antigen receptor to synergistically augment the transactivating properties of NF-kappa B. The synergistic antigen receptor initiated signals are mediated through protein kinase C because they can be mimicked by the phorbol ester, 12-O-tetradecanoylphorbol-13-acetate, but not with calcium ionophores; and are staurosporine sensitive but cyclosporine resistant. Gel shift analyses demonstrate that NF-kappa B nuclear translocation is stimulated primarily by IL-1 rather than by antigen receptor signals. Western blot and phosphorylation analyses demonstrate that the synergistic effect on NF-kappa B functional activity is independent of I kappa B alpha (MAD3)-NF-kappa B dissociation in the cytosol and is not associated with I kappa B nuclear translocation. The IL-1-induced NF-kappa B DNA nuclear localization is transient and can be prolonged either by an antigen receptor-initiated signal or by inhibiting protein synthesis. These results suggest that IL-1 induces both NF-kappa B nuclear translocation and the synthesis of a protein(s) responsible for terminating NF-kappa B-DNA interaction in the nucleus. Antigen receptor signals prolong NF-kappa B-DNA interaction, probably by functionally antagonizing the IL-1-induced synthesis of a protein(s) responsible for the transient NF-kappa B-DNA interaction and consequently synergistically enhance IL-1-induced NF-kappa B-dependent gene transcription.

Alkaloids↗

Tumor localization and therapeutic potential of an antitumor-anti-CD3 heteroconjugate antibody in human renal cell carcinoma xenograft models.

A heteroconjugate (HC) antibody, constructed with the monoclonal antibody (MoAB) Dal K29 to human renal cell carcinoma (RCC) and an anti-CD3 MoAb, could induce a very high level of lysis of human RCC cells when incubated with human peripheral blood lymphocytes (PBL) in vitro (Kerr et al., 1990, J. Immunol., 144, 4060-4067). We now report that this HC antibody selectively localizes in RCC xenografts in nude mice and could inhibit RCC in an ascites tumor xenograft model when administered intraperitoneally together with PBL.

Animals↗