T cells engrafted with a recombinant anti-CD30 receptor target autologous CD30(+) cutaneous lymphoma cells.

T cells can be directed to antigen-specific, MHC-independent target cell lysis by grafting with a recombinant receptor with antibody-like specificity. Here, we asked whether T cells from the peripheral blood of a patient with cutaneous T cell lymphoma can be recruited for an immune response against autologous tumor cells. Lymphoma cells with a CD3(-) CD4(+) CD30(+) phenotype and clonal TCR-Vbeta7 rearrangement were isolated from a cutaneous lesion. The lymphoma lesion additionally harbored CD3(+) CD25(+) activated normal T cells despite ongoing tumor progression. Peripheral blood-derived T cells from the lymphoma patient were retrovirally engrafted with a recombinant anti-CD30-scFv-gamma receptor. Upon cocultivation with autologous CD30(+)lymphoma cells, grafted T cells increase IFN-gamma secretion and lyse specifically lymphoma cells with high efficiency, even at an effector to target cell ratio of as low as 1:20. Our data demonstrate that the recombinant anti-CD30-gamma receptor overcomes T cell tolerance for tumor cells and directs T cells specifically against autologous lymphoma cells.     

T cell activation by recombinant FcepsilonRI gamma-chain immune receptors: an extracellular spacer domain impairs antigen-dependent T cell activation but not antigen recognition

T cells can be endowed with antigen specificity by grafting with a chimeric receptor consisting of an extracellular antigen binding moiety (scFv) derived from an antibody and an intracellular signaling domain. Conflicting data exist on the impact of an extracellular spacer domain between the antigen binding and the signaling domain with respect to cellular activation. Here, we recorded conjugate formation and antigen-driven cellular activation of T cells grafted with receptor molecules that contain the same antigen binding site (anti-CD30 HRS3-scFv) and signaling domain (FcepsilonRI gamma-chain), however, with and without an IgG1 CH2CH3 (Fc) spacer domain between the scFv and transmembrane moiety. Receptors of both configurations mediate equally efficient conjugate formation between receptor grafted T cells and antigen-positive target cells. Specific signaling by the spacer containing receptor, however, is blocked by five- to 10-fold lower concentrations of soluble antigen than by the spacer-less receptor indicating a higher avidity of the spacer containing receptor to soluble antigen. In contrast, cellular activation upon binding to antigen-positive cells is mediated more efficiently by the spacer-less receptor. This demonstrates that the extracellular spacer domain impairs antigen-dependent cellular activation by the chimeric immune receptor, but not intercellular conjugate formation.     

Anti-Tumor CC49-zeta CD4 T cells possess both cytolytic and helper functions

The authors report that the nature of the T-cell-receptor--derived signal in normal CD4+ T cells can induce interleukin-2 (IL-2) secretion or perforin-mediated cytolytic activity. Normal human T cells were genetically modified to express the tumor antigen specific chimeric immune receptor, CC49-zeta. The CC49-zeta chimeric immune receptor is comprised of the intracellular signaling domains of the TCR CD3zeta protein fused to the single chain scFv of the humanized CC49 antibody, which binds the pan-adenocarcinoma tumor antigen TAG-72. Patient-specific T cells genetically modified to express the CC49-zeta receptor have been used in patients with colon cancer. The authors report that both CD4 and CD8 T cells expressing the CC49-zeta receptor mediated the major histocompatibility complex-unrestricted lysis of TAG-72--expressing tumor cells with comparable efficiency. However, although the CC49-zeta receptor mediated target cell lysis, it did not support the production of IL-2, even in the presence of CD28 stimulation. Robust IL-2 secretion and T-cell proliferation were observed when the same CD4 CC49-zeta T cells were stimulated through the CD28 receptor and endogenous T-cell receptor. These results indicate that CD4 T lymphocytes possess the capacity to act as both cytolytic and helper T cells and that this difference in effector function is controlled by the nature of the T-Cell receptor--derived signals.     

Requirements for the construction of antibody heterodimers for the direction of lysis of tumors by human T cells.

We constructed a series of MAb heterodimers consisting of the J5 (anti-common acute lymphoblastic leukemia antigen [CALLA]) antibody and antibodies to a variety of structures present on the surface of activated human T cells, including CD3 antigen (T cell receptor-associated glycoproteins), CD2 antigen (T11/E-rosette receptor), CD25 antigen (IL-2 receptor), and the transferrin receptor. We tested the ability of these heterodimers to direct a CD2 + CD3 + CD8 + CD4 - CD25 + transferrin receptor + MHC-restricted human cytolytic T lymphocyte (CTL) clone to lyse a CALLA + human tumor in vitro. Only heterodimers containing an anti-CD3 antibody or activating antibodies to CD2 could direct the clone to lyse these human tumor targets, even when the clone was additionally activated with anti-CD3 or anti-CD2 antibodies. Our findings may have implications in the design of strategies for the use of such reagents in the treatment of human neoplasia.     

CTLA4 blockade maximizes antitumor T-cell activation by dendritic cells presenting idiotype protein or opsonized anti-CD20 antibody-coated lymphoma cells

CTLA4 is a negative regulator of the costimulatory signals induced by the interaction of CD28 on T cells and B7 on dendritic cells (DCs). Antibodies (Abs) against CTLA4 can block its function and increase the activation of T cells primed to recognize antigens. The effect of CTLA4 blockade on the cross-presentation of tumor antigens by DCs to T cells was examined. Immune T cells and DC precursors were collected from patients receiving idiotype protein-pulsed DC vaccines, exposed to antigen, and examined for antitumor activity by measuring intracellular cytokine production by FACS. Idiotype-specific activation occurred in CD8+ and CD4+ T-cell populations and was up to 58 fold higher with CTLA4 blockade. These T cells could be expanded quickly and maintained tumor cytolytic activity. T-cell responses to whole tumor cell-pulsed DCs were then examined. DCs contain Fc receptors and efficiently phagocytose lymphoma cells when coated with opsonizing anti-CD20 Abs. Within a few hours, DCs ingested tumor cells and labeled proteins were observed in the cytoplasm. When anti-CD20 Ab-coated tumor-pulsed DCs were used in combination with CTLA4 blockade, up to 15 fold higher activation of Id-specific CD8+ and 3 fold higher CD4+ T cells resulted. Thus, CTLA4 blockade can enhance the measurement of Ag-specific T-cell responses and the expansion of T cells for clinical studies. In addition, the combination of CTLA4 blockade and Ab targeting of tumor to DCs is an effective method for the cross-presentation of tumor cell antigens.     

A chimeric receptor that selectively targets membrane-bound carcinoembryonic antigen (mCEA) in the presence of soluble CEA.

Chimeric T cell receptors with specificity for tumor-associated antigens are successfully used to target T cells to tumor cells. The efficacy of this approach, however, is reduced by soluble antigen that is frequently present in high serum concentrations. To overcome this situation, we constructed an anti-CEA chimeric receptor whose extracellular moiety is composed of a humanized single chain antibody fragment (scFv) derived from the anti-CEA mAb BW431/26 and the CH2/CH3 constant domains of human IgG. The intracellular moiety consists of the gamma-signaling chain of the human Fc epsilon RI receptor constituting a completely humanized chimeric receptor. After transfection, the humBW431/26 scFv-CH2CH3-gamma receptor is expressed as a homodimer on the surface of MD45 T cells. Co-incubation with CEA+ tumor cells specifically activates grafted MD45 T cells indicated by IL-2 secretion and cytolytic activity against CEA+ tumor cells. Notably, the efficacy of receptor-mediated activation is not affected by soluble CEA up to 25 micrograms/ml demonstrating the usefulness of this chimeric receptor for specific cellular activation by membrane-bound CEA even in the presence of high concentrations of CEA, as found in patients during progression of the disease.     

Target antigen expression on a professional antigen-presenting cell induces superior proliferative antitumor T-cell responses via chimeric T-cell receptors

Human T cells expressing tumor antigen-specific chimeric receptors fail to sustain their growth and activation in vivo, which greatly reduces their therapeutic value. The defective proliferative response to tumor cells in vitro can partly be overcome by concomitant CD28 costimulatory signaling. We investigated whether T-cell activation via chimeric receptors (chRec) can be further improved by ligand expression on antigen-presenting cells of B-cell origin. We generated Epstein-Barr virus (EBV)-specific cytotoxic T lymphocytes (CTLs) expressing a CD19-specific chRec. These CTLs are provided with native receptor stimulation by autologous EBV-transformed B-lymphoblastoid cell lines (LCLs) but exclusively with chRec (CD19-specific) stimulation by allogeneic, human leukocyte antigen (HLA)-mismatched CD19+ LCLs. CD19zeta-transduced EBV-specific CTLs specifically lysed both allogeneic EBV targets and CD19+ tumor cells through the chRec in a major histocompatibility complex-independent manner, while maintaining their ability to recognize autologous EBV targets through the native T-cell receptor. The transduced CTLs failed to proliferate in response to CD19+ tumor targets even in the presence of CD28 costimulatory signaling. By contrast, CD19 expressed on HLA-mismatched LCL-induced T-cell activation and long-term proliferation that essentially duplicated the result from native receptor stimulation with autologous LCLs, suggesting that a deficit of costimulatory molecules on target cells in addition to CD28 is indeed responsible for inadequate chRec-mediated T-cell function. Hence, effective tumor immunotherapy may be favored if engagement of the chRec on modified T cells is complemented by interaction with multiple costimulator molecules. The use of T cells with native specificity for EBV may be one means of attaining this objective.     

c-FLIP mediates resistance of Hodgkin/Reed-Sternberg cells to death receptor-induced apoptosis

Resistance to death receptor-mediated apoptosis is supposed to be important for the deregulated growth of B cell lymphoma. Hodgkin/Reed-Sternberg (HRS) cells, the malignant cells of classical Hodgkin's lymphoma (cHL), resist CD95-induced apoptosis. Therefore, we analyzed death receptor signaling, in particular the CD95 pathway, in these cells. High level CD95 expression allowed a rapid formation of the death-inducing signaling complex (DISC) containing Fas-associated death domain-containing protein (FADD), caspase-8, caspase-10, and most importantly, cellular FADD-like interleukin 1beta-converting enzyme-inhibitory protein (c-FLIP). The immunohistochemical analysis of the DISC members revealed a strong expression of CD95 and c-FLIP overexpression in 55 out of 59 cases of cHL. FADD overexpression was detectable in several cases. Triggering of the CD95 pathway in HRS cells is indicated by the presence of CD95L in cells surrounding them as well as confocal microscopy showing c-FLIP predominantly localized at the cell membrane. Elevated c-FLIP expression in HRS cells depends on nuclear factor (NF)-kappaB. Despite expression of other NF-kappaB-dependent antiapoptotic proteins, the selective down-regulation of c-FLIP by small interfering RNA oligoribonucleotides was sufficient to sensitize HRS cells to CD95 and tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis. Therefore, c-FLIP is a key regulator of death receptor resistance in HRS cells.     

Primary polyclonal human T lymphocytes targeted to carcino-embryonic antigens and neural cell adhesion molecule tumor antigens by CD3zeta-based chimeric immune receptors

Antigen-specific T lymphocytes are attractive as potential anticancer agents. The generation of large numbers of antigen-specific T cells is possible through the use of gene therapy to express targeting receptors on the T lymphocyte. Activated T lymphocytes were transduced to express carcino-embryonic antigen or neural cell adhesion molecule targeted CD3zeta chimeric immune receptors. The chimeric receptors were expressed as homodimers and also as heterodimers with the native CD3zeta. T lymphocyte populations were expanded in the absence of selection for the modified cells and were shown to produce cytokines when cultured in the presence of immobilized purified protein antigen. These lymphocytes also responded by cytokine production and cytolytic activity when challenged with tumor-cell lines expressing the antigen recognized by the chimeric immune receptor. The cytolytic activity appears to be largely perforin mediated. Furthermore, soluble carcino-embryonic antigen did not interfere with the functional activity of the carcino-embryonic antigen-targeted lymphocytes. Long-term (5-day) stimulation of the modified lymphocytes by protein antigen resulted in reduced viability similar to that induced by anti-CD3 antibodies alone. Viability was improved by a costimulatory signal indicating that such signals may be vital in the maintenance of long-term functional activity of receptor modified T lymphocytes.     

CD28 cosignalling does not affect the activation threshold in a chimeric antigen receptor-redirected T-cell attack

Adoptive immunotherapy of cancer using chimeric antigen receptor (CAR)-engineered T cells with redirected specificity showed efficacy in recent trials. In preclinical models, 'second-generation' CARs with CD28 costimulatory domain in addition to CD3ζ performed superior in redirecting T-cell effector functions and survival. Whereas CD28 costimulation sustains physiological T-cell receptor (TCR)-CD3 activation of na?ve T cells, the impact of CD28 cosignalling on the threshold of CAR-mediated activation of pre-stimulated T cells without B7-CD28 recruitment remained unclear. Using CARs of different binding affinities, but same epitope specificity, we demonstrate that CD28 cosignalling neither lowered the antigen threshold nor the binding affinity for redirected T-cell activation. 'Affinity ceiling' above which increase in affinity does not increase T-cell activation was not altered. Accordingly, redirected tumor cell killing depended on the binding affinity but was likewise effective for CD3ζ and CD28-CD3ζ CARs. In contrast to CD3ζ, CD28-CD3ζ CAR-driven activation was not increased further by CD28-B7 engagement. However, CD28 cosignalling, which is required for interleukin-2 induction could not be replaced by high-affinity CD3ζ CAR binding or high-density antigen engagement. We conclude that CD28 CAR cosignalling does not alter the activation threshold but redirects T-cell effector functions.     

Therapeutic effects of tumor reactive CD4+ cells generated from tumor-primed lymph nodes using anti-CD3/anti-CD28 monoclonal antibodies

T-cell activation involves multiple signaling pathways. In this report, we conducted in vitro and in vivo immune function analysis of tumor-draining lymph node (TDLN) cells after anti-CD3/anti-CD28 activation versus anti-CD3 activation alone in a murine tumor model. In cytokine release assays, the doubly activated TDLN cells secreted significantly greater amounts of IFN-gamma and GM-CSF in response to specific tumor antigen compared with anti-CD3 activated cells. In adoptive immunotherapy, the doubly activated TDLN cells were more effective in mediating regression of 3-day pulmonary metastases compared with anti-CD3 activated cells. Although there was predominant proliferation of CD8+ cells after either activation procedure, the mean-fold expansion of CD4+ cells was significantly greater after anti-CD3/anti-CD28 activation than anti-CD3 activation alone. Using magnetic bead-enriched T-cell subsets, we found that either CD4+ or CD8+ doubly activated TDLN cells could independently mediate tumor regression. Furthermore, the doubly activated CD4+ cells were more effective than CD8+ cells in adoptive immunotherapy on a per-cell basis. The antitumor activity mediated by CD4+ or CD8+ cells could be significantly enhanced with the exogenous administration of IL-2. CD28 co-stimulation of tumor-primed lymphoid cells promotes the generation of potent tumor reactive effector cells, particularly CD4+ T cells, with antitumor activity in adoptive immunotherapy.     

CD69-mediated pathway of lymphocyte activation: anti-CD69 monoclonal antibodies trigger the cytolytic activity of different lymphoid effector cells with the exception of cytolytic T lymphocytes expressing T cell receptor alpha/beta

The effect of anti-CD69 monoclonal antibodies (mAbs) on the induction of the cytolytic activity in different types of lymphoid effector cells has been investigated. Three anti-CD69 mAbs, including the reference mAb MLR3 and two new mAbs (c227 and 31C4), have been used. All cloned CD3-CD16+ natural killer (NK) cells belonging to different subsets (as defined by the surface expression of GL183 and/or EB6 antigens) were efficiently triggered by anti-CD69 mAbs and lysed P815 mastocytoma cells in a redirected killing assay. Triggering of the cytolytic activity could also be induced in CD3-CD16- NK clones, which fail to respond to other stimuli (including anti-CD16, anti-CD2 mAbs, or phytohemagglutinin). A similar triggering effect was detected in T cell receptor (TCR) gamma/delta+ clones belonging to different subsets. On the other hand, anti-CD69 mAbs could not induce triggering of the cytolytic activity in TCR alpha/beta+ cytolytic clones. Since all thymocytes are known to express CD69 antigen after cell activation, we analyzed a series of phenotypically different cytolytic thymocyte populations and clones for their responsiveness to anti-CD69 mAb in a redirected killing assay. Again, anti-CD69 mAb triggered TCR gamma/delta+ but not TCR alpha/beta+ thymocytes. Anti-CD69 mAb efficiently triggered the cytolytic activity of "early" thymocytes lines or clones (CD3-4-8-7+), which lack all other known pathways of cell activation. Thus, it appears that CD69 molecules may initiate a pathway of activation of cytolytic functions common to a number of activated effector lymphocytes with the remarkable exception of TCR alpha/beta+ cytolytic cells.     

Anti-CD70 antibodies: a potential treatment for EBV+ CD70-expressing lymphomas

A monoclonal antibody (Rituximab) directed against the B-cell surface antigen, CD20, is increasingly used as a therapy for B-cell lymphomas. However, CD20 is expressed on all normal mature B cells and hence is not a specific tumor target. In contrast, CD70 is expressed on highly activated lymphocytes as well as on many B-cell and T-cell lymphomas but is not expressed on the great majority of B cells and T cells. In this report, we have explored the potential utility of anti-CD70 monoclonal antibodies for treatment of CD70+ EBV+ B-cell lymphomas. Using two Burkitt's lymphoma lines (Raji and Jijoye) that express surface CD70 and a CD70- Burkitt's lymphoma line (Akata), we show that two different monoclonal antibodies directed against human CD70 allow rabbit and human complement to kill EBV+ B cells in a CD70-dependent manner in vitro. In the absence of complement, neither anti-CD70 antibody induced in vitro killing of CD70+ cell lines. Importantly, i.p. injection of anti-CD70 antibodies also inhibited the growth of CD70+ Burkitt's lymphoma cells in severe combined immunodeficient mice but did not inhibit the growth of CD70- Burkitt's lymphoma cells. These results suggest that anti-CD70 antibodies may be useful for the treatment of CD70+ B-cell lymphomas.     

Infusing CD19-directed T cells to augment disease control in patients undergoing autologous hematopoietic stem-cell transplantation for advanced B-lymphoid malignancies

Limited curative treatment options exist for patients with advanced B-lymphoid malignancies, and new therapeutic approaches are needed to augment the efficacy of hematopoietic stem-cell transplantation (HSCT). Cellular therapies, such as adoptive transfer of T cells that are being evaluated to target malignant disease, use mechanisms independent of chemo- and radiotherapy with nonoverlapping toxicities. Gene therapy is employed to generate tumor-specific T cells, as specificity can be redirected through enforced expression of a chimeric antigen receptor (CAR) to achieve antigen recognition based on the specificity of a monoclonal antibody. By combining cell and gene therapies, we have opened a new Phase I protocol at the MD Anderson Cancer Center (Houston, TX) to examine the safety and feasibility of administering autologous genetically modified T cells expressing a CD19-specific CAR (capable of signaling through chimeric CD28 and CD3-ζ) into patients with high-risk B-lymphoid malignancies undergoing autologous HSCT. The T cells are genetically modified by nonviral gene transfer of the Sleeping Beauty system and CAR(+) T cells selectively propagated in a CAR-dependent manner on designer artificial antigen-presenting cells. The results of this study will lay the foundation for future protocols including CAR(+) T-cell infusions derived from allogeneic sources.     

In vitro comparison of three different chimeric receptor-modified effector T-cell populations for leukemia cell therapy

The identification of the optimal T-cell effector subtype is a crucial issue for adoptive cell therapy with chimeric receptor-modified T cells. The ideal T cell population must be able to home toward tumor site, exert prolonged antitumoral activity, and display minimal toxicity against normal tissues. Therefore, we characterized the in vitro antitumoral properties of three effector T-cell populations: Epstein-Barr virus-specific cytotoxic T lymphocytes (EBV-CTLs), cytokine-induced killer (CIK) cells, and γ?δ? T (GDT) cells, after transduction with a chimeric receptor specific for the CD33 antigen, broadly expressed on acute myeloid leukemia cells. EBV-CTLs, CIK, and GDT cells were generated and transduced with high efficiency with a retroviral vector coding for an anti-CD33-ζ chimeric receptor without alterations of their native phenotype. Anti-CD33-ζ chimeric receptor-redirected T cells displayed analogous in vitro chemotactic activity toward CXCL12. In addition, anti-CD33-ζ chimeric receptor-expressing EBV-CTLs, CIK, and GDT cells showed potent and similar cytotoxicity against several CD33? leukemic targets both in short-term 4-hours-?1chromium-release assays (mean killing vs primary leukemic cells at effector:target ratio of 5:1; 50%, 61%, and 50% for EBV-CTLs, CIK, and GDT cells, respectively) and in long-term assays, where they were cocultured with leukemic cells for 6 days on stromal mesenchymal cells (mean survival of primary leukemic cells at effector:target ratio of 1:100; 18%, 16%, and 29% for EBV-CTLs, CIK, and GDT cells, respectively). Moreover, all effector cells acquired consistent capability to proliferate in vitro after contact with CD33? cells and to release high and comparable levels of immunostimulatory cytokines, while secreting similar low amount of immunoregulatory cytokines as the unmanipulated counterpart. Our results indicate that expression of an anti-CD33-ζ chimeric receptor potently and similarly increase the antileukemic functions of different effector T-cell subtypes, underlying the impossibility to identify a more potent T-cell population through in vitro analysis, and consistently with recent observations that have emerged from clinical trials with chimeric receptor-modified T cells, suggesting the need to perform such type of studies in the human setting.     

Phenotypic and functional characterization of human cytolytic T cells lacking expression of CD5.

Although the CD5 (T1) antigen was initially described as a pan-T cell membrane glycoprotein, we report that 14 of 40 normal individuals were found to have 5% or greater of their blood mononuclear cells characterized as CD3 (T3)+ but CD5- by dual immunofluorescence flow cytometry. These cells expressed normal quantities of surface CD3 and CD2 but low levels of CD7, were CD8+ and CD4-, and CD16-. In order to determine whether cells of this phenotype were functional, six CD5- cytolytic T lymphocyte (CTL) clones isolated from normal individuals were studied. The CD5- CTL clones all demonstrated normal cytolytic activity against appropriate target cells. Monoclonal antibodies (MAbs) directed against CD3, CD8, CD2, and lymphocyte function-associated antigen 3, but not against CD5, inhibited cytolytic activity. Changes in intracellular calcium [( Ca2+]i) in response to anti-CD5 and anti-CD3 MAbs were measured. Stimulation by anti-CD5 MAb alone did not give rise to a change in [Ca2+]i. However, under conditions of limiting concentrations of anti-CD3 MAb, preincubation of normal CD5+, but not CD5-, clones with anti-CD5 MAb led to a dramatic enhancement in the ability of anti-CD3 MAb to elicit a rise in [Ca2+]i. We conclude that CD5- T lymphocytes represent a normal lymphoid phenotype. Although CD5 may be involved in T cell activation when present, these CD5- CTL clones appear to express normal cytolytic activity.     

霍奇金淋巴瘤的免疫表型与鉴别诊断

目的　研究霍奇金淋巴瘤 (HL)的免疫表型和鉴别诊断。方法　采用SP免疫组化法检测 5 6例HL患者瘤细胞及背景细胞的免疫表型 ,根据WHO 2 0 0 0淋巴瘤新分类重新评价。结果　HL患者 47例 ,其中结节性淋巴细胞为主型HL(NLPHL) 2例 ,经典型HL(CHL) 4 3例 ,未分类 2例 ;富于T细胞的B细胞淋巴瘤 (TCRBCL) 6例 ,间变性大细胞淋巴瘤 (ALCL) 2例以及转移性肿瘤 1例。NLPHL中L&H细胞呈CD2 0 (+) ,CD1 5(- ) ,CD3 0 (- ) ;背景细胞中TIA 1阳性细胞稀少 ,CD57阳性细胞多见。CHL中诊断性R S细胞及变异型R S细胞呈CD1 5(+) (81% ) ,CD3 0 (+) (10 0 % ) ,其中 3例共同表达CD2 0 呈弱阳性 ;背景细胞中TIA 1阳性细胞多见 ,而CD57阳性细胞稀少。TCRBCL中瘤细胞呈CD2 0(+) ,CD1 5(- ) ,CD3 0 (- ) ;背景细胞中TIA 1阳性细胞增多 ,CD57阳性细胞少见。ALCL中瘤细胞呈CD3(+) ,CD3 0 (+) ,ALK 1(+) ,CD1 5(- ) ,CD2 0 (- ) ,背景细胞中TIA 1阳性细胞多见 ,CD57阳性细胞少见。结论　石蜡免疫组化检测瘤细胞CD2 0 、CD3 、CD1 5、CD3 0 以及背景细胞TIA 1、CD57、CD2 0 和CD45RO 的表达 ,有助于HL的诊断和鉴别诊断     

CD28 interaction with B7 costimulates primary allogeneic proliferative responses and cytotoxicity mediated by small, resting T lymphocytes

Engagement of the CD3/T cell antigen receptor complex on small, resting T cells is insufficient to trigger cell-mediated cytotoxicity or to induce a proliferative response. In the present study, we have used genetic transfection to demonstrate that interaction of the B7-BB1 B cell activation antigen with the CD28 T cell differentiation antigen costimulates cell-mediated cytotoxicity and proliferation initiated by either anti-CD2 or anti-CD3 monoclonal antibody (mAb). Moreover, a B7-negative Burkitt's lymphoma cell line that fails to stimulate an allogeneic mixed lymphocyte response is rendered a potent stimulator after transfection with B7. The mixed leukocyte reaction proliferative response against the B7 transfectant is inhibited by either anti-CD28 or B7 mAb. We also demonstrate that freshly isolated small, resting human T cells can mediate anti-CD3 or anti-CD2 mAb-redirected cytotoxicity against a murine Fc receptor-bearing mastocytoma transfected with human B7. These preexisting cytotoxic T lymphocytes in peripheral blood are present in both the CD4 and CD8 subsets, but are preferentially within the CD45RO+ "memory" population. While small, resting T cells apparently require costimulation by CD28/B7 interactions, this requirement is lost after T cell activation. Anti-CD3 initiates a cytotoxic response mediated by in vitro cultured T cell clones in the absence of B7 ligand. The existence of functional cytolytic T cells in the small, resting T cell population may be advantageous in facilitating rapid responses to immune challenge.     

人鼠嵌合型CD20单克隆抗体增强树突状细胞诱导抗淋巴瘤CTL免疫效应研究

本研究利用人鼠嵌合型抗CD20单克隆抗体对B细胞淋巴瘤的靶向作用特点和其人源Fc段结合人树突状细胞（DC）的特点，探讨抗CD20单克隆抗体激发人DC呈递肿瘤抗原从而诱导抗淋巴瘤的细胞免疫效应。用人体外周血单个核细胞（MNC）体外诱导Dc生成。对高表达CD20的人淋巴瘤细胞株（Raji）分别进行抗CD20单克隆抗体单独作用（R组）、加热诱导凋亡（A组）、诱导凋亡同时加用抗CD20单克隆抗体作用（R＋A组）。经上述处理的肿瘤抗原分别负载于DC，应用透射电子显微镜观察DC对肿瘤抗原的吞噬作用，用抗原处理的DC进行自体混合淋巴细胞反应，应用ELISPOT分析效应细胞一干扰素产生和用MTT法分析效应细胞对Raji靶细胞的杀伤作用。结果表明：R组处理的DC无明显吞噬现象，A组中易见DC吞噬凋亡小体，而R＋A组中DC吞噬较多的细胞碎片。流式细胞术检测显示，3个实验组DC上的CD80、CD86、HLA．DR表达高于对照组，差别显著（P〈0．05），其中R＋A组的CD86表达阳性率明显大于R组和A组（P〈0．05）。淋巴细胞表面抗原检测结果显示，所有实验组CD8^＋细胞的比例均明显高于对照组（P〈0．05），且应用抗CD20单克隆抗体的实验组（R组和R＋A组）CD56^＋细胞数均有所增加，与不用抗CD20单克隆抗体组比较差别显著（P〈0．05）。ELISPOT方法证明，各实验组产生γ-干扰素的细胞数均高于对照组，且当效靶比为1：10时，R＋A组斑点数明显高于其它组（P〈0．05）。MTT法测定杀伤实验结果表明，各实验组对Raji细胞的杀伤率均较对照组增加，其中R＋A组的杀伤率高于R组和A组，具有显著统计学差异（P〈0．05）。结论：抗CD20单克隆抗体能够介导DC产生抗淋巴瘤效应，即激活并扩增肿瘤特异性细胞毒性淋巴细胞（CTL）和自然杀伤细胞（NK），抗CD20单克隆抗体同时加凋亡诱导处理肿瘤细胞作为抗原冲击树突状细胞，能进一步增强抗淋巴瘤的细胞免疫效应。     

Targeting of natural killer-like T immunologic effector cells against leukemia and lymphoma cells by reverse antibody-dependent cellular cytotoxicity

Recently, highly efficient natural killer-like T immunologic effector cells called cytokine-induced killer (CIK) cells have been described. Most interestingly, CIK cells have been shown to eradicate established human lymphoma cells in a severe combined immunodeficient (SCID) mouse xenograft model in vivo. The current study was aimed at increasing the sensitivity of leukemia and lymphoma cells to CIK cells. In particular, the authors wanted to target CIK cells to leukemia and lymphoma cells via reverse antibody-dependent cellular cytotoxicity. Binding of an anti-CD3 monoclonal antibody to CIK cell cultures derived from patients with lymphoma was shown using flow cytometric analysis. For the target side, several B-cell lines were found to express CD19 on the cell surface. There was an impressive increase in sensitivity to CIK-mediated lysis of various lymphoma and leukemia cell lines by preincubation of the targets with a monoclonal antibody against CD3. This increase could be partially blocked by preincubation with anti-CD16 (Fc receptor III) and anti-CD32 (Fc receptor II) antibodies. These data suggest that the increase in cytotoxic activity is caused by Fc receptor-mediated antibody binding. Cytotoxic activity could be further increased by adding an anti-CD28 antibody in addition to anti-CD3. Finally, there was a further increase in sensitivity to CIK-mediated lysis of CD19+ malignant cells using the bispecific OKT3xHD37 antibody with specificity against CD3 and CD19. Interestingly, preincubation of malignant cells with an anti-CD3 monoclonal antibody followed by addition of the bispecific OKT3xHD37 antibody led to a further increase of cytotoxic sensitivity compared with the addition of the bispecific antibody alone. In conclusion, these data suggest that cytotoxic activity of immunologic effector cells can be increased not only by using the bispecific antibody OKT3xHD37 in vitro but also by preincubation of CD19+ leukemia and lymphoma cells with a monoclonal antibody against CD3. In addition, the immunostimulatory effect of the bispecific antibody OKT3xHD37 can be further increased by adding a monoclonal antibody against CD3.