Costimulation by CD48 and B7-1 induces immunity against poorly immunogenic tumors

Genetic modification of many types of mouse tumors to express the B7-1 or B7-2 molecules, natural ligands for the T cell-costimulatory molecule CD28, increases their immunogenicity. However, even after transfection with the B7-1 and/or B7-2 genes, poorly immunogenic tumors fail to elicit and efficient immune response. We report here that two such tumors, the Ag104A sarcoma and the K1735-M2 melanoma, become immunogenic after transfection of the genes encoding murine B7-1 together with CD48, which is the natural ligand for CD2. Tumor-specific CD8+ cytotoxic T lymphocytes were readily generated and were effective for adoptive immunotherapy of metastasis induced by wild-type Ag104A sarcoma cells. A similar approach may be useful for developing therapy for other poorly immunogenic tumors, including those in humans.     

Complete regression of large solid tumors using engineered drug-resistant hematopoietic cells and anti-CD137 immunotherapy

Combining chemotherapy and immunotherapy is problematic because chemotherapy can ablate the immune responses initiated by modulators of the immune system. We hypothesized that protection of immunocompetent cells from the toxic effects of chemotherapy, using drug resistance gene therapy strategies, would allow the combined use of chemotherapy and immunotherapy. In wild-type mice, the antitumor effectiveness of an immunotherapy regimen employing an agonistic anti-CD137 antibody is diminished with escalating doses of the antifolate trimetrexate (TMTX). Using retroviral gene transfer of a mutant form of dihydrofolate reductase (L22Y-DHFR), hematopoietic stem cells were genetically engineered to withstand the toxic effects of TMTX. Mice transplanted with L22Y-DHFR-modified bone marrow were then challenged with AG104 sarcoma cells and treated with TMTX only, anti-CD137 only, or a combination of chemotherapy and immunotherapy. Although tumor burden was transiently decreased during TMTX administration, no mice treated with TMTX alone survived the tumor challenge, whereas approximately 40% of transplanted mice treated with anti-CD137 alone survived. However, 100% of mice survived with complete tumor regression after transplantation with L22Y-DHFR-transduced bone marrow followed by combined treatment with TMTX and anti-CD137. In addition, adoptive transfer of splenocytes from cured mice extended the survival of tumor- bearing animals by approximately 3 weeks compared with controls. Therefore, protection of the hematopoietic system can allow for the combined administration of chemotherapy and immunotherapy, which results in complete tumor clearance.     

Interferon-alpha gene therapy in combination with CD80 transduction reduces tumorigenicity and growth of established tumor in poorly immunogenic tumor models

Interferon-alpha (IFN-alpha) or CD80 transduction of tumor cells individually reduces tumorigenicity and enhances antitumor responses. Here, we report that the combination of IFN-alpha and CD80 cancer gene therapy in poorly immunogenic murine tumor models, the colorectal adenocarcinoma cell line MC38, and the methylcholanthrene-induced fibrosarcoma cell line MCA205 reduces tumor growth more efficiently without affecting in vitro growth. Wild-type (WT), neomycin-resistance (Neo) gene-, or CD80-transduced tumor cells grew progressively in all immunocompetent mice. In contrast, IFN-alpha-transduced MC38 or MCA205 cells were rejected in 13 of 15 and seven of 15 mice, respectively. Synergistic effects were observed when IFN-alpha- and CD80-transduced tumor cells were mixed and inoculated. These admixed cells were rejected by 14 of 15 (MC38) or seven of 15 mice (MCA205), whereas, a mixture of IFN-alpha and Neo cells or CD80 and Neo cells led to tumors associated with progressive growth. Induction of long-lasting tumor immunity against WT tumor cells was demonstrated by rejection of a subsequent rechallenge in 10 of 13 (MC38) and six of seven (MCA205) tumor-free mice. The therapeutic efficacy with established WT MC38 tumors was shown when mice were treated with a vaccine consisting of repetitive injections of IFN-alpha- and CD80-transduced MC38 cells into the contralateral flank (P < 0.01). This treatment was associated with accumulation of CD4+, CD8+ cells and dendritic cells within the established tumor, demonstrating induction of antitumor immune responses. Combination gene therapy using IFN-alpha and CD80 is an effective immune therapy of cancer and could be considered for clinical trials.     

CD23 antigen regulation and signaling in chronic lymphocytic leukemia.

B lymphocytes from patients with chronic lymphocytic leukemia (B-CLLs), strongly express the CD23 antigen, a surface marker with significant prognostic importance in this disease. Because we previously reported that IL-4 shows a poor capacity for CD23 expression on B-CLLs, we first examined the possible mechanisms underlying CD23 overexpression on B-CLLs and found that mitogen-activated CLL T cells release soluble factors that are capable, in synergy with IL-4, of strongly inducing CD23. Using neutralizing Abs, we noticed that the T-cell-derived enhancing activity is entirely ascribed to the combined effects of IFN gamma (potent inhibitor of CD23 on normal B cells), TNF alpha (which has no effect on normal B cells), and IL-2 (which has a slight enhancing effect on both CLL and normal B cells). Furthermore, recombinant IFN gamma as well as IFN alpha, TNF alpha, and IL-2 (but not IL-3, IL-5, IL-6, IL-7, and lymphotoxin) significantly enhance CD23 protein and mRNA expression on B-CLLs, in the presence or absence of IL-4. Inasmuch as optimal CD23 expression absolutely requires the combination of IFN gamma, IL-2, TNF alpha (the production of which is increased in CLL disease), and IL-4, it was relevant to show that IL-4 mRNA is indeed expressed in fresh T-CLL cells. We next examined the possible role of CD23 in the regulation of B-CLL proliferation. Signaling through CD23 via ligation of the antigen by F(ab')2 anti-CD23 MAb but not Fab fragments inhibits the cytokine-induced B-CLL DNA synthesis. It is concluded that the CD23 gene is abnormally regulated in B-CLL disease and that cross-linking of CD23 molecule delivers a negative growth signal to the leukemic B cells.     

Interleukin 1-induced, T cell-mediated regression of immunogenic murine tumors. Requirement for an adequate level of already acquired host concomitant immunity

Intraperitoneal injection of human rIL-1 in a dose of 0.5 microgram daily for 5 d, or 1 microgram daily for 3 d, was capable of causing complete regression of immunogenic SA1 sarcoma growing subcutaneously in syngeneic or semisyngeneic mice. Higher doses of IL-1 were not more therapeutic against the SA1 sarcoma, but needed to be given to cause complete regression of the immunogenic L5178Y lymphoma. On the other hand, the P815 mastocytoma was much less responsive to IL-1 therapy, in that it failed to undergo complete regression in response to doses of IL-1 capable of causing regression of the L5178Y lymphoma. IL-1 caused regression of the SA1 sarcoma when given on days 6-8 of tumor growth, but not when given on days 1-3. This refractoriness of a small tumor to IL-1 therapy suggests that the antitumor action of IL-1 is based on an underlying host-immune response that is not generated until after day 3 of tumor growth. Direct evidence for the participation of host immunity in IL-1-induced tumor regression was supplied by results showing that IL-1 was not therapeutic against the SA1 sarcoma growing in T cell-deficient (TXB) mice, unless these mice were first infused with Ly-2+ and L3T4+ T cells from donor mice bearing an established SA1 sarcoma. In contrast, normal T cells, or T cells from donor mice bearing a YAC-1 lymphoma, failed to provide TXB recipients with the ability to cause regression of their SA-1 sarcoma in response to IL-1 treatment. The results are in keeping with the interpretation that exogenous IL-1, by augmenting the production of tumor-sensitized T cells, converts a subtherapeutic level of host immunity to a therapeutic level. The results suggest, in addition, that IL-1 only stimulates the replication of T cells that are already engaged in the antitumor immune response.     

CD137 enhances cytotoxicity of CD3CD56 cells and their capacities to induce CD4 Th1 responses

CD137 (4-1BB) is a TNFR superfamily member that mediates the costimulatory signal resulting in T cells and NK cells proliferation and cytokines production, but the effects of CD137 signaling on CD3⁺CD56⁺ cell subpopulation have not been well-documented. The aim of this study was to investigate the effects of CD137 signaling on regulation of CD3⁺CD56⁺ cell function. Anti-CD137 mAb or mouse IgG1 isotype control was added to CIK cell culture to determine the effects of proliferation and anti-tumor effects on CD3⁺CD56⁺ cells. We observed that anti-CD137 mAb could dramatically promote proliferation of CIK cells. And CD137–CIK cells and CD3⁺CD56⁺ cell subpopulation within them possessed higher ability to kill tumor cell line A549. The SCID mice engrafted with A549 cells and treated with CD137–CIK cells have prolonged survival. Further studies revealed that the percentages of CD3⁺CD56⁺ cells were elevated significantly in CD137–CIK cells. The expression of NKG2D was up-regulated on CD3⁺CD56⁺ cells from CD137–CIK cells. The expression of IFN-γ, IL-2 and TNF-α increased significantly whereas the production of TGF-β₁, IL-4 and IL-10 decreased in CD3⁺CD56⁺ cells from CD137–CIK cells. In addition, anti-CD137 mAb can elevate the capacity of CD3⁺CD56⁺ cells to induce CD4⁺ Th1 responses. We further showed that the anti-CD137 mAb also had the same effects on CD3⁺CD56⁺ cells expanded from the PBMCs of patients with NSCLC. We concluded that CD137 signaling could enhance the abilities of CIK cells to kill tumor cells in vitro and in vivo via increasing the proportion of CD3⁺CD56⁺ cells and their cytotoxicity. Furthermore, CD137 signaling can elevate the capacity of CD3⁺CD56⁺ cells to induce CD4⁺ Th1 responses which may enhance their anti-tumor activity indirectly. Taken together, our studies could be considered as valuable in CIK cells-based cancer immunotherapy.     

Regulation of cytokine signaling by B cell antigen receptor and CD40-controlled expression of heparan sulfate proteoglycans

Recently, biochemical, cell biological, and genetic studies have converged to reveal that integral membrane heparan sulfate proteoglycans (HSPGs) are critical regulators of growth and differentiation of epithelial and connective tissues. As a large number of cytokines involved in lymphoid tissue homeostasis or inflammation contain potential HS-binding domains, HSPGs presumably also play important roles in the regulation of the immune response. In this report, we explored the expression, regulation, and function of HSPGs on B lymphocytes. We demonstrate that activation of the B cell antigen receptor (BCR) and/or CD40 induces a strong transient expression of HSPGs on human tonsillar B cells. By means of these HSPGs, the activated B cells can bind hepatocyte growth factor (HGF), a cytokine that regulates integrin-mediated B cell adhesion and migration. This interaction with HGF is highly selective since the HSPGs did not bind the chemokine stromal cell-derived factor (SDF)-1 alpha, even though the affinities of HGF and SDF-1alpha for heparin are similar. On the activated B cells, we observed induction of a specific HSPG isoform of CD44 (CD44-HS), but not of other HSPGs such as syndecans or glypican-1. Interestingly, the expression of CD44-HS on B cells strongly promotes HGF-induced signaling, resulting in an HS-dependent enhanced phosphorylation of Met, the receptor tyrosine kinase for HGF, as well as downstream signaling molecules including Grb2-associated binder 1 (Gab1) and Akt/protein kinase B (PKB). Our results demonstrate that the BCR and CD40 control the expression of HSPGs, specifically CD44-HS. These HSPGs act as functional coreceptors that selectively promote cytokine signaling in B cells, suggesting a dynamic role for HSPGs in antigen-specific B cell differentiation.     

Targeting antigens to CD180 rapidly induces antigen-specific IgG,affinity maturation,and immunological memory

Antigen (Ag) targeting is an efficient way to induce immune responses. Ag is usually coupled to an antibody (Ab) specific for a receptor expressed on dendritic cells (DCs), and then the Ag–anti-receptor is inoculated with an adjuvant. Here we report that targeting Ag to a receptor expressed on both B cells and DCs, the TLR orphan receptor CD180, in the absence of adjuvant rapidly induced IgG responses that were stronger than those induced by Ag in alum. Ag conjugated to anti-CD180 (Ag-αCD180) induced affinity maturation and Ab responses that were partially T cell independent, as Ag-specific IgGs were generated in CD40- and T cell–deficient mice. After preimmunization with Ag-αCD180 and boosting with soluble Ag, both WT and CD40 knockout (KO) mice rapidly produced Ag-specific IgG-forming cells, demonstrating that Ag–anti-CD180 induces immunological memory. The potent adjuvant effect of Ag-αCD180 required Ag to be coupled to anti-CD180 and the responsive B cells to express both CD180 and an Ag-specific B cell receptor. Surprisingly, CD180 Ag targeting also induced IgG Abs in BAFF-R KO mice lacking mature B cells and in mice deficient in interferon signaling. Targeting Ag to CD180 may be useful for therapeutic vaccination and for vaccinating the immune compromised.Antigen (Ag) targeting is a method to efficiently induce immune responses by delivering Ags directly to APCs such as DCs by coupling them to antibodies (Abs) specific for APC-restricted surface molecules (Caminschi et al., 2009; Caminschi and Shortman, 2012). Many Ag-targeting approaches have directed Ags to DC subsets via mAbs specific for C-type lectin receptors (Sancho and Reis e Sousa, 2012). This method of immunization reduces the amount of Ag required and directs the immune response toward certain effector cell functions. Depending on the cell surface receptor targeted by an mAb, a different kind of immune response may be induced. For example, delivery of Ag to Dectin-1 induces strong CD4⁺ T cell responses if administered with adjuvant (Carter et al., 2006); targeting to DEC205 induces strong CD8⁺ T cell responses with adjuvant (Dudziak et al., 2007); targeting to DCIR2 in the absence of adjuvants generates strong CD4⁺ T cell help and extrafollicular (EF) IgG1 Ab responses (Chappell et al., 2012); and targeting to Clec9A generates CD8⁺ T cell responses with adjuvant and efficiently activates Tfh follicular helper cells for Ab production without adjuvant (Lahoud et al., 2011).In this study, we investigated the effect of targeting Ags to a receptor expressed on both DCs and B cells. We selected the 95-kD B cell–associated surface molecule CD180 (also called Bgp95 or RP105) as a target because (a) ligating CD180 with mAb triggers B cell activation and proliferation (Valentine et al., 1988; Miyake et al., 1994) and (b) CD180 is an orphan member of the TLR family most closely related to TLR4 (Miyake et al., 1995), an effective target for adjuvants (Alving et al., 2012). Although CD180, unlike TRL4 and other TLRs, lacks a cytoplasmic TIR domain, it initiates a BCR-like signaling cascade that does not use TLR signaling adaptors (Valentine et al., 1988; Miyake et al., 1994; Chan et al., 1998; Yazawa et al., 2003; Hebeis et al., 2004, 2005); (c) CD180 internalizes after ligation, suggesting that Ag-αCD180 might be processed by DCs and/or B cells and activate CD4 T cell helper cells; and (d) we previously found that inoculation of mice with a high dose of anti-CD180 induces extremely rapid and robust polyclonal IgG production, even in the absence of CD40 signaling or T cells (Chaplin et al., 2011).We evaluated whether Ag delivery to CD180 was able to induce Ag-specific IgG responses and found that mice inoculated i.v. with Ag-αCD180 rapidly produced Ag-specific IgG responses that were greater than mice immunized with Ag in alum. Remarkably, targeting Ags via CD180 in a single inoculation without adjuvant primed mice to mount secondary immune responses, even in CD40-deficient mice. The powerful adjuvant effect of Ag-αCD180 required B cells to express both an Ag-specific BCR and CD180. Thus, coupling Ags to anti-CD180 is an effective means for rapidly raising Ag-specific IgG responses that may find efficacy for both therapeutic and prophylactic vaccines.     

γ-干扰素、白细胞介素4与CD25在角膜移植免疫排斥反应中的作用

目的:角膜移植免疫排斥反应是一个多因素参与的调节过程,近年来研究表明细胞因子在角膜移植免疫中起重要作用.实验拟验证γ-干扰素、白细胞介素4及CD25在大鼠角膜移植免疫排斥反应中的作用.方法:①实验于2006-10/2007-05在南方医科大学南方医院实验动物中心完成.选用Wistar大鼠24只,SD大鼠54只,实验方法符合动物伦理学要求.②将54只SD大鼠按随机数字表法分为3组,正常组6只,角膜移植组及地塞米松组均24只.后两组制备Wistar→SD角膜移植大鼠模型,受体选择右眼手术,供体提供双眼角膜.③用裂隙灯观察移植排斥情况;利用反转录-聚合酶链反应检测植片内γ-干扰素、CD25 mRNA的表达;应用酶联免疫吸附实验检测房水和血清中γ-干扰素、白细胞介素4含量;应用流式细胞术检测移植前后不同时相外周血淋巴细胞CD25的表达;术后第11天,应用免疫组织化学方法检测角膜CD4 ,CD8 和CD25 T细胞的表达.结果:54只SD大鼠全部进入结果分析.①地塞米松组大鼠发生角膜移植排斥反应的时间长于角膜移植组(P=0.000).②正常角膜植片无CD25、γ-干扰素mRNA表达,角膜移植组术后第11天角膜植片内γ-干扰素、CD25 mRNA的表达较地塞米松组增强(P < 0.05).③角膜移植组角膜移植术后6,11 d血清γ-干扰素含量高于正常组(P < 0.05);术后11 d含量高于术后6,24 d(P < 0.01);地塞米松组术后6,11 d低于同期角膜移植组(P < 0.05).④角膜移植组角膜移植术后6,11,24 d房水γ-干扰素、白细胞介素4含量均高于正常组(P < 0.05);地塞米松组术后6,11 d均低于同期角膜移植组(P < 0.05～0.01).⑤地塞米松组术后6,11 d外周血CD3 CD25 T/CD3 T比值低于同期角膜移植组(P < 0.05).⑥术后第11天角膜移植组植片内CD4,CD8及CD25明显表达,地塞米松组CD4,CD8及CD25表达明显减弱.结论:CD25、γ-干扰素和白细胞介素4在角膜移植免疫排斥反应过程中发挥重要的作用;促进白细胞介素4表达,抑制γ-干扰素及CD25产生,对降低角膜移植免疫排斥反应具有积极的作用.术后动态检测外周血CD25和γ-干扰素的表达有助于临床了解局部免疫反应程度并预测角膜移植排斥反应的发生.     

Optimizing adoptive polyclonal T cell immunotherapy of lymphomas, using a chimeric T cell receptor possessing CD28 and CD137 costimulatory domains

We previously demonstrated the feasibility of generating therapeutic numbers of cytotoxic T lymphocyte (CTL) clones expressing a CD20-specific scFvFc:CD3zeta chimeric T cell receptor (cTCR), making them specifically cytotoxic for CD20+ B lymphoma cells. However, the process of generating and expanding he CTL clones was laborious, the CTL clones expressed the cTCR at low surface density, and they exhibited suboptimal proliferation and cytotoxicity. To improve the performance of the CTLs in vitro and in vivo, we engineered "second-generation' plasmid constructs containing a translational enhancer (SP163) and CD28 and CD137 costimulatory domains in cis with the CD3zeta intracellular signaling domain of the cTCR gene. Furthermore, we verified the superiority of generating genetically modified polyclonal T cells expressing the second-generation cTCR rather than T cell clones. Our results demonstrate that SP163 enhances the surface expression of the cTCR; that the second-generation cTCR improves CTL activation, proliferation, and cytotoxicity; and that polyclonal T cells proliferate rapidly in vitro and mediate potent CD20-specific cytotoxicity. This study provides the preclinical basis for a clinical trial of adoptive T cell immunotherapy for patients with relapsed CD20+ mantle cell lymphoma and indolent lymphomas.     

The CD34 antigen: structure, biology, and potential clinical applications.

The diversity of function of mature circulating blood cells is reflected in their respective complements of cell-surface molecules and receptors. Although monoclonal antibodies have been instrumental in the identification and characterization of many cell-surface molecules on mature hematopoietic cells, the CD34 antigen represents to date, the only molecule, similarly identified, whose expression within the blood system is restricted to a small number of primitive progenitor cells in the bone marrow. Although its precise function remains unknown, the pattern of expression of the CD34 structure suggests that it plays an important role in early hematopoiesis. The availability of CD34 antibodies has greatly aided the development of techniques for the enrichment of primitive progenitor cells for studies of hematopoiesis in vitro. Additionally, the use of CD34 antibodies for the 'positive selection' of hematopoietic stem/progenitor cells represents and alternative strategy to 'negative selection' or purging for the large-scale manipulation of bone marrow cells prior to transplantation. The availability of pure populations of the most primitive hematopoietic progenitor cells may also facilitate the development of genetic techniques for the repair of specific blood cell disorders. In this article, we review the biology of the CD34 molecule and assess some of the roles for CD34 antibodies in immunopathology and for progenitor/stem cell purification in clinical applications.     

Enhanced therapeutic potential of adoptive immunotherapy by in vitro CD28/4-1BB costimulation of tumor-reactive T cells against a poorly immunogenic, major histocompatibility complex class I-negative A9P melanoma

Costimulation plays a critical role in T-cell activation and amplification of anti-tumor immunity. Although CD28 engagement triggers an early activation signal, activation-induced 4-1BB molecule on T cells transmits a crucial signal for further expansion and maturation of effector cells. In this report, the authors show that costimulation through CD28 and 4-1BB pathways synergistically enhances the therapeutic efficacy of T cells from tumor-draining lymph nodes. Intravenous adoptive transfer of costimulated T cells into mice bearing disseminated micrometastasis of a poorly immunogenic, major histocompatibility complex class I-negative A9P melanoma results in a 60% cure rate. Autopsy of mice that died after unsuccessful treatment revealed tumor growth in the liver, spleen, and skin with minimal or no evidence of pulmonary disease. In contrast, mice that received no treatment or noncostimulated T cells had massive pulmonary tumors, suggesting that adoptively transferred T cells are less effective against growth of extrapulmonary tumors. These results show that costimulation of tumor-draining lymph node T cells through CD28 and 4-1BB increases their potential for cancer immunotherapy and suggests that improper trafficking of tumor-reactive T cells to extrapulmonary sites must be improved to enhance clinical efficacy.     

CD137在Treg细胞上的表达及对其功能的抑制作用

目的探讨CD137分子在CD4 CD25 调节性T细胞(Treg)上的表达及其生物学意义。方法抗人CD137单抗加入PHA活化的T细胞培养体系中,流式细胞术分析细胞表型的变化,细胞计数分析细胞的增殖。结果流式细胞术分析(FACS)结果显示,PHA活化后CD137在Treg细胞表面上调表达。细胞计数结果表明,抗CD137单抗加入PHA活化的T细胞培养体系中T细胞增殖的总数明显增加,而FACS结果显示,其中Treg细胞的含量明显下降,并下调CD95的表达。结论Treg细胞活化后,CD137表达明显增加,其介导的共刺激信号可发挥抑制Treg细胞功能的作用,进而促进其它T亚群的增殖。     

PG490-88, a derivative of triptolide, causes tumor regression and sensitizes tumors to chemotherapy

Treatment of solid tumors with combinations of chemotherapeutic agents has not led to significant increases in long-term survival. Recent studies support a role for inhibitors of checkpoint arrest as a means to enhance the cytotoxicity of chemotherapy. We have shown previously that triptolide (PG490), an oxygenated diterpene derived from a Chinese medicinal plant, induces apoptosis in cultured tumor cells and sensitizes tumor cells to topoisomerase inhibitors by blocking p53-mediated induction of p21. Here we extend our studies to a tumor xenograft model and evaluate the efficacy and safety of PG490-88 (14-succinyl triptolide sodium salt), a water-soluble prodrug of PG490. We also look at the combination of PG490 or PG490-88 with CPT-11, a topoisomerase I inhibitor, in cultured cells and in the tumor xenograft model. We show that PG490-88 is a safe and potent antitumor agent when used alone, causing tumor regression of lung and colon tumor xenografts. We also show that PG490-88 acts in synergy with CPT-11 to cause tumor regression. A phase I trial of PG490-88 for solid tumors began recently and safety and optimal dosing data should accrue within the next 12 months. Our findings that PG490-88 causes tumor regression and that it acts in synergy with DNA-damaging chemotherapeutic agents suggest a role as an antineoplastic agent and chemosensitizer for the treatment of patients with solid tumors.     

Components of the human T lymphocyte antigen receptor complex, CD3-p28 and CD3-gamma, are biochemically distinct

A recently described subunit of the T cell antigen receptor-CD3 complex, p28, is very similar to the mature CD3-gamma subunit with respect to electrophoretic mobility. We demonstrated, by one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and endo-beta-n-acetylglucosaminidase digestion, that CD3-p28 and CD3-gamma coexist in CD3-specific immunoprecipitates from the human T lymphocyte hybrid cell line 255.88, which was labeled by biosynthetic incorporation of radioactive amino acids. By partial proteolysis and peptide mapping, we demonstrated that CD3-p28 and CD3-gamma are distinct members of the CD3 complex.     

Increased expression of CD54, CD18, MHC class II molecules,and proliferating cell nuclear antigen in acute puromycin aminonucleoside nephrosis

Cellular infiltration to renal tissues is an important feature during acute puromycin aminonucleoside nephrosis (PAN) in rats. The mechanisms responsible for this infiltration are poorly understood. To elucidate the participation of adhesion molecules in PAN, nephrosis was induced in rats by intraperitoneal puromycin aminonucleoside injection. Controls represent animals injected with a 0.9% saline solution. ICAM-1 (intercellular adhesion molecule 1), CD18 (beta chain of lymphocyte-function-associated antigen), LCA (leukocyte common antigen), ED1 (monocyte/macrophage marker), and proliferating cell nuclear antigen expressions were evaluated in renal tissues 1, 2, and 7 weeks after injection. Frozen sections from PAN rat kidneys showed increased expressions of ICAM-1 and its ligand, and these findings were associated with increased levels of LCA+ and ED1+ cells in glomerulus and interstitium. The kinetics of leukocyte infiltration was similar to the kinetics of ICAM-1 expression: high values at week 2 which returned to normal values at week 7. Increased glomerular and interstitial proliferative activities (proliferating cell nulear antigen positive cells) were also found at week 2 of nephrosis. There was a correlation between ICAM-1 expression and numbers of LCA+ and ED1+ cells and between numbers of LCA+ cells and proliferating cells in glomerulus and interstitium. Correlations between glomerular and tubular ICAM-1 expression, interstitial leukocyte infiltration, and glomerular, interstitial, and tubular proliferative activities with the proteinuria were also observed during the nephrotic phase. In addition, increased lymphocyte binding to PAN renal tissues was observed, and this binding was diminished by anti-LFA-1beta monoclonal antibody pretreatment of lymphocytes. A similar result was found with anti-ICAM-1 monoclonal antibody pretreatment of renal tissues. Our results suggest that increased expression of ICAM-1 and proliferative activity could be important determinants in the renal hypercellularity found in this experimental model.     

CD4 and CD8 T-lymphocyte recognition of prostate specific antigen in granulomatous prostatitis

In order to develop immunotherapies for prostate cancer, many groups are exploring vaccination strategies to induce an immune response against prostate specific antigen (PSA). To determine if T-cell recognition of PSA might be a feature of a naturally occurring human disease, we have studied patients with prostatitis, a poorly understood clinical syndrome of men in which there is evidence that an immune response directed against the prostate may be occurring. We wished to determine if a T-cell response to PSA might be occurring in these patients. We generated long-term T-cell lines from peripheral blood mononuclear cells (PBMC) of one patient with granulomatous prostatitis using purified PSA as an antigen. Several CD4+ and CD8+ TcR alpha/beta+ T-cell lines were selected for PSA reactivity as measured by at least a threefold increase in IFN-gamma secretion in response to PSA presented by irradiated autologous PBMC. CD4 and CD8 T-cell lines recognized PSA in the context of HLA-DRbeta1*1501 and HLA-B*0702, respectively. The specificity and HLA restriction of the lines was confirmed using EBV-B cell lines infected with a recombinant PSA-expressing vaccinia virus and also engineered to express PSA by retroviral transfection. HLA-matched targets infected by control vector as well as HLA-mismatched PSA-expressing targets did not induce the response. The data demonstrate that PSA-specific T cells are present in the PBMC of this patient with granulomatous prostatitis, who may be manifesting naturally the type of immune response directed at the prostate that is the goal of prostate cancer immunotherapy. However, the Class I-restricted epitope has not yet been demonstrated to be expressed on the surface of prostate cancer cells. To our knowledge, this is the first demonstration of HLA-DRB1*1501- or HLA-B*0702-restricted responses to PSA and extends the number of HLA molecules accommodating the use of PSA antigen as a candidate vaccine for prostate cancer immunotherapy.     

Initial assessment of tumor-associated antigen CA-125 in patients with ovarian, cervical, and testicular tumors

Serum CA-125, a glycoprotein antigen, has been measured in serum of patients with ovarian cancer, cervical cancer, or nonseminomatous germ-cell tumor of testis. Increased concentrations were found in 21 of 27 patients with epithelial ovarian cancer and two of three patients with ovarian teratoma. Changes in CA-125 concentrations in serum during chemotherapy mirrored the progress of the disease as assessed by clinical and radiological evidence. Although CA-125 provides no real asset for diagnosis, it should have value as a marker for monitoring response to chemotherapy.