A novel approach to measuring cell-mediated lympholysis using quantitative flow and imaging cytometry

In this study, we established a novel isotope-free approach for the detection of cell-mediated lympholysis (CML) in MHC defined peripheral blood mononuclear cells (PBMCs) using multiparameter flow and imaging cytometry. CML is an established in vitro assay to detect the presence of cytotoxic effector T-lymphocytes precursors (CTLp). Current methods employed in the identification of CTLp in the context of transplantation are based upon the quantification of chromium ((51)Cr) released from target cells. In order to adapt the assay to flow cytometry, primary porcine PBMC targets were labeled with eFluor670 and incubated with major histocompatibility complex (MHC) mismatched effector cytotoxic lymphocytes (CTLs). With this method, we were able to detect target-specific lysis that was comparable to that observed with the (51)Cr-based assay. In addition, the use of quantitative cell imaging demonstrates the presence of accessory cells involved in the cytotoxic pathway. This innovative technique improves upon the standard (51)Cr release assay by eliminating the need for radioisotopes and provides enhanced characterization of the interactions between effector and target cells. This technique has wide applicability to numerous experimental and clinical models involved with effector-cell interactions.

Acute renal endothelial injury during marrow recovery in a cohort of combined kidney and bone marrow allografts

An idiopathic capillary leak syndrome ('engraftment syndrome') often occurs in recipients of hematopoietic cells, manifested clinically by transient azotemia and sometimes fever and fluid retention. Here, we report the renal pathology in 10 recipients of combined bone marrow and kidney allografts. Nine developed graft dysfunction on day 10-16 and renal biopsies showed marked acute tubular injury, with interstitial edema, hemorrhage and capillary congestion, with little or no interstitial infiltrate (≤10%) and marked glomerular and peritubular capillary (PTC) endothelial injury and loss by electron microscopy. Two had transient arterial endothelial inflammation; and 2 had C4d deposition. The cells in capillaries were primarily CD68(+) MPO(+) mononuclear cells and CD3(+) CD8(+) T cells, the latter with a high proliferative index (Ki67(+) ). B cells (CD20(+) ) and CD4(+) T cells were not detectable, and NK cells were rare. XY FISH showed that CD45(+) cells in PTCs were of recipient origin. Optimal treatment remains to be defined; two recovered without additional therapy, six were treated with anti-rejection regimens. Except for one patient, who later developed thrombotic microangiopathy and one with acute humoral rejection, all fully recovered within 2-4 weeks. Graft endothelium is the primary target of this process, attributable to as yet obscure mechanisms, arising during leukocyte recovery.

When monocytes and platelets compete: The effect of platelet count on the flow cytometric measurement of monocyte CD36

BACKGROUND

Flow cytometric measurement of monocyte surface CD36 is relevant to several conditions including diabetes, cardiovascular disease, lipid disorders, platelet isoimmunization, and susceptibility to P falciparum malaria. CD36 is also strongly expressed on platelets where it is also known as platelet glycoprotein IV.

METHODS

Whole blood samples, containing identical monocyte concentrations, were adjusted to contain platelets ranging from 20,000/uL to 600,000/uL, were stained with fluorescent-labeled anti-CD36, and analyzed by flow cytometry.

RESULTS

CD36 median fluorescent intensity (MFI) observed on monocytes decreased as the platelet concentration in the sample increased with more than a 50% decline in monocyte MFI over the normal range of platelet values. The effect was not abolished by using larger volumes of monoclonal antibody and was observed with different clones of reagent anti-CD36. The findings were most consistent with competition by platelets for the CD36 reagent. Similar findings were observed with antibody to class I HLA. Under defined assay conditions, monocyte CD36 MFI declined with rising platelet concentration in a predictable fashion following an inverse linear relationship.

CONCLUSIONS

Measurement of CD36 expression on monocytes by flow cytometry in whole blood samples is affected by the sample platelet count. When comparing the monocyte CD36 expression among different individuals, our approach can be used to adjust measured monocyte CD36 expression for the effect of the platelet concentration in the sample. Competition by platelets for monoclonal reagents may occur in other settings when whole blood assays are used and when the target antigen is strongly expressed on both platelets and leukocytes.

Overexpression of human phosphoglycerate kinase 1 (PGK1) induces a multidrug resistance phenotype

BACKGROUND

Multidrug resistance is a significant barrier to the development of successful cancer treatment. To identify genetic alterations that are directly involved in paclitaxel resistance, a functional cloning strategy was developed.

MATERIALS AND METHODS

Using mRNA from paclitaxel resistant human ovarian cancer cell line SW626TR, a cDNA library was established in a pCMV-Script vector that permits expression of cDNA inserts in mammalian cells. Transfection of the pCMV-Script/SW626TR cDNA library into the paclitaxel-sensitive human osteogenic sarcoma cell line, U-20S, resulted in several paclitaxel-resistant clones.

RESULTS

DNA sequencing of clone C16 demonstrates complete homology to human phosphoglycerate kinase 1 (PGK1). Retransfection of the PGK1 insert into U-20S confers a multidrug resistant phenotype, characterized by a 30-fold increase in paclitaxel resistance, and cross-resistance to vincristine; adriamycin and mitoxantrone, but not methotrexate or cisplatin. Enzymatic analysis of the PGK1 transfectants demonstrates an increase in PGK1 activity as compared to the parental cell line, U-20S. Northern and Western analysis of PGK1 transfectants reveals no change in MDR-1 expression compared with the parental cell line. In addition, co-culture of PGK1 transfectants with verapamil only partially reverses the multidrug resistant phenotype. Rhodamine 123 studies are also consistent with an MDR-1 independent mechanism of increased drug efflux.

CONCLUSION

Together this data suggests that PGK1 can induce a multidrug resistant phenotype through an MDR-1 independent mechanism.

Fine-Needle Aspiration Biopsy in the Diagnosis and Classification of Primary and Recurrent Lymphoma: A Retrospective Analysis of the Utility of Cytomorphology and Flow Cytometry

We retrospectively reviewed our experience with the fine-needle aspiration biopsy (FNAB) diagnosis of primary and recurrent lymphoma to assess the ability of cytomorphology with and without ancillary flow cytometry (FCM) analysis to diagnose and subclassify these tumors according to the Revised European-American Lymphoma/World Health Organization classifications. We reviewed 139 consecutive FNABS of 84 primary and 55 recurrent lymphomas. FCM was successful in 105 (75%) cases. The overall results, including cases without FCM, included 93/139 (67%) true positive, 7 (5%) false negative, and 39 indeterminate (27 [19%] suspicious and 12 [9%] atypical) diagnoses of lymphoma. In cases with FCM, there were 80/105 (77%) true positive, no false negative, and 25 indeterminate diagnoses (15 [14%] suspicious and 10 [9%] atypical). The overall results of the 84 primary lymphomas were 55 (67%) true positive, 5 (5%) false negative, and 24 indeterminate (14[16%] suspicious and 10 [12%] atypical) diagnoses for lymphoma. Of the 68 primary lymphomas analyzed with FCM, 50 [74%] were true positives, and 28 were indeterminate (11 [16%] suspicious and 7 [10%] atypical). There were no false negatives. Diagnostic accuracy varied among lymphoma subtypes. Subclassification of the positive cases were initially conclusive in only 55/93 cases (59%). However, a retrospective review of the morphologic together with FCM data in 15 of the 23 unclassified cases improved the overall subclassification of positive cases to 77%. Subclassification was best in small lymphocytic lymphoma/chronic lymphocytic leukemia, lymphoplasmacytic lymphoma, Burkitt's lymphoma, mantle cell lymphoma, and plasmacytoma (all 100%). Subclassification was poor in marginal-zone lymphoma (33%), and initially as well in diffuse large B-cell lymphoma (62%), but it improved on review (95%), as did subclassification of follicular lymphoma (77 to 100% on review). Hodgkin's disease was recognized as malignant in only 44% of the cases (7/16) and was classified as such based on morphology alone. This review of our early efforts to diagnose and subclassify lymphoma with FNAB and FCM indicates that although a diagnosis and proper subclassification of lymphoma can be made with certainty in the majority of cases, recurrent or primary, it requires close coordination of cytomorphology and immunophenotyping data, which often comes with close cooperation of cytopathologists and hematopathologists. A mere cytological diagnosis of positive for lymphoma is no longer acceptable if FNAB is to become an independent diagnostic tool for lymphoma.

Pulsed electric fields for selection of hematopoietic cells and depletion of tumor cell contaminants

Purging of tumor cells and selection of stem cells are key technologies for enabling stem cell transplantation and stem cell gene therapy. Here we report a strategy for cell selection based on physical properties of the cells. Exposing cells to an external pulsed electric field (PEF) increases the natural potential difference across the cell membrane until a critical threshold is reached and pore formation occurs, resulting in fatal perturbation of cell physiology. Attaining this threshold is a function of the applied field intensity and cell size, with larger cells porated at lower field intensities than smaller cells. Since hematopoietic stem cells are smaller than other hematopoietic cells and tumor cells, we found that exposure of peripheral blood mononuclear cells (PBMCs) to PEFs caused stepwise elimination of monocytes without affecting the function of smaller lymphocyte populations. Mobilized peripheral blood exposed to PEFs was enriched for CD34+/CD38- cells and stem cell function was preserved. Furthermore, PEF treatment was able to selectively purge blood preparations of tumor cells and eradicate transplantable tumor.

Regulatory role of mature B cells in a murine model of inflammatory bowel disease

The spontaneous chronic colitis in TCR alpha mutant (TCRalpha(-/-)) mice mediated by CD4(+) TCRalpha(-)beta(+) T cells is more severe in the absence of mature B cells, suggesting a suppressive role of B cells and Ig in the development of chronic colitis. To investigate the direct role of B cells in the suppression of this colitis, cell transfer studies were performed in TCRalpha(-/-) x Igmu(-/-) (alphamu(-/-)) double-knockout mice. The chronic colitis was markedly attenuated in alphamu(-/-) mice after the adoptive transfer of peripheral B cells from TCRalpha(-/-) mice into 3- to 4-week-old alphamu(-/-) mice prior to the development of colitis. Furthermore, transfer of mature B cells from TCRalpha(-/-) mice markedly decreased the number of pathogenic colonic CD4(+) TCRalpha(-)beta(+) T cells in alphamu(-/-) mice with established colitis. This B cell effect required the presence of functional co-stimulatory molecules CD40 and B7-2 (CD86) but not B7-1 (CD80). These results indicate that mature B cells play an important role in the development of chronic colitis in TCRalpha(-/-) mice by directly regulating the pathogenic T cells (CD4(+) TCRalpha(-)beta(+) T cells).

Treatment of multiple myeloma by antibody mediated immunotherapy and induction of myeloma selective antigens

BACKGROUND

In view of the successful use of serotherapy in many B-cell malignancies, we and others have sought to identify tumor selective antigens for the serotherapy of plasma cell dyscrasias (PCD) including multiple myeloma (MM), and Waldenstrom's macroglobulinemia (WM). We recently identified Muc-1 core protein as a MM selective antigen. Though Muc-1 core protein is abundantly expressed on most MM plasma cells, expression of this antigen can be absent, or weak on some plasma cells which could potentially result in the selection of Muc-1 core protein negative clones following serotherapy of PCD. In addition to Muc-1 core protein, we have also been examining the use of CD20 directed serotherapy for PCD.

DESIGN

As part of these efforts, we recently initiated a phase II clinical trial examining the use of Rituximab (Rituxan, MabThera) as a single agent in MM patients; as well several WM patients have been treated with Rituximab at our Institutions.

RESULTS

In previous studies, we have shown that CD20 is abundantly expressed on the plasma cells of most WM patients; in contrast, CD20 is expressed on plasma cells from a minority of MM patients, and in these patients expression of CD20 can be weak or heterogeneous with both CD20+ and CD20- plasma cells present. As such, we have sought out clinically useful inducers of Muc-1 core protein, and of CD20 on malignant plasma cells.

CONCLUSIONS

These efforts resulted in the identification of dexamethasone (Dex) as a potent inducer of Muc-1 core protein on MM plasma cells, and interferon-gamma (IFN-gamma) as a potent inducer of CD20 on MM plasma cells and B-cells. Importantly, these agents induced their respective antigens at pharmacologically achievable doses.

In vitro priming with adenovirus/gp100 antigen-transduced dendritic cells reveals the epitope specificity of HLA-A*0201-restricted CD8+ T cells in patients with melanoma

Replication-deficient recombinant adenovirus (Ad) encoding human gp100 or MART-1 melanoma Ag was used to transduce human dendritic cells (DC) ex vivo as a model system for cancer vaccine therapy. A second generation E1/E4 region deleted Ad which harbors the CMV immediate-early promoter/enhancer and a unique E4-ORF6/pIX chimeric gene was employed as the backbone vector. We demonstrate that human monocyte-derived DC are permissive to Ad infection at multiplicity of infection between 100 and 500 and occurs independent of the coxsackie Ad receptor. Fluorescent-labeled Ad was used to assess the kinetics and distribution of viral vector within DC. Ad-transduced DC show peak transgene expression at 24-48 h and expression remains detectable for at least 7 days. DC transduced with replication-deficient Ad do not exhibit any unusual phenotypic characteristics or cytopathic effects. DC transduced with Ad2/gp100v2 can elicit tumor-specific CTL in vitro from patients bearing gp100+ metastatic melanoma. Using a panel of gp100-derived synthetic peptides, we show that Ad2/gp100v2-transduced DC elicit Ag-specific CTL that recognize only the G209 and G280 epitopes, both of which display relatively short half-lives ( approximately 7-8 h) on the surface of HLA-A*0201+ cells. Thus, patients with metastatic melanoma are not tolerant to gp100 Ag based on the detection of CD8+ T cells specific for multiple HLA-A*0201-restricted, gp100-derived epitopes.

Accumulation of macrophages with dendritic cell characteristics in the pulmonary response to Listeria

Pulmonary immunity reflects a balance between proinflammatory and immunosuppressive factors in the lung. To determine the immune activities of exudate macrophages in the pulmonary immune response, Lewis rats were injected intratracheally with heat-killed Listeria (HKL), labeled ex vivo with the lipophilic dye PKH-26. At 24 h, macrophages from bronchoalveolar lavage fluid were purified on the basis of their surface membrane expression of RMA, a macrophage-specific antigen, which is brightly expressed by resident alveolar macrophages but dimly expressed by monocytes. Pulmonary macrophages were analyzed for uptake of PKH-26-HKL, and RMA(bright/dim) macrophages sorted by FACS were compared for cytokine expression, nitric oxide (NO) release, and APC activities. RMA(bright) macrophages were OX-62(-), B7(-), and factor XIIIa(-); they were the dominant mediators of phagocytosis when low doses of HKL were administered intratracheally but did not support the proliferation of T lymphocytes. RMA(dim) exudate macrophages were OX-62(+), B7(+), and factor XIIIa(+). They expressed more IL-1 and TNF, but less nitric oxide, than did RMA(bright) macrophages; they were excellent APCs for T cell responses. We conclude that a subset of RMA(dim) exudate macrophages shows phenotypic and functional evidence of dendritic cell differentiation.

Cytokines IL-1beta, IL-2, IL-6, IL-8, MCP-1, GM-CSF and TNFalpha in patients with epithelial ovarian cancer and their relationship to treatment with paclitaxel

In vitro work suggests that cytokines may be important modulators of the cytotoxic effects of paclitaxel and subsequent drug resistance. This has been investigated in vivo in patients with ovarian cancer by ELISA. There was consistently elevated expression of IL-6 and IL-8 but not MCP-1, IL-1beta, IL-2, GM-CSF or TNFalpha. Peritoneal fluid concentrations of IL-6, IL-8 and MCP-1 were two to three logs greater than serum concentrations. Elevated concentrations of IL-6 correlated with a poor final outcome (P = 0.039), and increased IL-6 and IL-8 correlated with a poor initial response to chemotherapy (P = 0.041 and P = 0.041, respectively). There was a relatively clear pattern of change in all three cytokines. In serum, IL-6, IL-8 and MCP-1 decreased with the administration of steroids prior to paclitaxel, and increased in the 24 h after paclitaxel. Postoperative drainage fluid was relatively acellular, preventing flow-cytometric analysis of epithelial cells for apoptosis, but suggested activation of T cells by paclitaxel. IL-6 and IL-8 appear to be of prognostic importance in epithelial ovarian cancer. Treatment with paclitaxel is associated with an increase in expression of a limited number of cytokines in patients with ovarian cancer, notably IL-6, IL-8 and MCP-1.

Human ovarian cancer, cell lines, and primary ascites cells express the human Mullerian inhibiting substance (MIS) type II receptor, bind, and are responsive to MIS

Six human ovarian cancer cell lines and samples of ascites cells isolated from 27 patients with stage III or IV ovarian papillary serous cystadenocarcinoma were studied individually to test whether recombinant human Mullerian inhibiting substance (rhMIS) acts via its receptor. To do these experiments, we scaled up production of rhMIS and labeled it successfully with biotin for binding studies, cloned the human MIS type II receptor for mRNA detection, and raised antibodies to an extracellular domain peptide for protein detection. These probes were first tested on the human ovarian cancer cell lines and then applied to primary ovarian ascites cells. rhMIS inhibited colony growth of five of six cell lines that expressed the human MIS type II receptor mRNA by Northern analysis while not inhibiting receptor-negative COS cells. Flow cytometry performed on MIS-sensitive ovarian cancer cell lines demonstrated specific and saturable binding of rhMIS (Kd = 10.2 nM). Ascites cells from 15 of 27 or 56% of patients tested bound biotinylated MIS (MIS-biotin) and, of the 11 that grew in soft agarose, 9 of 11 or 82% showed statistically significant inhibition of colony formation. Of the 15 patients who bound biotinylated MIS, mRNA was available for analysis from 9, and 8 of 9 expressed MIS type II receptor mRNA by reverse transcription-PCR, showing a statistically significant correlation, compared with binding, by chi2 analysis (P = 0.025). Solid ovarian cancers were positive for the MIS type II receptor protein by immunohistochemical staining, which colocalized with staining for antibody to CA-125 (OC-125). Thus, the detection of the MIS type I receptor by flow cytometry may be a useful predictor of therapeutic response to MIS and may be a modality to rapidly choose patients with late-stage ovarian cancer for treatment with MIS.

Treatment of plasma cell dyscrasias by antibody-mediated immunotherapy

The use of serotherapy to treat patients with plasma cell dyscrasias (PCDs) has been sought by us and others. Candidate antigens that have been targeted or proposed for targeting in PCDs include the immunoglobulin idiotype, CD19, CD38, CD54, CD126, HM1.24, and Muc-1 core protein. Unfortunately, many of these antigens are not ideal for use in serotherapy since they are not selectively expressed, are either shed or secreted, or have not been fully characterized. Serotherapy with an anti-CD19 monoclonal antibody (B4) conjugated to a blocked ricin toxin had no significant activity in patients with multiple myeloma (MM). Circulating CD20+ clonotypic B cells have been detected in the circulation of most MM and Waldenstrom's macroglobulinemia (WM) patients. Plasma cells from most WM patients express CD20, but most MM patient plasma cells either lack CD20 or express it weakly. In view of recent successes with anti-CD20-directed serotherapy in other B-cell malignancies, we initiated a phase II trial to study the anti-CD20 monoclonal antibody rituximab (Rituxan; IDEC Pharmaceuticals, San Diego, CA, and Genentech, Inc, San Francisco, CA) in patients with MM. We describe two PCD patients (one with WM and one with MM) who responded to therapy. By flow cytometric analysis, CD20+ plasma cells and B cells present in the bone marrow and peripheral blood of a patient with MM disappeared with response to rituximab therapy. However, residual CD20- tumor cells remained in the bone marrow following rituximab therapy, and after 6 months this patient progressed with CD20- myeloma cells. As a potential strategy to overcome this limitation, we demonstrated that interferon-gamma at pharmacologically achievable levels induced CD20 expression on these CD20- plasma cells, consistent with our recent findings that interferon-gamma is a potent inducer of CD20 expression on MM patient plasma cells and B cells. We also characterize a response to rituximab with a decrease in paraprotein and resolution of anemia in a patient with WM whose response to rituximab is ongoing after 19+ months. This preliminary experience supports the potential use of serotherapy targeting CD20 in PCDs. Our studies further suggest that interferon-gamma may enhance CD20 expression on MM plasma cells, thereby increasing their susceptibility to anti-CD20 monoclonal antibody therapies.

Müllerian-inhibiting substance type II receptor expression and function in purified rat Leydig cells

Müllerian-inhibiting substance (MIS), a gonadal hormone in the transforming growth factor-beta superfamily, induces Müllerian duct involution during male sexual differentiation. Mice with null mutations of the MIS ligand or receptor develop Leydig cell hyperplasia and neoplasia in addition to retained Müllerian ducts, whereas MIS-overexpressing transgenic mice have decreased testosterone concentrations and Leydig cell numbers. We hypothesized that MIS directly modulates Leydig cell proliferation and differentiated function in the maturing testis. Therefore, highly purified rat Leydig and Sertoli cells were isolated to examine cell-specific expression, binding, and function of the MIS type II receptor. These studies revealed that this receptor is expressed abundantly in progenitor (21-day) and immature (35-day) Leydig cells as well as in Sertoli cells. Prepubertal progenitor Leydig cells exhibit high affinity (Kd = 15 nM), saturable binding of MIS. No binding, however, is detected with either peripubertal immature Leydig cells or Sertoli cells at either age. Moreover, progenitor, but not immature Leydig cells, respond to MIS by decreasing DNA synthesis. These data demonstrate that functional MIS type II receptors are expressed in progenitor Leydig cells and support the hypothesis that MIS has a direct role in the regulation of postnatal testicular development.

Intrinsic human immunodeficiency virus type 1 resistance of hematopoietic stem cells despite coreceptor expression

Interactions of human immunodeficiency virus type 1 (HIV-1) with hematopoietic stem cells may define restrictions on immune reconstitution following effective antiretroviral therapy and affect stem cell gene therapy strategies for AIDS. In the present study, we demonstrated mRNA and cell surface expression of HIV-1 receptors CD4 and the chemokine receptors CCR-5 and CXCR-4 in fractionated cells representing multiple stages of hematopoietic development. Chemokine receptor function was documented in subsets of cells by calcium flux in response to a cognate ligand. Productive infection by HIV-1 via these receptors was observed with the notable exception of stem cells, in which case the presence of CD4, CXCR-4, and CCR-5, as documented by single-cell analysis for expression and function, was insufficient for infection. Neither productive infection, transgene expression, nor virus entry was detectable following exposure of stem cells to either wild-type HIV-1 or lentivirus constructs pseudotyped in HIV-1 envelopes of macrophage-tropic, T-cell-tropic, or dualtropic specificity. Successful entry into stem cells of a vesicular stomatitis virus G protein-pseudotyped HIV-1 construct demonstrated that the resistance to HIV-1 was mediated at the level of virus-cell membrane fusion and entry. These data define the hematopoietic stem cell as a sanctuary cell which is resistant to HIV-1 infection by a mechanism independent of receptor and coreceptor expression that suggests a novel means of cellular protection from HIV-1.

Myeloperoxidase detection by three-color flow cytometry and by enzyme cytochemistry in the classification of acute leukemia

In the classification of acute leukemia, the presence of myeloperoxidase (MPO) within the leukemic blasts indicates myeloid leukemia. Previous studies compared enzyme cytochemistry (EC) or flow cytometry (FC) with immunocytochemistry, in detecting MPO. Our study is the first direct comparison of EC with 3-color FC in a large group of acute leukemias. We studied 26 cases of acute myeloid leukemia (AML) and 4 cases of B-precursor acute lymphoblastic leukemia (B-ALL). Classification was according to the French-American-British criteria. The cells were analyzed for MPO expression by 3-color FC after cell permeabilization followed by staining with anti-MPO antibody. For FC, the blasts were defined by a combination of light scatter characteristics and dim CD45 expression. Concordance between EC and FC was seen in 27 of 30 cases (23/26 AML and all B-ALL), including all AML cases of M1, M2, M3, and M4 subtypes. In 1 of 4 AML-MO and 2 of 5 AML-M5a cases, FC demonstrated the presence of MPO in 8%, 86%, and 94% blasts; EC detected none. Three-color FC may be more sensitive than routine EC in demonstrating the presence of MPO in AML cases and may offer the advantage of multiparametric analysis.

Humanized IgG1 and IgG4 anti-CD4 monoclonal antibodies: effects on lymphocytes in the blood, lymph nodes, and renal allografts in cynomolgus monkeys

BACKGROUND

Optimizing therapeutic monoclonal antibody (mAb) depends on the incorporation of the necessary effector functions and the development of hypoantigenic "humanized" antibodies by genetic engineering, which then need to be tested in appropriate preclinical trials.

METHODS

Constructs of humanized OKT4A containing the complementarity-determining region (CDR) of murine OKT4A and the framework and constant regions of human light (kappa) and heavy chains (IgG1 and IgG4) were prepared and tested in cynomolgus monkeys who received a renal allograft. A prophylactic course of CDR-OKT4A/human (h) IgG1 or CDR-OKT4A/ hIgG4, either as high-dose single bolus (10 mg/kg) or as low-dose multiple infusion (1 mg/kg for 12 days) was given, and the effects on graft survival, immunohistology, circulating cells, and lymph node cells were assessed.

RESULTS

The IgG1 isotype induced coating of T cells, modulation of surface CD4 molecules, and profound depletion of CD4+ lymphocytes in peripheral blood, which persisted as long as the animals were followed (up to 7 weeks). The IgG4 isotype induced only cell coating without cell clearance or modulation. In lymph nodes, coating of lymphocytes (approximately 60%) was seen with both isotypes in the earliest sample (6 hr). After 2 days, significant depletion of lymph node CD4 cells was evident, with a decrease in the CD4 to CD8 ratio in the IgG1-treated group; no depletion occurred in the IgG4 group. The emigration of CD4+ cells into the allograft was significantly delayed in the CDR-OKT4A/hIgG1-treated animals when compared with the CDR-OKT4A/hIgG4 group as judged by immunocytochemistry (23.8+/-13.2 days vs. 7.4+/-1.5 days, P<0.001) or interleukin-2-promoted T-cell outgrowth from allograft biopsies (22.2+/-11.0 days vs. 6.3+/-0.5 days, P<0.01).

CONCLUSIONS

This study demonstrates that the in vivo effects of CDR-grafted OKT4A are dependent on its isotype. The depleting mAb CDR-OKT4A/hIgG1 significantly delays the entry of CD4+ cells into the graft, inhibiting the early phase of rejection. However, graft rejection occurs when CD4+ cells eventually infiltrate the graft, even in the presence of depressed levels of circulating CD4+ cells. Both isotypes demonstrated therapeutic efficacy: graft survival was prolonged over controls. In the case of CDR-OKT4A/hIgG4, neither lymphocyte depletion, antigenic modulation, nor prevention of infiltration is necessary for a beneficial effect, which indicates that this mAb blocks CD4 function or renders the CD4+ cell less responsive. The lack of depletion is a feature of potential clinical advantage in minimizing the risk of excessive immunosuppression.

Suppressive role of B cells in chronic colitis of T cell receptor alpha mutant mice

The role of antibodies (Abs) in the development of chronic colitis in T cell receptor (TCR)-alpha-/- mice was explored by creating double mutant mice (TCR-alpha-/- x immunoglobulin (Ig)mu-/-), which lack B cells. TCR-alpha-/- x Ig mu-/- mice spontaneously developed colitis at an earlier age, and the colitis was more severe than in TCR-alpha-/- mice. Colitis was induced in recombination-activating gene-1 (RAG-1-/-) mice by the transfer of mesenteric lymph node (MLN) cells from TCR-alpha-/- x Ig mu-/- mice. When purified B cells from TCR-alpha-/- mice were mixed with MLN cells before cell transfer, colitis did not develop in RAG-1-/- mice. Administration of the purified Ig from TCR-alpha-/- mice and a mixture of monoclonal autoAbs reactive with colonic epithelial cells led to attenuation of colitis in TCR-alpha-/- x Ig mu-/- mice. Apoptotic cells were increased in the colon, MLN, and spleen of TCR-alpha-/- x Ig mu-/- mice as compared to Ig mu-/- mice and TCR-alpha-/- mice. Administration of the purified Ig from TCR-alpha-/- mice into TCR-alpha-/- x Ig mu-/- mice led to decrease in the number of apoptotic cells. These findings suggest that although B cells are not required for the initiation of colitis, B cells and Igs (autoAbs) can suppress colitis, presumably by affecting the clearance of apoptotic cells.

In vitro detection of Mycoplasma fermentans binding to B-lymphocytes in fresh peripheral blood using flow cytometry

Previous reports have shown, using fluorescent probes conjugated to the organism, that Mycoplasma fermentans fuses with about 12% of peripheral blood lymphocytes. However, no lymphocyte subset was specified. To elucidate the specific subset of lymphocytes involved, we developed a three-color flow cytometric assay to detect M. fermentans binding to fresh peripheral blood cells. In our assay, two strains of M. fermentans were grown in SP4 glucose broth, mixed with fresh whole blood samples (n > 20), and incubated at 37 degrees C. The blood samples were then stained with a polyclonal antibody to M. fermentans, a monoclonal antibody to B-lymphocytes (CD19), and a monoclonal antibody to T-lymphocytes (CD3). Using three-color flow cytometry, we obtained data confirming binding of M. fermentans to 10%-15% of peripheral blood lymphocytes with minimal granulocyte or monocyte staining detected. Flow cytometric analysis showed that early binding appears predominantly directed towards B-lymphocytes (86.7 +/- 9.0%), and that this binding could not be blocked by antibodies directed towards common B lymphocyte cell surface antigens. M. fermentans binding to B-lymphocytes occurred within 5 min of in vitro inoculation, reached a maximum within 30-60 min (94-97%), and thereafter plateaued. The binding was concentration dependent over a three log dilution using 10(3) color changing units as standard. Binding to T-lymphocytes was minimal (<5% positive). B lineage tumor cells or peripheral blood B cells obtained from HIV infected individuals demonstrated reduced binding of M. fermentans. This assay provides a good method to study the cellular interactions of mycoplasma and may help to elucidate pathogenic mechanisms of mycoplasma infections.

Cytotoxicity and apoptosis in human renal allografts: identification, distribution, and quantitation of cells with a cytotoxic granule protein GMP-17 (TIA-1) and cells with fragmented nuclear DNA

In the present study, we analyzed human renal allografts using immunohistochemical techniques to determine the site, identity, and frequency of (a) cytotoxic and apoptotic cells, as identified by staining for GMP-17 (TIA-1), a component of cytotoxic granules; and (b) DNA fragmentation in situ, as detected by the TUNEL method. In acute cellular rejection (n = 15), GMP-17+ mononuclear cells accounted for 29% +/- 12% of the infiltrating cells in the interstitium (341 +/- 164/mm2) and were significantly more concentrated in tubulitis lesions, where they amounted to 65% +/- 14% of the mononuclear cells (96 +/- 61/mm2) (p < 0.01 versus interstitium). GMP-17+ mononuclear cells were also found in sites of endothelialitis. An estimated 80% of the GMP-17+ lymphocytes expressed CD8, and 10% to 20% expressed either CD4 or the macrophage marker CD14. The latter finding led us to analyze normal peripheral blood monocytes by flow cytometry, all of which were found to contain GMP-17. NK cells and neutrophils, which are known to express GMP-17, were detected only rarely in allografts. Specimens with cyclosporine A toxicity (n = 7) or acute tubular necrosis (n = 13) showed fewer GMP-17+ cells in the interstitium (22 +/- 46/mm2 and 62 +/- 50/mm2, respectively) and tubules (2 +/- 6/mm2 and 10 +/- 10/mm2, respectively) (all p < 0.01 versus rejection). These differences were due largely to less intense mononuclear cell infiltration. In cyclosporine A toxicity, however, the percentages of GMP-17+ mononuclear cells within tubules and the interstitium were significantly lower than in rejection (p = 0.02), whereas in acute tubular necrosis significantly lower percentages were found in the tubules (p = 0.04) but not in the interstitium. Native kidneys with end-stage diabetic nephropathy (n = 5) had very low proportions of GMP-17+ cells in interstitial infiltrates (7% +/- 6%) and in tubules (11% +/- 15%), although the infiltrates were focally intense (517 +/- 355/mm2). TUNEL+ cells were found in acute cellular rejection, predominantly in areas with intense mononuclear infiltrates and also within lesions of tubulitis and endothelialitis. Although some TUNEL+ cells were intrinsic renal cells, most appeared to be infiltrating mononuclear cells, and we were able to detect CD3 in some. In areas of intense cellular infiltration, the percentages of TUNEL+ cells (range, 0.5% to 4.2%) were comparable to those seen in the rat thymus, indicating a high level of apoptosis. Overall, in the allograft samples, the numbers of GMP-17+ cells and TUNEL+ cells were significantly correlated (r = 0.79; p < 0.01). These data provide new evidence that T cell (and possibly macrophage)-mediated cytotoxicity plays an important role in acute renal allograft rejection, particularly in the case of tubular injury, and furthermore suggest that apoptosis may be a mechanism not only for graft cell destruction, but also for elimination of activated T cells in the infiltrate.

Reduced fatty acid ethyl ester synthase activity in the white blood cells of alcoholics

PURPOSE

Fatty acid ethyl esters (FAEEs), esterification products of ethanol and fatty acids, have been implicated as mediators of ethanol-induced organ damage. It has been shown that FAEE synthase, the enzyme responsible for the formation of FAEE, is present selectively in the organs commonly damaged by ethanol abuse. Recently, we have made the observation that FAEEs are also present in the serum after ethanol ingestion. The current study was performed to determine whether cellular elements of the blood and/or plasma are capable of synthesizing FAEEs from fatty acids and ethanol.

MATERIALS AND METHODS

Heparinized blood samples were collected from 10 healthy volunteers, and the red blood cells, platelets, plasma, and several white blood cell populations were assayed for FAEE synthase activity. Blood samples from control subjects and individuals admitted to an alcoholic detoxification unit at a local hospital were also assayed for FAEE synthase activity.

RESULTS

We observed that the FAEE synthase activity is present in whole blood, primarily within white blood cells. Fractionation of the white blood cells revealed that the lymphocyte-monocyte fraction isolated using Ficoll-hypaque contained approximately 3.5-fold higher activity than the granulocyte fraction. The cell type that contained the highest FAEE synthase activity (1220 pmol/hr/10(6) cells) was the natural killer (NK) cell population. B cells contained approximately 40% of the enzyme activity found in NK cells, and the B-cell activity was slightly greater than that found in CD4+ and CD8+ T cells. Having shown that FAEE synthase exists in a blood cell, we subsequently demonstrated that alcoholic individuals have approximately half the white blood cell FAEE synthase activity of that found in normal controls. We also demonstrated that white blood cell FAEE synthase could be induced nearly 2-fold upon ingestion of 2 oz of scotch whiskey for 6 days. The enzyme activity returned to baseline levels despite ingestion of 2 oz of scotch whiskey/day for 3 additional days.

CONCLUSIONS

These data indicate that ethanol ingestion results in increased FAEE production, particularly by NK cells. FAEE synthesis after ethanol ingestion may explain the presence of FAEE in the serum. The lower enzyme activity observed in white blood cells of alcoholics from a detoxification center may be the result of years of ethanol abuse or it may be that alcoholics congenitally have low levels of FAEE synthase. If the latter is true, this finding may explain in part the genetic predisposition of many alcoholic individuals to ethanol abuse.

Flow cytometric analysis of DNA ploidy, percent S-phase fraction, and total proliferative fraction as prognostic indicators of local control and survival following radiation therapy for prostate carcinoma

PURPOSE

Treatment recommendations for localized prostate cancer may be improved by the identification of tumor factors prognostic for local control and survival. In this retrospective study, flow cytometric deoxyribonucleic acid (DNA) ploidy analysis and cell cycle analysis were performed on paraffin-embedded biopsy material to determine if additional prognostic factors could be identified in patients treated with radiation therapy.

METHODS AND MATERIALS

Seventy patients with T1-4NxM0 tumors were identified in whom the primary treatment had been radical radiation therapy with no prior or concurrent endocrine therapy and in whom sufficient prostatic tissue was available for flow cytometric analysis. There were 40 diploid, 26 aneuploid, and 4 multiploid cases. Aneuploid and multiploid cases were combined for analysis. Cell cycle data were obtained on all diploid and 10 aneuploid cases.

RESULTS

The histologic differentiation of the tumor (well or moderate vs. poor) was an independent predictor of overall survival and disease-free survival (p = 0.05 and 0.01, respectively). Local control was worse in the poorly differentiated patients, although this was not statistically significant in a multivariate analysis (p = 0.08). Neither T-stage, deoxyribonucleic acid ploidy (diploid vs. nondiploid), percent S-phase fraction, nor total proliferative fraction (S-phase fraction + G2M) significantly predicted for any of these endpoints. Within the diploid and well or moderately differentiated subgroup (n = 25), S-phase (< 4.2 vs. > or = 4.2) was a significant predictor of local control (100% vs. 51%, p = 0.03). A comparable distinction could be made using total proliferative fraction (< 10% vs. > or = 10%) with local control rates of 100% vs. 56% (p = 0.05). Among the poorly differentiated tumors, no similarly favorable subgroup was identified.

CONCLUSIONS

This retrospective and multivariate analysis identifies both histology and percent S-phase or total proliferative fraction as predictors of local control following irradiation, and confirms that histology, but not DNA ploidy, is significant for overall survival. If these previously unreported findings are confirmed by prospective studies, S-phase should be added to histology as a parameter in the evaluation of clinical trials.

A comparative study of flow cytometry and histopathologic findings in thyroid follicular carcinomas and adenomas

As a possible diagnostic aid in the often difficult histopathologic distinction of thyroid follicular carcinomas from adenomas based on invasion most flow cytometry studies have indicated a higher aneuploidy incidence in carcinomas. However, these reports often are difficult to analyze mainly due to nonuniformity of pathologic diagnostic criteria. The present study compares the flow cytometry results of 65 follicular tumors with pathologic findings based on the World Health Organization's specific diagnostic and staging criteria. Aneuploidy was significantly higher in the 28 cancers than in the 27 hypercellular (fetal and embryonal) adenomas (57% v 22%; P = .02). There was a high percentage of aneuploidy (75%; nine of 12 cases) in the widely invasive follicular carcinomas, compared with 40% (six of 15 cases) in the minimally invasive carcinomas, 22% (six of 27 cases) in the hypercellular adenomas, and 10% (one of 10 cases) in the normofollicular or macrofollicular adenomas. However, aneuploidy was not significantly different between the most difficult differential histopathologic diagnoses of minimally invasive follicular carcinoma (40%; six of 15 cases) and hypercellular adenoma (22%; six of 27 cases) (P = .12). Other data included relatively high frequencies of aneuploidy in hypercellular adenomas (29%; six of 21 cases) and diploid status of carcinomas (36%; 12 of 33 cases). In summary, although the overall findings show a trend toward increasing aneuploidy from well-differentiated and hypercellular adenomas to minimally and widely invasive follicular carcinomas, the aneuploidy data are inconsistent and indicative of its nonspecificity and limited diagnostic usefulness.

The AgNOR technique, PCNA immunohistochemistry, and DNA ploidy in the evaluation of choroid plexus biopsy specimens

The histologic distinctions between normal choroid plexus and choroid plexus papilloma and between choroid plexus papilloma and choroid plexus carcinoma are sometimes difficult. The authors performed the silver nucleolar organizer region (AgNOR) technique, immunohistochemistry for proliferating cell nuclear antigen (PCNA), and DNA ploidy analysis by flow cytometry on 9 samples of normal choroid plexus, 8 papillomas, and 13 carcinomas to evaluate whether these techniques can aid in these differential diagnoses. Significant differences were found in the mean AgNOR count between normal choroid plexus (1.35 +/- 0.11) and choroid plexus papillomas (2.42 +/- 0.81) (P < 0.001), but not between choroid plexus papillomas and carcinomas. In the normal choroid plexus, AgNORs were smooth and round; in the papillomas and carcinomas, however, they varied in size and shape. Compound AgNORs were commonly present in the tumors but were essentially absent in controls. Antibody to PCNA did not stain normal choroid plexus cells (except for focal staining in one sample of normal choroid plexus adjacent to a carcinoma) but stained many papilloma and carcinoma cells. DNA ploidy analysis demonstrated aneuploidy in some papillomas and carcinomas but could not be used for the distinction of normal choroid plexus from papillomas. These results suggested that the AgNOR technique and PCNA immunohistochemistry could be used to distinguish normal choroid plexus from choroid plexus papilloma in small, diagnostically difficult biopsy specimens.

A phase I trial of immunosuppression with anti-ICAM-1 (CD54) mAb in renal allograft recipients

Several adhesion molecules contribute to the interaction between T cells and antigen presenting cells or target cells. Leukocyte function-associated molecule-1 (LFA-1[CD11a/CD18]) and intercellular adhesion molecule-1 (ICAM-1 [CD54]) are one such critical adhesive receptor-counter-receptor combination. The importance of ICAM-1 dependent adhesion in the rejection response was initially demonstrated in cynomolgus renal allograft recipients treated with the anti-ICAM-1 murine monoclonal antibody BIRR1. BIRR1 also appeared to limit ischemic damage in these animals. A Phase I clinical trial has subsequently been completed in 18 patients who received cadaver donor renal allografts at high risk for delayed graft function (prolonged preservation time, highly-sensitized recipient). An adequate BIRR1 serum level was associated with significantly less delayed graft function (P < .01) and rejection (P < .01). In 1-hr biopsies, mouse IgG was detected along the endothelium of the vessels and glomeruli in the graft. There were no instances of primary non-function (PNF), and current allograft survival (followup: 16-30 months) in these "high-risk" mAb-treated patients is 78%. There were 3 instances of PNF and a graft survival rate of 56% in the recipients of the contralateral kidney allografts treated with conventional immunosuppression. No significant "first-dose" effect was associated with BIRR1 administration. These results establish a dosing schedule and the clinical safety of BIRR1. They also suggest that inhibition of leukocyte adhesion by mAb therapy may be useful in controlling allograft rejection and possibly in limiting reperfusion injury. Thus, these observations support the clinical importance of accessory molecules in T cell function. We hypothesize that anti-CD54 mAb acts by blocking leukocyte adhesion to the endothelium, thereby interfering with sensitization or target cell interaction.

Identification of müllerian inhibiting substance specific binding in human cell lines

The receptor for Müllerian Inhibiting Substance (MIS), a gonadal glycoprotein hormone, has not been previously identified. Plasma membranes from MIS-sensitive human tumor cell lines (HTB-111, endometrial carcinoma; and A-431, vulvar squamous carcinoma) were detergent extracted and incubated with 125I-labeled MIS anti-idiotypic antibody, or radioiodinated human recombinant MIS (125I rhMIS), with and without unlabeled competitors. 125I anti-idiotypic MIS antibody bound to HTB-111 membrane extracts was displaceable by unlabeled anti-idiotypic antibody, but not by anti-isotypic antibody prior to cross-linking. Specific binding of the anti-idiotypic MIS antibody to endometrial carcinoma cells was verified using fluorescence activated cell analysis and fluoresceinated antibody. Furthermore, unlabeled anti-idiotypic MIS antibody competed for 125I rhMIS binding to A-431 vulvar carcinoma membranes. The labeled anti-idiotypic MIS antibody binding complex could be separated from 32P labeled EGF receptor in the A-431 membranes, indicating that EGF, a natural inhibitor of MIS activity, and MIS itself bind to different receptors. These studies demonstrate a specific, displaceable binder for MIS in the plasmalemmae of two human tumor lines. Purification of this cell surface receptor protein will be greatly aided by using the MIS anti-idiotypic antibody.

Occurrence of melanoma in "dysplastic" nevus spilus: report of case and analysis by flow cytometry

We report a case of melanoma arising in a large nevus spilus. On histologic examination, the nevus spilus had diagnostic features of melanocytic dysplasia. Further characterization by flow cytometry showed DNA-aneuploidy within the melanoma as well as in one of the darker pigmented papules within the nevus spilus. The significance of this finding and a review of melanomas originating in nevi spili are presented.

Deoxyribonucleic acid flow cytometry in invasive bladder carcinoma: a possible predictor for successful bladder preservation following transurethral surgery and chemotherapy-radiotherapy

Tumor deoxyribonucleic acid (DNA) ploidy was evaluated as an objective parameter that may correlate better with the responsiveness of bladder cancer to chemotherapy plus radiotherapy than do clinical features or histopathological subtypes. A total of 40 patients with localized muscle-invading bladder cancer (clinical stages T2 to T4) underwent prospective treatment on a potential bladder preserving protocol. Tumors of 37 of the 40 patients were analyzed by DNA flow cytometry of multiple paraffin embedded specimens. Transurethral resection, neoadjuvant chemotherapy and 40 Gy. radiotherapy plus cisplatin were followed by urological reevaluation of the tumor (a complete response required a negative biopsy and a negative urine cytology study). A total of 7 noncomplete response patients underwent immediate radical cystectomy whereas the full bladder sparing treatment (radiotherapy to 64.80 Gy. plus cisplatin) was given to 23 complete response patients and 7 noncomplete response patients who were unsuited for surgery. Of the tumors 22 (59%) were purely aneuploid and 10 (27%) were purely diploid. Five tumors contained aneuploid and diploid patterns in different tumor specimens (partly diploid). Current status with a 30-month median followup in surviving patients includes an 82% overall survival rate in the aneuploid group versus 47% in the diploid/partly diploid group. Of all the patients 68% are free of invasive tumor: 82% in the aneuploid group versus 47% in the diploid/partly diploid group. By multivariate analysis pure aneuploidy was significantly (p = 0.05) correlated with freedom from invasive tumor in the bladder (either as persistence or as recurrence) and approached significance (p = 0.08) in correlation with overall patient survival. A longer observation time will be required to confirm this unexpectedly good outcome for patients with pure aneuploid tumors. We hypothesize that pretreatment DNA ploidy status may become a clinically useful prognostic factor in selecting patients for successful treatment with transurethral surgery and neoadjuvant chemotherapy plus radiotherapy.

The effects of OKT4A monoclonal antibody on cellular immunity of nonhuman primate renal allograft recipients

Significant differences in cellular responses were found among allograft recipients treated with various OKT4A mAb protocols. Recipients of multiple infusion low-dose and 2-bolus OKT4A immunosuppressive regimens regularly showed potent donor-specific cytotoxic CD8+ and CD4+ intragraft T cells and donor-reactive PBMC in MLC tests. In contrast, PBMC isolated from recipients of high-dose OKT4A therapy generally showed very weak or no response to donor-antigens during the later posttransplant periods. Furthermore, an absence of IL2-responsive intragraft cells was found to correlate with stable graft function in these recipients. We conclude that OKT4A mAb, in high doses, can block allosensitization and induce donor-specific nonresponsiveness in vivo. An OKT4A-based therapy, therefore, may have the potential of inducing long-lasting donor-specific immunosuppression, or even tolerance.

Most human pulmonary infiltrating lymphocytes display the surface immune phenotype and functional responses of sensitized T cells

Pulmonary infiltrating lymphocytes (PIL) isolated directly from human lung were examined for their surface immune phenotype by monoclonal antibody staining and cytofluorimetry. In order to purify PIL, resected lungs were enzymatically digested with collagenase and DNase and subjected to density centrifugation and nylon-wool column separation. In some cases, CD4+ lymphocytes were further purified with alpha CD8 and complement. The majority of pulmonary lymphocytes were CD2+ (87 +/- 1%) and CD3+ (73 +/- 4%). Virtually all of the CD3+ PIL were Ti alpha beta+. Greater than 90% of both CD4+ or CD8+ PIL were CD45RO+ and CD45RA-, consistent with prior antigen sensitization in vivo. A subset of CD4+ PIL (34 +/- 4%) expressed Leu8, the human congener of the murine MEL-14 lymphocyte homing receptor, whereas most homologous CD4+ peripheral blood lymphocytes were Leu8+ (75 +/- 8; P less than 0.01). HLA-DR surface antigens were expressed by 45 +/- 5% of CD4+ PIL versus 9 +/- 1% of CD4+ peripheral blood lymphocytes (P less than 0.001). There was no significant difference in the percentage of low-affinity interleukin-2 (IL-2) receptor-positive CD4+ lymphocytes in lung and blood (9 +/- 3% versus 13 +/- 2%). Analysis of the DNA synthetic cell cycle showed that approximately 5% of blood CD4+ lymphocytes and approximately 25% of CD4+ PIL were in S/G2/M. Compared to homologous blood T cells, purified PIL displayed enhanced proliferative responses to IL-2 and diminished responses to the lectin phytohemagglutinin. Lectin-stimulated PIL showed greater secretion of interferon-gamma and IL-2 than did blood lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Laboratory monitoring of therapy with OKT3 and other murine monoclonal antibodies

The first monoclonal antibody (MAb) approved by the Food and Drug Administration (FDA) for therapeutic use, OKT3, is now a standard treatment for organ allograft rejection. This article reviews the interpretation of laboratory tests used to manage patients treated with MAb. Emphasis is placed on OKT3, with which the experience is also the greatest, although comparisons with other MAbs in clinical trials is also discussed.

Prolonged survival of nonhuman primate renal allograft recipients treated only with anti-CD4 monoclonal antibody

The immunosuppressive efficacy of the monoclonal antibody OKT4A reactive with human and monkey CD4 cells was evaluated in cynomolgus renal allograft recipients. Low-dose (0.1 to 0.3 mg/kg/day) intact monoclonal antibodies (10 recipients) or F(ab')2 fragments (two recipients) were administered for 12 days. High-dose OKT4A (10 mg/kg) was administered on the day of transplantation as the only suppression in five animals. Four control animals received either no therapy or a monoclonal antibody nonreactive with monkey cells (OKT3). Maximum survival of the control animals and those treated with F(ab')2 was 11 days. Mean survival in the recipients of low-dose OKT4A was 25.4 +/- 4.3 days and in the group receiving high-dose OKT4A it was 39 +/- 6.4 days. All OKT4A-treated animals showed "coating" and CD4 modulation without depletion of circulating T cells. No modulation occurred in the F(ab')2-treated recipients. Serial allograft biopsy specimens showed reduced lymphocyte infiltration that was nearly complete in recipients of high-dose OKT4A. Biopsy-derived donor-reactive cytotoxic T-cell lines were generated regularly from recipients of low-dose, but not high-dose, OKT4A during periods of stable function. All animals treated with monoclonal antibodies developed an immunoglobulin G antimurine humoral response. Thus OKT4A is a potent immunosuppressive agent administered even as a single bolus, and depletion of CD4 cells is not required to suppress rejection. Anti-CD4 monoclonal antibodies may prove useful in patients, perhaps requiring only a limited number of higher-dose injections in the peritransplant period.

In vivo effects of monoclonal antibody to ICAM-1 (CD54) in nonhuman primates with renal allografts

These studies test whether allograft rejection can be blocked by interference with leukocyte adhesion, using a murine IgG2a mAb (R6.5) reactive with monkey ICAM-1 (CD54). In 16 Cynomolgus renal allograft recipients, R6.5 was administered prophylactically as the sole immunosuppressive agent for 12 days (0.01 to 2 mg/kg/day). Survival in 14 recipients with technically successful grafts was significantly prolonged (24.2 +/- 2.4 vs 9.2 +/- 0.6 days for controls; p less than 0.001). Intercellular adhesion molecule-1 (CD54) (ICAM-1) was expressed on vascular endothelium in the kidney and other organs in the monkey in a pattern similar to that in humans. During cellular rejection in controls, ICAM-1 expression increased on endothelial cells, infiltrating mononuclear leukocytes and tubular cells. Biopsies during R6.5 administration showed decreased T cell infiltration (CD2, CD8, CD4) compared with controls and decreased arterial endothelial inflammation. No changes occurred in circulating T cells, aside from variable coating with mIgG. In six of eight other recipients R6.5 administration (0.5 to 2 mg/kg/day for 10 days) reversed preexisting rejection that resulted from taper of Cyclosporine to subtherapeutic levels. Responding grafts showed decreased edema and hemorrhage but no consistent change in the infiltrate. At 1 h after the first dose, mouse IgG deposited primarily on the graft vascular endothelium without any change in the inflammatory infiltrate. Mouse IgG also deposited on the endothelium of normal organs without eliciting an inflammatory response and was cleared from the endothelium within 4 days. Inasmuch as the principal site of binding was the vascular endothelium, we hypothesize that the antibody blocks adhesion to graft ICAM-1 molecules on the vessels. Anti-ICAM-1 also binds to recipient cells and may interfere with Ag presentation and/or T cell interactions. Whatever the mechanism(s), these studies indicate that an anti-ICAM-1 antibody inhibits T cell mediated injury in vivo, and that ICAM-1 is a critical molecule in the pathogenesis of allograft rejection.

In vivo effects of monoclonal antibody to ICAM-1 (CD54) in nonhuman primates with renal allografts

These studies test whether allograft rejection can be blocked by interference with leukocyte adhesion, using a murine IgG2a mAb (R6.5) reactive with monkey ICAM-1 (CD54). In 16 Cynomolgus renal allograft recipients, R6.5 was administered prophylactically as the sole immunosuppressive agent for 12 days (0.01 to 2 mg/kg/day). Survival in 14 recipients with technically successful grafts was significantly prolonged (24.2 +/- 2.4 vs 9.2 +/- 0.6 days for controls; p less than 0.001). Intercellular adhesion molecule-1 (CD54) (ICAM-1) was expressed on vascular endothelium in the kidney and other organs in the monkey in a pattern similar to that in humans. During cellular rejection in controls, ICAM-1 expression increased on endothelial cells, infiltrating mononuclear leukocytes and tubular cells. Biopsies during R6.5 administration showed decreased T cell infiltration (CD2, CD8, CD4) compared with controls and decreased arterial endothelial inflammation. No changes occurred in circulating T cells, aside from variable coating with mIgG. In six of eight other recipients R6.5 administration (0.5 to 2 mg/kg/day for 10 days) reversed preexisting rejection that resulted from taper of Cyclosporine to subtherapeutic levels. Responding grafts showed decreased edema and hemorrhage but no consistent change in the infiltrate. At 1 h after the first dose, mouse IgG deposited primarily on the graft vascular endothelium without any change in the inflammatory infiltrate. Mouse IgG also deposited on the endothelium of normal organs without eliciting an inflammatory response and was cleared from the endothelium within 4 days. Inasmuch as the principal site of binding was the vascular endothelium, we hypothesize that the antibody blocks adhesion to graft ICAM-1 molecules on the vessels. Anti-ICAM-1 also binds to recipient cells and may interfere with Ag presentation and/or T cell interactions. Whatever the mechanism(s), these studies indicate that an anti-ICAM-1 antibody inhibits T cell mediated injury in vivo, and that ICAM-1 is a critical molecule in the pathogenesis of allograft rejection.

Fc-receptor for mouse IgG1 (Fc gamma RII) and antibody-mediated cell clearance in patients treated with Leu2a antibody

A pilot study was performed to explore the clinical potential of Leu2a antibody in reversing acute renal allograft rejection. Anti-Leu2a, a murine IgG1 monoclonal antibody (mIgG1 mAb), is specific for the CD8 molecule that is expressed in high density on class I reactive T cells. Of the 6 recipients treated with anti-Leu2a, two responded with a complete reversal of rejection with long-term allograft function maintained for over a year. In two other recipients, acute rejection was initially reversed, but later rejection episodes resulted in allograft failure at 2-3 months posttreatment. Rejection in the two other recipients showed no response to Leu2a mAb treatment. Specific depletion of peripheral blood CD8+ cells occurred in four of the six recipients. Even in this small series, it was evident that cell clearance was neither necessary nor sufficient for reversal of rejection. However, a complete correspondence between cell clearance and the ability of the recipients' mononuclear cells to undergo mitogenic response to the mIgG1 anti-CD3 (Leu4) mAb in vitro was noted. Binding of IgG1 mAb to the Fc-receptor (Fc gamma RII/CD32) expressed on blood monocytes is known to be essential for the T cell mitogenic response to soluble mIgG1 CD3 mAb in vitro. Our data suggest that binding to Fc gamma RII may be an essential step in the process of mIgG1 Leu2a mAb-mediated cell clearance in vivo.

A critical analysis of serum and urine interleukin-2 receptor assays in renal allograft recipients

A component of the interleukin 2 receptor (IL-2R) is released in soluble form during T cell activation and can be detected in the blood during acute renal allograft rejection. This study evaluates the diagnostic utility of a sandwich enzyme immunoassay test for serum and urine IL-2R in renal allograft recipients. A rise in serum IL-2R during the week prior to the clinical diagnosis of rejection correlated better with rejection than did isolated serum IL-2R levels or urine values. For the diagnosis of acute rejection, a rise in serum IL-2R (sensitivity 73%, specificity 87%) was comparable in overall test performance to a rise in serum creatinine (sensitivity 70%, specificity 84%). Overall, the two tests had equivalent receiver operating characteristic curves. Because the etiology of false positives in creatinine and IL-2R assays differed (primarily cyclosporine toxicity and infection, respectively), the predictive value of the combined tests was superior to either alone.

Identification of pre-T cells in human peripheral blood. Extrathymic differentiation of CD7+CD3- cells into CD3+ gamma/delta+ or alpha/beta+ T cells

CD7+CD3- cells purified (greater than 99.99%) by FACS from the peripheral blood of healthy adults include precursors for mature T cells that have the capacity to differentiate into TCR-1+ or TCR-2+ CD3+ cells. Extrathymic differentiation was demonstrable from all eight healthy donors in the presence of a high concentration of IL-2, mitogenic levels of PHA, and irradiated blood mononuclear feeder cells, after a lag of approximately 40 d in vitro. The extrathymic T (ET) cells were predominantly TCR-1+, although TCR-2+ cells were also derived. ET TCR-1+ cells were CD4-CD8-, CD4-CD8DIM+, and CD4+CD8-, and were distinguished from natural T TCR-2+ cells by a variety of cell surface markers. The ET cells had phenotypes generally displayed by normal mature T cells, although the CD5DIM+ on ET cells was more typical of thymocytes. Acquisition of CD3 on purified CD7+CD3- cells was not due to antigenic modulation or growth of contaminants, and ET cells could be demonstrated at the clonal level. Studies in athymic mice and bone marrow recipients support the view that extrathymic maturation does occur in vivo. Whether the CD7+CD3- cell population was unexposed to the thymus, or exposed but not processed, is unknown. In any case, unusual or "forbidden" autoreactive specificities are predicted since ET cells differentiate without thymic selection of the TCR.

Tumour-infiltrating lymphocytes and interleukin-2 in treatment of advanced cancer

Tumour-infiltrating lymphocytes (TIL) were isolated and expanded from small tumour biopsy samples of twenty-eight patients (thirteen with malignant melanoma, seven with renal cell carcinoma, and eight with non-small-cell lung cancer). The patients were treated with autologous expanded TIL (about 10(10)) and continuous infusions of recombinant human interleukin-2(1-3 x 10(6) U/m2 per 24 h). 29% of the patients with renal cell cancer and 23% of those with melanoma achieved objective tumour responses lasting 3-14 months. Toxic side-effects were limited, and no patient required intensive-care monitoring. Adoptive immunotherapy with TIL and interleukin-2 may be an effective systemic approach to the treatment of some patients with malignant melanoma and renal cell carcinoma.

Adoptive immunotherapy with IL-2 results in the loss of delayed-type hypersensitivity responses and the development of immediate hypersensitivity to recall antigens

Skin testing represents a direct method of assessing immune responses in vivo. Twenty-six patients with metastatic cancer of the lung, kidney, or melanoma were treated with adoptive transfers of autologous tumor-infiltrating or blood lymphocytes and continuous infusions of interleukin-2 (IL-2). Prior to therapy, cutaneous anergy to recall antigens was observed in 19 patients (73%), whereas 6 (27%) displayed normal delayed-type hypersensitivity (DTH) responses. When tested again at the end of therapy, DTH responses could not be elicited in any of the patients. Proliferative responses to skin test antigens, lectins, and IL-2 diminished progressively during therapy but returned to baseline values at 1 month. Unexpectedly, 14 of these patients (53%) developed immediate skin test responses to candida antigens and 5 (19%) to mumps antigens. These immediate responses were characterized by local erythema and induration that developed within minutes of injecting antigen. Biopsies displayed marked dermal edema and infiltration by eosinophils. Although serum IgE levels were not increased, immediate reactivity could be transferred by a heat-sensitive serum factor. The implications of this novel response are uncertain, and its development did not correlate directly with the anti-tumor effects of therapy. We conclude that adoptive immunotherapy with IL-2 produces a reduction in cutaneous DTH and diminished responses to mitogens while simultaneously promoting cutaneous allergy. We hypothesize that this may reflect diminished IL-2 production by antigen-specific helper T cells and that other lymphokines may promote these immediate hypersensitivity responses.

Changes in bromodeoxyuridine labeling index during radiation treatment of an experimental tumor

Cell proliferation kinetics in a spontaneous mouse fibrosarcoma (FSaII) growing in C3H mice has been studied by in vivo pulse labeling of cells synthesizing DNA with bromodeoxyuridine (BrdUrd). A monoclonal antibody to BrdUrd and flow cytometry were used to quantify these cells. Labeling indices (LI) were measured before and after radiation. Unirradiated 10-mm tumors had a mean LI of 17.5%. After a single dose of 20 Gy there was depression of LI after 1 day followed by a rapid increase to greater than control values after 5 days. Analysis performed after five fractions showed that LI was dependent on the dose per fraction and interval between fractions. After 5 and 7 Gy/fraction LI remained similar to control values during daily fractionation but was significantly depressed after twice daily fractionation. With doses greater than 10 Gy/fraction there was marked depression of LI using both fractionation schedules. These changes in LI correlated well with changes in tumor volume after radiation. Tumors were also biopsied after 5 fractions of a 20-fraction course to see if LI would predict for tumor control. LIs of greater than or equal to 10% were associated with lack of tumor control at 90 days while all controlled tumors had a significant depression of LI. Changes in LI after radiation were a reasonable indication of the amount of repopulation occurring and might be useful in selecting patients for altered fractionation schedules.