Antilymphocyte Monoclonal Antibodies Research Articles

Monoclonal antibody therapy in rheumatoid arthritis

Monoclonal antibodies bind to their targets with high specificity and therefore have excellent potential as therapeutic agents. Biotechnological advances have allowed the production of large quantities of engineered monoclonal antibodies for therapeutic use. Recent research in rheumatoid arthritis has identified important mediators of synovitis. Monoclonal antibodies targeting these have been tested in clinical trials over the last decade. Anti-cytokine therapies, in particular anti-tumour necrosis factor alpha monoclonal antibodies, suppressed inflammation and produced rapid symptomatic improvement. Anti-lymphocyte monoclonal antibodies produced long-lasting disease suppression in animal models of rheumatoid arthritis. The use of depleting anti-lymphocyte monoclonal antibodies in rheumatoid arthritis had been disappointing as they did not penetrate the synovial joint in sufficient quantity to suppress disease without producing severe and protracted peripheral blood lymphopenia. Consequently, their use in rheumatoid arthritis had been abandoned. In contrast, clinical trials of non-depleting anti-CD4 monoclonal antibodies in rheumatoid arthritis showed that they could suppress synovitis. However, it remains unclear whether they could lead to prolonged disease improvement.

2. Scintigraphic evaluation of thyroid dysfunction following anti-lymphocyte monoclonal antibody treatment of multiple sclerosis

2. Scintigraphic evaluation of thyroid dysfunction following anti-lymphocyte monoclonal antibody treatment of multiple sclerosis

Anti-CD43 inhibition of T cell homing.

The homing of lymphocytes from the blood is controlled by specialized processes of lymphocyte-endothelial cell interaction. Interference with these processes offers the potential to manipulate lymphocyte traffic, and thus to modulate normal and pathologic immune and inflammatory responses. We selected antilymphocyte monoclonal antibodies (mAbs) for inhibition of lymphocyte binding in vitro to lymph node high endothelial venules (HEV), specialized vessels that support lymphocyte recruitment into lymph nodes. mAb L11 blocks T cell binding to lymph node and Peyer's patch HEV and inhibits T cell extravasation from the blood into organized secondary lymphoid tissues. In contrast, L11 has no effect on lymphocyte binding to purified vascular ligands for L-selectin, alpha4beta7, or LFA-1, suggesting that it inhibits by a novel mechanism. The L11 antigen is CD43, a sialomucin implicated in vitro in regulation of lymphocyte activation, whose expression is often dysregulated in the Wiskott-Aldrich syndrome. CD43 represents a novel target for experimental and therapeutic manipulation of lymphocyte traffic and may help regulate T cell distribution in vivo.

Recent clinical trials in the rheumatic diseases

This paper reviews clinical trials that have been published during the course of the past year on the rheumatologic diseases. The greatest number of clinical trials were done in rheumatoid arthritis. These trials show promising results for combination therapy with disease-modifying antirheumatic drugs, whereas results of studies with monoclonal antilymphocyte antibodies have been disappointing. The role of oral collagen remains to be defined. Nonsteroidal anti-inflammatory drugs with selective cyclooxygenase-2 (Cox-2) inhibition may have a more favorable toxicity profile and are likely to find wide use. As adjuvant therapy, trimethoprim-sulfamethoxazole appears to be useful in preventing relapses in Wegener's granulomatosis, and patients develop fewer infections. With the exception of juvenile rheumatoid arthritis, intravenous immunoglobulin therapy appeared ineffective in the diseases studied. The inclusion of more standardized and disease-specific outcome measures has enhanced the quality of clinical trials in rheumatology and their applicability to rheumatologic practice.

Variables predictoras de mortalidad precoz tras el trasplante cardíaco ortotópico en adultos

The purpose of the study was to analyze some variables of donors, recipients and surgical procedures in order to discover factors that could predict mortality during the early stage (< 30 days) of orthotopic heart transplants. 125 consecutive orthotopic heart transplants in adults were analyzed. The average age was 51 +/- 11 (range: 12-67), 109 (87%) were men, 16 were women (13%). Two groups were compared: 15 patients who died within 30 days after heart transplant and 110 who survived during that period. Immunosuppressive protocol: preoperative: Cyclosporin + Azathioprine. Intraoperative: Methylprednisolone Postoperative: Methylprednisolone (first 24 h), antilymphocyte monoclonal antibodies (7-10 days after heart transplant) + Cyclosporin + Azathioprine + Corticoids. The following parameters of the recipient were analyzed: sex, age, weight, size, thoracic perimeter, pretransplant cardiopathy, previous thoracic operations, functional stage or need for catecholamines during the days prior to the transplant, pulmonary artery pressure and resistance, history of systemic arterial hypertension, elevation of creatinine, blood type, urgent transplant indication, receptor/donor weight relationship. The following parameters of donors and operation were analyzed: sex, age, weight, thoracic perimeter, period in intensive care unit, dose of dopamine and dobutamine, blood type, origin of the organ, cause of death, ischaemia time, cardiopulmonary by-pass time and cardioplegia type. The rate of early mortality was 12%. The univariate analysis showed differences in: prior cardiovascular surgery, receptor blood type, need for urgent transplantation, pulmonary artery resistance > 2.5 Wood Units, cardiopulmonary by-pass time, weight relationship between receptor and donor. The death cause of the donor proved significant. On multivariate analysis, the following parameters independently predicted early mortality: history of operation with extracorporeal circulation, high pulmonary artery resistance, urgent transplant, receptor/donor weight relation and time of extracorporeal circulation. We believe that the results of our experience can help to stratify the risk in the orthotopic heart transplant recipient and even to contraindicate the procedure in some cases showing an accumulation of poor prognostic factors in borderline recipients.

Treatment of refractory Wegener's granulomatosis with humanized monoclonal antibodies

Conventional immunosuppression for systemic vasculitides is limited by substantial side-effects, cumulative drug toxicity and refractoriness in some patients. Six Wegener's granulomatosis patients who had been refractory to conventional therapy for at least 6 months, were treated with humanized monoclonal antibodies specific to lymphocyte CD52 or CD4 antigens. Diagnosis was on clinicopathological grounds, supported by the presence of autoantibodies to Proteinase 3. Histological evidence of persistent disease activity was obtained for each patient. Humanized monoclonal anti-CD52, with or without anti-CD4, was given intravenously up to 40 mg/day for up to 10 days. Remission, (programmed withdrawal of drug therapy without return of refractory disease) was achieved in all patients. Cytotoxic drugs were discontinued at the time of monoclonal antibody treatment and not used again; steroids were withdrawn gradually. Four patients relapsed at 1.5, 5, 10 and 18 months, and were treated successfully with further monoclonal antibody therapy alone. Three years after the study began, five patients are well; one patient died at surgery whilst in remission. Humanized monoclonal antilymphocyte antibodies may provide an effective treatment in patients with systemic vasculitis which is refractory to steroids or cytotoxic agents, or who are intolerant of these drugs.

Immunomodulation by levamisole in patients with recurrent aphthous ulcers or oral lichen planus

The purpose of this study was to evaluate the effect of levamisole on the immune system of patients with recurrent aphthous ulcers (RAU) or oral lichen planus (OLP) in an open trial. Lymphocyte subsets, serum immunoglobulins, and circulating immune complexes (CIC) in patients with RAU or OLP and in normal control subjects were determined by an indirect immunofluorescence (IIF) technique with monoclonal anti-lymphocyte antibodies, by single radial immunodiffusion, and by precipitation with 3% polyethylene glycol, respectively. In addition, the anti-nuclear antibodies (ANA) and anti-basal cell antibodies (anti-BCA) in sera were detected by an IIF technique. We found a significant improvement in clinical symptoms and normalization of the decreased CD4/CD8 ratio in RAU patients after levamisole treatment. Moreover, the decreased CD4/CD8 ratio, which persisted until the remission stage in the untreated RAU patients, reverted to normal in the active late stage in the levamisole-treated patients. This reversion of aberrant cellular immunity in an earlier stage of the ulcer cycle may explain why RAU patients experience symptom improvement after levamisole treatment. Although RAU patients treated with levamisole for 1 to 3 or 4 months still had higher than normal levels of CIC and serum immunoglobulins, the levels of their IgA and IgM returned to normal values after 4 months of levamisole treatment. The serum ANA detected in 6 patients with RAU and 3 patients with erosive OLP disappeared after 1-22 months of levamisole treatment. The disappearance of serum anti-BCA was also observed in 50% of the anti-BCA-positive patients with erosive OLP after 3-13 months of levamisole treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

OKT3: Immunology, production, purification, and pharmacokinetics

OKT3 is a monoclonal antilymphocyte antibody produced by a murine hybridoma technique. It differs from polyclonal antilymphocyte antibody preparations in that it is specific for one epitope of the T lymphocyte and is a pure product with batch‐to‐batch standardization. OKT3 binds to the CD3/T‐cell receptor complex, which is located on the surface of mature T lymphocytes and is involved in antigen recognition and cell activation. It appears to produce its potent immunosuppressant effect by: 1) opsonization of circulating T cells; 2) modulation of the CD3/T‐cell receptor complex on T cells; and possibly 3) T‐cell apoptosis. OKT3 also activates T cells and produces the cytokine release syndrome observed with first‐time administration of the drug. OKT3 has a half‐life of approximately 18 h, far shorter than that of human immunoglobulin.

CAMPATH‐1 monoclonal antibody therapy in severe refractory autoimmune thrombocytopenic purpura

Six patients with autoimmune thrombocytopenic purpura (three of whom had CLL/NHL and one previous Hodgkin's disease) refractory to conventional therapy were treated with an antilymphocyte monoclonal antibody directed at CDw52 (CAMPATH-1). We observed response in four of the five evaluable patients; in three patients the response has lasted more than 4-9 months. However, response did not occur in most cases until 4-6 weeks after the commencement of the antibody therapy, suggesting that the mechanism of action is probably that of immune modulation.

Rapid development of an immunoblastic lymphoma and death in children following cadaveric renal transplantation

We report on three children who underwent cadaveric renal transplantation and subsequently developed an immunoblastic lymphoma, leading to death in two patients. The development of the lymphoma occurred following a multidrug immunosuppression regimen ending with monoclonal antilymphocyte (OKT 3) treatment for biopsy-proven cellular and vascular acute rejection. These patients represent three of 11 children who received OKT 3 treatment for rejection in the last 18 months at this institution. Following the diagnosis of lymphoma, all three patients were treated by transplant nephrectomy, cessation of immunosuppression, and administration of intravenous acyclovir. The first two patients died at 4 days and 4 weeks, respectively, after the definitive diagnosis was made with widespread metastatic disease. The remaining child is a short-term survivor (13 months), free of demonstrable malignancy. Multidrug regimens for immunosuppression have a profound effects on T cell function. These effects, when combined with a primary infection by the Epstein-Barr virus, are implicated in the rapid development of the lymphomas and are responsible for the death of these two children.

Graft versus Host Disease in Extremely Low Birth Weight Neonate

To the Editor.— Graft vs host disease (GVHD) in extremely low birth weight neonates following multiple blood transfusions is probably more frequent than is generally thought.1 Recently, such a case was described by Funkhouser et al.2 We wish to report our experience with an extremely low birth weight neonate with GVHD, presumably induced by blood transfusions. Immunotherapy with rat antilymphocyte monoclonal antibody(Campath 1G) failed to induce any clinical change. The patient was a boy,

Characterization, specificity, and IgV gene usage of anti-lymphocyte monoclonal antibodies from perinatal mice.

Previous studies have shown that CD5+ B cells predominate during development of the immune system and frequently secrete self-reactive antibodies, some of which appear to influence the development of the adult B cell repertoire. In addition, we now show that a high frequency of perinatally derived antibodies react with lymphocytes. Hybridomas derived from perinatal liver and splenic B cells and from spleens of adult BALB/c and C57BL/6 mice were screened by immunofluorescence on thymocytes. Anti-lymphocyte antibodies, all of the IgM isotype, were detected at a high frequency from perinatal fusions, but none were obtained from adult mice. These anti-lymphocyte mAbs were heterogeneous because they stained different subsets of peripheral T and B lymphocytes. Although the antigens recognized by these mAbs were heterogeneous with respect to their sensitivity to a variety of enzymes, 13 of the 19 mAbs recognized epitopes which were modulated by phosphatidylinositol-phospholipase C treatment. Inhibition experiments suggested that six of these 13 mAbs shared the same molecular specificity, and that they recognized the same T cell subset (62% of CD4+ and 98% of CD8+ cells). Furthermore, three of these mAbs immunoprecipitated the same 100 kDa protein from thymocytes (70 kDa in reducing conditions). The related molecular specificity of some anti-lymphocyte mAbs was also reflected by their restricted V gene usage. Three of the five mAbs specific for the 100 kDa protein used very similar or identical germline SM7 VH genes. In addition to using the same germline D and JH genes, they also exhibited identical VH-D-JH joins, despite originating from distinct fusions. Analysis of light chains also showed some restriction by preferential use of germline V kappa 4 and J kappa 5 genes. Together, these results suggest that the restricted antibody repertoire characteristic of mouse fetal and neonatal B cells is also reflected in the production of anti-lymphocyte antibodies. These B cells appear consistently in early development, use germline V genes, and express a characteristic VH-D-JH join.

Identification and quantification of human peripheral blood lymphocytes and monocytes following migration into nitrocellulose filters

Previously, in order to evaluate the migration of specific types of lymphocytes (e.g., T or B cells, CD4 or CD8 subsets) using the Boyden chamber technique, the relevant cell populations have first been purified. We report here a method which permits identification of the lymphocytes following migration into the nitrocellulose filters. After fixation, the filters are exposed to specific anti-lymphocyte monoclonal antibodies and the reaction is visualized via a second gold-linked antibody. Monocyte-depleted lymphocytes isolated from human peripheral blood are routinely used for migration but mixed mononuclear cell preparations can also be used. This was shown by comparing lymphocyte migration in monocyte-containing and monocyte-depleted cell suspensions isolated from the same donor. The presence of monocytes did not influence the migration of normal resting T lymphocytes. With human peripheral blood as starting material the method is most suitable for the evaluation of T cell migration since, in most instances, T cells are the predominant lymphocyte population. When the B cell count is normal (5–10% total lymphocytes), quantification of B cell migration requires enrichment but not complete purification of this population. Migrating monocytes can also be identified. However, the antibody staining is less intense on the spread monocytes and, therefore, quantification must be performed by eye rather than with the Optomax image analyser.

Cerebellar injury due to phenytoin. Identification and evolution of Purkinje cell axonal swellings in deep cerebellar nuclei of mice.

The present study describes the identification and the ultrastructural and numerical evolution of Purkinje cell axonal swellings induced by phenytoin. Thirty male C57Bl/6J mice received phenytoin orally in doses up to 100 mg/kg daily and were killed after 3, 6, 10, 14, and 48 days of treatment. Light and electron microscopic investigations as well as morphometric analysis of cut surface area and numerical density of axonal swellings were performed. The swellings appeared as early as 6 days after initiation of treatment and gradually increased in size and frequency. Use of an anti-lymphocyte monoclonal antibody (CD 3), specifically cross-reacting with Purkinje cells, identified the swellings as dystrophic Purkinje cell axons. On grounds of their ultrastructural appearance they were classified into three distinct types occurring at different time intervals after phenytoin exposure. At 6 days, most axonal swellings contained loosely aggregated membranous vesicles and tubules in a finely granulated matrix (type 1). At 14 days, larger axonal swellings appeared characterized by the presence of three-dimensional networks of branched and anastomosing membranous tubules (type 2). At 48 days, even larger axons contained bodies of highly condensed membranous material of sometimes paracrystalline appearance (type 3). It is suggested that phenytoin-induced axonal pathology of Purkinje cells is a dynamic process characterized by the progressive accumulation of proliferating membranous material arranged in an increasingly complex fashion.

Characterization of a Mitogenic Antilymphocyte Monoclonal Antibody of the IgM Isotype Obtained by Immunization with Leukoagglutinin‐Reactive Human T‐Lymphocyte Surface Componentsa

Characterization of a Mitogenic Antilymphocyte Monoclonal Antibody of the IgM Isotype Obtained by Immunization with Leukoagglutinin‐Reactive Human T‐Lymphocyte Surface Componentsa

Monoclonal Antibodies against Leucoagglutinin‐Reactive Human T‐Lymphocyte Surface Components

The binding specificities of three biologically active anti-lymphocyte monoclonal antibodies (MoAb) (K46M, K3G, and 3-19-2) produced against human T-cell surface components reactive with the mitogenic lectin leucoagglutinin from Phaseolus vulgaris (La) were analysed. K46M is a strong T-cell mitogen, while K3G and 3-19-2 inhibited cell-mediated cytotoxicity. Resting peripheral blood lymphocytes (PBL) contained 4-16% K46M+ cells, 8-35% K3G+ cells, and less than 0.3-4% 3-19-2+ cells. After stimulation with T-cell mitogens the proportion of K46M+ and 3-19-2+ cells increased markedly (mean 59 and 30% positive cells, respectively), while the increase in K3G+ cells was less prominent (38%). K46M-reactive structures were expressed on mature T cells and probably also on B cells. K3G reacted with B and T cells while 3-19-2 showed a broader specificity reacting also with erythrocytes. All three MoAb reacted with lipid extracts of resting and activated PBL as well as with purified neutral glycolipids of lymphoid origin. In addition 3-19-2 reacted with lipid extracts of erythrocytes. K46M immuno-precipitated four surface peptides from lectin-stimulated PBL. Their apparent molecular weights were 53,000, 42,000, and 16,000 (doublet). The 53,000 and 42,000 MW peptides were identified as the alpha and beta chains of the T-cell antigen receptor. The identity of the 16,000 MW peptides is presently unknown. K3G and 3-19-2 did not specifically precipitate any lymphocyte surface peptide.

Targeting of lymphocytes with 111In-labelled monoclonal antibodies.

In this paper, we emphasize the rationale and work-up studies for using two radiolabelled anti-lymphocyte monoclonal antibodies for in vivo application as radiolabelling agents for T and B cells. In vitro experimental work involved radioimmunoassays on human lymphoid cell lines and anticoagulated whole blood with identification of relevant binding kinetics in terms of antibody internalization and elution. We tested also for the effect of the radiolabelled monoclonal antibodies on in vitro cell function defined as mitogen-induced proliferation in whole blood. As a final work-up in an animal model, the distribution of both unlabelled and 111In-labelled anti-Pan T cell monoclonal antibody was studied in the rat. Results from the in vitro experiments pointed to the possibility of using the described technique for specific lymphocyte radiolabelling. The in vivo application enabled us to identify optimal doses of antibody and radioactivity which showed agreement with the in vitro data.

Selective manipulation of the immune response in vivo by monoclonal antibodies.

The development of monoclonal antilymphocyte antibodies has greatly enhanced our ability to identify and bind specific antigens selectively on functionally distinct cells of the immune system. As a result, monoclonal antibodies have become a valuable tool in studies of the cellular mechanisms underlying immune responses. Moreover, because they can selectively alter immune responses in vivo, monoclonal antilymphocyte antibodies hold considerable promise as potential therapeutic agents for immunologically mediated disorders such as allograft rejection, graft-vs-host disease, and many autoimmune diseases. This review addresses the prospects for using monoclonal antilymphocyte antibodies in vivo and discusses some of the problems that remain to be solved.

Nosocomial and other difficult infections in the immunocompromised cardiac transplant patient

Infections continue to be a major cause of morbidity and mortality in cardiac transplant patients (Stinson et al,, 1971; Griffith et al., 1982). In the past 10 years, major advances have been made in the immunosuppressive therapy of organ rejection with the development of such drugs as cyclosporin and specific antilymphocyte monoclonal antibodies. In spite of these advances, infectious complications remain a potentially life-threatening problem for cardiac transplant recipients. Since 1982, we have performed 192 cardiac transplants at Texas Heart Institute and St. Luke’s Episcopal Hospital in Houston, Texas. With this experience, we have been able to define a distinctive pattern to the infectious complications seen in cardiac transplant patients. During the first month following transplantation, common nosocomial infections, such as pneumonia, wound infection or bacteraemia, occur almost exclusively as the serious infectious complications. After the first post-transplant month, nosocomial infections become much less frequent and opportunistic infections replace them as the major infection problem. Fortunately, cardiac transplant patients who survive for more than 1 year can expect infrequent infectious complications of either type.

Monoclonal antilymphocyte antibody (OKT3) treatment of acute renal allograft rejection.

Recent advances in immunosuppressive therapy have dramatically improved the survival rates for recipients of organ allografts by reducing the frequency of rejection. Cyclosporine, azathioprine, and prednisone for immunoprophylaxis are especially effective. When rejection occurs, the treatment usually includes high doses of oral or intravenous corticosteroids, antilymphocyte globulin, or antithymocyte globulin. A new monoclonal antilymphocyte antibody, OKT3, promises to improve allograft survival rates further.