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J Ritz

Publications and source records attributed to J Ritz.

At least 145 records · Page 8Linked to original sources
PubMed1990

Fc gamma receptor type III (CD16) is included in the zeta NK receptor complex expressed by human natural killer cells.

We recently reported that CD3- natural killer (NK) cells express the zeta chain of the T-cell receptor complex (zeta NK) in association with higher molecular weight structures whose expression differs between individual NK cell clones. Because NK cell cytolytic activity is known to be triggered by perturbation of the type III Fc gamma receptor (CD16), we sought to determine whether this activating molecule is included in the zeta NK molecular complex. Biochemical evidence for a physical association between CD16 and zeta NK was obtained by comparing immunoprecipitates formed using monoclonal antibodies reactive with each of these molecules by SDS/polyacrylamide gel electrophoresis, immunoblotting, and peptide mapping. In both clonal and polyclonal populations of CD3- NK cells, CD16 and zeta NK specifically associated with one another. Functional evidence for a specific association between CD16 and zeta NK in intact cells was obtained by demonstrating a coordinate down-modulation of both of these molecules induced by either phorbol 12-myristate 13-acetate or monoclonal antibodies reactive with CD16. Our results suggest that Fc gamma receptor type III (CD16) is included in the zeta NK complex and that this complex is likely to play an important role in NK cell activation.

Antibodies, Monoclonal↗
PubMed1990

Autoimmune pancytopenia following allogeneic bone marrow transplantation.

A 47-year-old female developed autoimmune hemolytic anemia, autoimmune neutropenia, and autoimmune thrombocytopenia 19 months following allogeneic bone marrow transplantation for chronic myelogenous leukemia. Treatment with high-dose corticosteroids resulted in marked improvement in all three cell lines.

Autoimmune Diseases↗
PubMed1990

The evolving role of bone marrow transplantation in the treatment of chronic myelogenous leukemia.

Bone marrow transplantation is the only treatment that can result in long-term disease-free survival and possible cure in a significant number of patients with CML. Several prognostic features influence relapse and survival following allogeneic BMT for CML. The most important factor is treatment of patients during chronic phase. The timing of BMT in chronic phase CML remains controversial, because the Seattle findings that BMT done within a shorter interval from diagnosis to transplant was associated with improved survival has not been confirmed by the IBMTR. No factor can predict in the individual patient the timing of transformation, even in patients with low-risk chronic phase CML, but we believe that allogeneic BMT should be offered as soon as possible for newly diagnosed patients who have histocompatible siblings. More widespread application of BMT in CML is possible because of effective methods for preventing GVHD, the major cause of morbidity after allogeneic BMT. However, in vitro techniques for the depletion of donor marrow T cells have resulted in higher graft failure and relapse rates. More precise understanding of the immune mechanisms involved may permit more selective depletion techniques which not only abrogate GVHD but also permit sustained engraftment and preserve GVL effect. This may extend application of BMT for patients with mismatched related or histocompatible unrelated donors. It is of interest that cytogenetic relapse after BMT is not invariably followed by hematologic relapse. It is likely that the use of polymerase chain reaction techniques which detect the bcr-abl rearrangement at a very low level will identify the persistence of the malignant clone after allogeneic BMT in even more patients. At present, the significance of such findings is unclear, but further study of the kinetics of disappearance of the CML clone post-BMT may increase our understanding of the immune mechanisms involved in suppression of the malignant clone and determine whether in fact CML can be cured using BMT approaches.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

Acute and chronic pulmonary complications following autologous bone marrow transplantation in non-Hodgkin's lymphoma.

Whereas intensive chemoradiotherapy with bone marrow salvage may be the only chance for cure in a number of patients with non-Hodgkin's lymphoma, high complication rates with subsequent mortality have been detrimental to our ability to cure many patients. Prominent among these complications is pulmonary toxicity, in the form of acute and infectious complications and interstitial pneumonitis. We report here our experience with 100 patients receiving autologous bone marrow transplants for non-Hodgkin's lymphoma. The incidence of interstitial pneumonitis (IP) was 7.6% and our mortality from IP was 1%, the lowest reported.

Acute Disease↗
PubMed1989

Anti-B-cell monoclonal antibody-purged autologous bone marrow transplantation for B-cell non-Hodgkin's lymphoma: phenotypic reconstitution and B-cell function.

In the present report we have attempted to examine immunologic reconstitution following high-dose chemoradiotherapy and anti-B-cell monoclonal antibody (MoAb)-purged autologous bone marrow transplantation (ABMT). By cell-surface phenotypic analysis, the majority of patients had normal percentage of natural killer cells (NK), monocytes, and CD8+ T cells at one month post-ABMT. In contrast, the percentage of CD4+ T cells was reduced for at least 3 years, and the CD4:CD8 ratio reflected this imbalance. B-cell reconstitution was slightly prolonged, with normal percentage and absolute numbers of CD20+ B cells evident by 3 months. Although B cells returned by 3 months, in vitro assessment of B-cell function demonstrated impairment of proliferative responses to either anti-immunoglobulins bound to beads (anti-Ig), Epstein-Barr virus (EBV), or interleukin-2 (IL-2) for approximately 1 year and low molecular B-cell growth factor (BCGF) for approximately 2 or more years. Moreover, in vivo B-cell reconstitution demonstrated a more selective defect, with normal levels of immunoglobulin IgM returning at 6 months, IgG at 12 months, and IgA after 2 years. Despite normal numbers of B cells and relative normal levels of Ig early following ABMT, our in vitro data suggest an intrinsic defect in B-cell responsiveness. Moreover, these defects are similar to those observed following nonpurged autologous and allogeneic BMT, although the interval of immune impairment appears more prolonged.

Antibodies, Monoclonal↗
PubMed1989

Expression of Epstein-Barr virus transformation-associated genes in tissues of patients with EBV lymphoproliferative disease.

Epstein-Barr virus (EBV) has been associated with serious or fatal lymphoproliferative disease in immunocompromised patients. EBV nuclear protein 2 and latent membrane protein are characteristically expressed in B lymphocytes proliferating in vitro in response to growth transformation by EBV. These two proteins are thought to be effectors of lymphocyte growth since they increase the expression of B-lymphocyte activation (CD23) and cell-adhesion (LFA 3 and ICAM 1) molecules in vitro. Using monoclonal antibody-immune microscopy, we have demonstrated that these two EBV proteins and their associated B-lymphocyte activation or adhesion molecules are expressed in the infiltrating B lymphocytes in immunocompromised patients with EBV lymphoproliferative disease. These monoclonal antibodies should be useful in the early diagnosis of EBV lymphoproliferative disease and in distinguishing it from other B-lymphocyte cancers associated with EBV, such as Burkitt's lymphoma. The finding of EBV nuclear protein 2 and latent membrane protein and their associated activation or adhesion molecules provides a further pathophysiologic link between EBV and the proliferation of B lymphocytes in immunocompromised patients.

Adult↗
PubMed1989

CD3-negative natural killer cells express zeta TCR as part of a novel molecular complex.

Natural killer (NK) cells are large granular lymphocytes capable of killing tumour cells in a non-MHC restricted manner. NK cells do not express cell-surface CD3, or any known target recognition structure analogous to the T cell antigen receptor (TCR) heterodimers (alpha beta or gamma delta). Consistent with their lack of expression of a CD3-TCR complex, NK cells do not require prior sensitization or antigen presentation by accessory cells to specifically recognize their tumour targets. Although NK cells do not express CD3-TCR, they do express CD2, the target of an alternative activation pathway which is functional in both T cells and NK cells. In T cells, this alternative activation pathway utilizes some component of the CD3-TCR complex as a transducer molecule that is required for mitogenesis. The fact that NK cells are activated by this alternative pathway suggested that they might express a related subunit of the CD3-TCR complex capable of transducing the CD2-mediated signal. Here we show that human NK cells express the zeta-chain of the TCR complex in association with additional structures not included in CD3-TCR.

Antibodies, Monoclonal↗
PubMed1989

Activation of human cytolytic cells through CD2/T11. Comparison of the requirements for the induction and direction of lysis of tumor targets by T cells and NK cells.

We studied the mechanisms whereby human T cells and NK cells are activated and directed to lyse tumor targets through the CD2 (T11/E-rosette) Ag. Using two cloned NK lines, we showed that these cells, as had previously been shown for T cells, could be directed to lyse an "NK-resistant" tumor target in the presence of antibody heterodimers. These heterodimers consisted of a (mAb) to CD2 (anti-T11(2) or anti-T11(3] linked to a mAb recognizing the tumor cell (J5, anti-CALLA). However, distinct differences between NK cells and T cells were observed with regard to the requirements for such directed lysis: first, only one epitope of CD2 on NK cells (either T11(2) or T11(3] needed to be recognized by the antibody heterodimer in order for directed lysis to occur, whereas for T cells both T11(2) and T11(3) epitopes had to be recognized. Second, in confirmation of previous data with monomeric anti-T11(2) or anti-T11(3) antibody, heterodimers constructed with these reagents enhanced conjugate formation between NK cells and tumor targets, whereas no such enhancement was seen with T cells. All types of heterodimer directed lysis were dependent on the adhesion molecule LFA-1, as an anti-LFA-1 antibody-blocked lysis. Third, whereas in T cells lysis mediated through CD2 appeared to be regulated by CD3 but not vice versa, all types of lysis by NK cells appeared to be regulated through CD2. Finally we showed that F(ab')2 fragments of the anti-T11(2) and anti-T11(3) antibodies could activate NK cells, but were unable to activate T cells either as cloned cytolytic lines, or in populations of PBL. The implications of our findings with regard to the role of CD2 in the activation of cytolytic cells is discussed.

Antibodies, Monoclonal↗
PubMed1989

Identification of carboxypeptidase and tryptic esterase activities that are complexed to proteoglycans in the secretory granules of human cloned natural killer cells.

Human cloned 35S-labeled NK cells were disrupted by nitrogen cavitation, and their secretory granules were obtained by filtration through 5-micron and 3-micron membrane filters followed by Percoll density-gradient centrifugation. These granule preparations, which contained 35S-labeled chondroitin sulfate A proteoglycans, were sonicated and were analyzed for carboxypeptidase activity and tryptic serine esterase activity. A carboxypeptidase activity that digested angiotensin I to des-Leu-angiotensin I, Ile-His-Pro-Phe to Ile-His-Pro and Phe, and hippuryl-L-phenylalanine to hippuric acid and Phe was detected in the granules of these NK cells. As determined by cleavage of the tetrapeptide, the pH optimum of the carboxypeptidase was 7.0. As assessed by the cleavage of N-benzyloxycarbonyl-L-lysine thiobenzyl ester (BLTe), the granule preparations also contained a serine esterase with trypsin-like specificity that had a pH optimum of 8.5. When the isolated secretory granules were disrupted and chromatographed on columns of Sepharose CL-2B in PBS, greater than 60% of the BLTe serine esterase activity and essentially all of the carboxypeptidase activity filtered as a macromolecular complex with approximately 8% of the 35S-labeled proteoglycans. Whereas treatment with 4 M urea or nonionic detergent failed to disrupt the macromolecular complex, the serine esterase activity was dissociated from the macromolecular complex in the presence of 3 M NaCl, demonstrating an ionic interaction with the proteoglycans. No difference was observed in the disaccharide composition of the chondroitin sulfate glycosaminoglycans of the 35S-labeled proteoglycans that were complexed with the enzymes as compared to those that were not complexed. These studies indicate that the secretory granules of human NK cells contain serine esterase activity and carboxypeptidase activity, both of which have neutral pH optima, and both of which are bound to protease-resistant chondroitin sulfate proteoglycans.

Carboxypeptidases↗
PubMed1989

Clonal evidence for the induction of NKH1 on activated human thymocytes. Functional changes associated with antigen expression.

Freshly isolated human thymocytes lack the NKH1 antigen and the ability to lyse target cells without major histocompatibility complex restriction. Short-term culture of human thymocytes in interleukin (IL) 2 results in the generation of non-major histocompatibility complex-restricted effector cells, all of which express NKH1. The mechanism by which these cells appear in culture has yet to be elucidated. In the present studies, we developed thymocyte clones and performed a molecular analysis of T cell receptor gene rearrangements to demonstrate that the expression of NKH1 antigen is induced on the surface of NKH1- thymocytes in the presence of IL2. In addition, we were able to show that the NKH1+ fraction consistently displayed an increased proliferative response to similar concentrations of IL2 when compared to NKH1- cells, for both clonal and polyclonal populations of thymocytes. Taken together, these studies demonstrate that the initial appearance of the NKH1 antigen following thymocyte culture in the presence of IL2 results from the induction of NKH1 expression on NKH1- thymocytes, while the subsequent predominance of this cell type also results from an enhanced proliferative response to IL2 which coincides with NKH1 expression.

Antigens, CD↗
PubMed1989

Autologous bone marrow transplantation therapy for multiple myeloma.

We have begun an autologous bone marrow transplantation (ABMT) treatment protocol for patients with myeloma who achieve a minimal disease (less than 10% marrow plasma cells) status. Sites of bony disease are irradiated before BMT. Melphalan 70 mg/m2 on days 1 and 2 is followed by 1200 rads total-body irradiation administered in fractionated doses over 3 d. Autologous marrow which has been previously treated with anti-CALLA, B1, and PCA-1 monoclonal antibodies is then thawed and reinfused. 4 males and 2 females with median age of 46 yr (41-56) have been treated. Granulocytes greater than 500/mm3 and platelets greater than 20,000/mm3 were noted at 21 (12-46) and 23 (12-53) d post-transplant (PT), respectively. Acute mucositis and dermatomal Herpes zoster developed in 3 patients each; all patients are clinically well at 233 (30-807) d PT. All patients achieved pathologically normal marrows, but monoclonal plasma cells and marrow myelofibrosis were each noted in a single patient at 486 and 272 d PT, respectively. A single patient has responded to alpha 2 interferon therapy PT; all others have received no therapy. AMBT offers an exciting new treatment for myeloma; however, relapses post-ABMT suggest that improved ablative regimens and/or marrow purging methods may be required.

Adult↗
PubMed1989

Mechanism of graft failure in HLA-matched and HLA-mismatched bone marrow transplant recipients.

This report characterizes the mechanism of graft failure in five patients who received allogeneic marrow depleted of T cells in vitro using anti-T12 (CD6) monoclonal antibody and rabbit complement. This group of five patients represents all patients who experienced early graft failure in a larger group of 59 consecutive patients given T12 depleted marrow over a 5-year period. Although all patients received ablative pre-transplant conditioning including total body irradiation (12-14 Gy) graft failure was more frequent in patients without genetically HLA-identical donors (four of 11 patients) than in patients with HLA identical sibling donors (one of 48 patients). In patients without genotypically identical donors, graft failure was observed with variable degrees of genetic disparity including two patients with HLA haplotype-mismatched sibling donors, one patient with a phenotypically HLA-matched parental donor, and one patient with an HLA-matched unrelated donor. In patients with both HLA identical and non-identical donors, results of immunophenotypic analysis demonstrated that early graft failure was associated with peripheral lymphocytosis with T cells expressing CD2, CD3, CD5, CD6, CD8 and Ia antigens. Direct cytotoxicity studies demonstrated specific lysis of donor cells by circulating lymphocytes and further analysis indicated that effector cells were derived from the recipients and not donors. Taken together, these results suggest that these allogeneic grafts did not 'fail', but rather that residual host cytotoxic T cells were responsible for active rejection of donor marrow.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Anti-CD4 and anti-CD2 monoclonal antibody infusions in subjects with multiple sclerosis. Immunosuppressive effects and human anti-mouse responses.

The immunologic responses to anti-T4 and anti-T11 mAb infusions were assessed in subjects with chronic progressive multiple sclerosis as part of phase I clinical studies. Eight subjects received five daily infusions (0.2 mg/kg/day) of either anti-T11 (CD2) or anti-T4 (CD4) murine mAb. It was found that in vivo anti-T cell mAb infusions specifically suppress in vitro measurements of the human immune response; anti-T11 mAb blocked T cell activation via the CD2 SRBC-binding protein, and anti-T4 mAb infusions abolished PWM-induced Ig synthesis without lysis of the CD4+ T cell subpopulations. With repeated infusions of the anti-T11 mAb in three subjects, anti-mouse antibodies were found in the circulation. Although the majority of human anti-mouse antibody was not isotype specific, significant anti-idiotypic-like activity was observed after repeated infusions in two of three subjects. The human anti-mouse antibodies were almost exclusively of the IgG isotype. The magnitude of the human anti-mouse response was significantly less after administration of either anti-T11 or anti-T4 as compared with anti-T12 mAb. Murine anti-T cell mAb can provide a specific, benign form of acute immunosuppression in humans. However, repeated administration of these reagents in more chronic diseases can result in anti-Id-like antibodies that block binding of the anti-T cell mAb to the T cell surface.

Animals↗
PubMed1988

Induction of natural killer effectors from human thymus with recombinant IL-2.

The NKH1 Ag is expressed on all cells in human peripheral blood capable of mediating spontaneous non-MHC restricted cytolytic function (i.e., natural killing). The majority of NK cells do not express CD3 Ag and do not express TCR gene products. However, approximately 20 to 25% of NKH1+ cells coexpress CD3 and TCR proteins. Both NKH1+CD3+ and NKH1+CD3- effectors can proliferate in response to IL-2 which also results in enhancement of cytolytic function. In the present studies, we examined thymocytes after incubation with rIL-2 for the presence of NKH1+ cells and for the development of non-MHC restricted cytolytic function. NKH1+ cells and NK activity could not be detected in fresh thymus. After culture with rIL-2 only, NK activity appeared in 3 days, reached a maximum after 7 days, and was effective against a panel of NK-sensitive targets. NK activity was correlated with the expression of NKH1 on the surface of in vitro proliferating thymocytes and immunofluorescent cell sorting demonstrated that almost all cytolytic activity was mediated by NKH1+ cells. As expected given the thymic origin of these cells, the majority of NKH1+ cells in culture expressed CD3. However, all cultures contained NKH1+CD3- effector cells which represent 15 to 40% of the NKH1+ population. As in peripheral blood, both NKH1+CD3- and NKH1+CD3+ exhibited non-MHC-restricted cytotoxicity, but only CD3+ effectors could be inhibited by anti-T3 mAb. These findings demonstrate that rIL-2 alone can induce subpopulations of thymocytes to proliferate, to express the NKH1 marker and become NK active in vitro. Furthermore, they suggest that the thymus which plays a role in the differentiation of NKH1+CD3+ NK effectors may also play a role in the differentiation or maturation of NKH1+CD3- NK effectors.

Antigens, Differentiation↗
PubMed1988

T11/CD2 activation of cloned human natural killer cells results in increased conjugate formation and exocytosis of cytolytic granules.

The T11 (CD2) antigen has been found to be an alternate pathway for antigen-independent activation of resting T cells. T11 triggering also results in activation of NK cells and enhancement of their cytolytic function. The present studies were carried out to further define the mechanisms whereby cytotoxicity is enhanced after T11 activation. A series of clonal human NK cell lines were analyzed after incubation with monoclonal anti-T112 and anti-T113 antibodies specific for different epitopes of the CD2 protein. Anti-T112/3 triggering resulted in increased cytotoxicity against a variety of target cells. Similar results were obtained with F(ab')2 fragments of anti-T112/3, indicating that this effect was not mediated through binding of FcR. The induction of cytotoxicity was found to be associated with increased formation of effector cell-target cell conjugates and with release of secretory granule-localized 35S-labeled proteoglycans. Both enhanced conjugate formation and cytotoxicity could be blocked by anti-lymphocyte function-associated antigen (LFA-1) mAb. Ultrastructural analysis of NK cells after T11 activation demonstrated increased adherence of effector cells to targets and other NK cells as well as a directional reorientation of cytoplasm and intracellular granules toward the area of contact between cells. Discharge of granules occurred into pockets bounded by closely apposed plasma membranes. In the presence of anti-LFA-1 and anti-T112/3, the close apposition and formation of pockets between effector cells and target cells did not occur but the cells exocytosed their intracellular granules. T11 activation of NK cloned cells also resulted in the formation of the homotypic conjugates and autocytotoxicity. As seen with resistant allogeneic targets, autocytotoxicity was mediated by F(ab')2 fragments of T112/3 antibodies and could be blocked by anti-LFA-1 antibody. Ultrastructural analysis of NK cloned cells after T11 activation confirmed the presence of homotypic conjugates with reorientation of effector cells toward one another and discharge of cytolytic granules into pockets formed between NK cloned cells. Taken together, these results indicate that T11-induced cytolytic function of NK cells is, in part, mediated through increased binding of effector cells and targets and that enhanced conjugate formation is at least in part mediated by the LFA-1 antigen. In addition, T11 activation results in the triggering of the cytolytic mechanism of NK cells and the exocytosis of cytolytic granules and their constituents.

Antibodies, Monoclonal↗
PubMed1988

Characterization of functional surface structures on human natural killer cells.

Recent studies on human NK cells have identified a number of surface antigens that can be utilized to define this population of cells and to identify functionally distinct subsets within this heterogeneous population. In addition, it has been possible to associate specific functional activities with several antigens expressed on NK cells as well as other hematopoietic cells. This information, which is summarized in Table III can be utilized to develop a framework for the classification of cytolytic effector cells. Of primary importance, this classification identifies subsets of cytolytic cells with distinct functional repertoires and distinct cytolytic mechanisms. The majority of NK cells in unstimulated peripheral blood and the majority of NK clones express NKH1 and CD2 antigens but do not express CD3 antigen. These cells morphologically appear as large granular lymphocytes and have broad cytolytic activity against a variety of allogeneic targets without primary sensitization. Consistent with the finding that these cells are CD3 negative, they have not been found to have rearrangement of genes encoding for TCR, or functional mRNA transcripts of either TCR alpha, TCR beta, or TCR gamma genes. In addition, these cells do not express heterodimeric surface proteins similar to those that have now been demonstrated to be MHC-restricted T cell receptors for antigen. Taken together, these findings provide strong evidence that NKH1+CD3- NK clones do not interact with target cells through a T cell receptor-like structure. Nevertheless, these NK cells do share several properties with conventional CTL. These functional T cell characteristics include (1) expression of CD2-T11/E rosette receptor antigen, and (2) utilization of LFA-1 surface antigen to enhance effector cell adhesion to target cells. As previously demonstrated for T cells, NK cells can be activated through the CD2 molecule and this has recently been shown to result in the enhancement of cytolytic function by these effectors. Since CD2 can also function as a cell surface ligand for LFA-3, an antigen expressed on NK targets, the CD2 molecule may be considered as a potential NK receptor structure. The fact that a very small subset of NK cells (approximately equal to 10%) as well as some NK clones (JT11) does not express CD2 argues against a potential role for CD2 as the NK cell receptor. Certainly, further studies will be necessary to clarify the role of CD2 on NK cells and to identify the mechanisms whereby NKH1+CD3- NK cells interact with targets in a non-MHC-restricted fashion.(ABSTRACT TRUNCATED AT 400 WORDS)

Antibodies, Monoclonal↗