Studies of a human T lymphocyte antigen recognized by a monoclonal antibody

A Review of Chimeric Antigen Receptor T-Cell Therapy for Myeloma and Lymphoma

Collectively, hematological malignancies account for the fourth most common malignancy. Myeloma and lymphoma are the most common types of hematological malignancies. Unfortunately, the management of refractory myeloma and lymphoma remains challenging. The discovery of new immunological therapies, namely chimeric antigen receptors T cells (CAR-T), outlined unprecedented B cell malignancies results. In this context, the CAR-T-based approach has led to the proliferation of many clinical studies. In this review, we will deal with the CAR-T structure, and we will summarize the primary clinical studies assessing the risks and benefits of CAR-T cell therapy. We will also deal with the adverse events and management of cytokine release syndromes/immune effector cell-associated neurotoxicity syndrome (ICANS). Subsequently, we will review potential future improvements to overcome refractoriness and improve expansion while decreasing CAR-T's off-target effects. The advances in the CAR-T platform represent a step forward with promising unlimited future possibilities that made it a paradigm-shifting for the management of B cell malignancies.

Hematopoietic Cell Transplantation and Adoptive Cell Therapy in Peripheral T Cell Lymphoma

PURPOSE OF REVIEW

Peripheral T cell lymphomas (PTCLs) are a heterogeneous group of diseases and represent approximately 10-15% of all non-Hodgkin lymphomas. Multiagent chemotherapy with a CHOP (cyclophosphamide, adriamycin, vincristine, prednisone)-like regimen is the current standard of care in the frontline setting, but outcomes for PTCL patients generally remain poor. Strategies used to improve survival and reduce the risk of relapse in PTCL patients include autologous hematopoietic cell transplant (autoHCT) and allogeneic HCT (alloHCT). Due to the relative rarity of these diseases, the evidence supporting the use of autoHCT and alloHCT is based on retrospective and single-arm prospective studies. Novel targeted therapies are now being incorporated into the treatment of PTCL, and they may play important roles in improving upon current standards of care. Herein, we summarize the evidence supporting HCT for the treatment of the most common PTCL histologic subtypes and highlight novel treatment strategies aimed at improving outcomes for these patients, including cutting-edge approaches using chimeric antigen receptor T cells (CAR-T).

RECENT FINDINGS

Given recent improvements in OS and PFS in CD30+ PTCL using the drug-antibody conjugate brentuximab vedotin (BV), new questions arise regarding the impact of BV on consolidative autoHCT, and its role as a maintenance therapy. Multiple histone deacetylase inhibitors (HDACis) have been approved for the treatment of relapsed/refractory PTCL, and these agents are being incorporated into HCT approaches, both in the frontline and maintenance settings. Early data incorporating these agents into novel conditioning regimens have been reported, and emerging evidence from recent trials suggests that CART cell therapies may prove effective in relapsed/refractory PTCL. The recommended treatment strategy in non-ALK+ PTCL remains induction with a CHOP-like regimen followed by consolidative autoHCT in first remission. In the relapsed/refractory setting, salvage chemotherapy followed by HCT (autoHCT or alloHCT depending on histologic subtype and HCT history) offers the only potential for cure or long-term remission. Ample room for improvement remains in the treatment of patients with PTCL, and novel treatment strategies incorporating targeted agents and CAR-T therapy may help to address the unmet needs of this patient population.

Targeting T cell malignancies using CAR-based immunotherapy: challenges and potential solutions

Chimeric antigen receptor (CAR) T cell therapy has been successful in treating B cell malignancies in clinical trials; however, fewer studies have evaluated CAR T cell therapy for the treatment of T cell malignancies. There are many challenges in translating this therapy for T cell disease, including fratricide, T cell aplasia, and product contamination. To the best of our knowledge, no tumor-specific antigen has been identified with universal expression on cancerous T cells, hindering CAR T cell therapy for these malignancies. Numerous approaches have been assessed to address each of these challenges, such as (i) disrupting target antigen expression on CAR-modified T cells, (ii) targeting antigens with limited expression on T cells, and (iii) using third party donor cells that are either non-alloreactive or have been genome edited at the T cell receptor α constant (TRAC) locus. In this review, we discuss CAR approaches that have been explored both in preclinical and clinical studies targeting T cell antigens, as well as examine other potential strategies that can be used to successfully translate this therapy for T cell disease.

Precocious aging of the immune system in Down syndrome: alteration of B lymphocytes, T-lymphocyte subsets, and cells with natural killer markers

Phenotype and proliferative ability of peripheral blood lymphocytes from 15 noninstitutionalized children affected with Down Syndrome (DS), in apparently good health, were studied and compared with those of 16 healthy control children of the same age. A complex derangement of all the major peripheral blood cell subsets, i.e., B cells, T cells, and natural killer (NK) cells, was present in DS children. A significant decrease of the absolute number of circulating lymphocytes, a marked and significant decrease of B lymphocyte absolute number and percentage, and dramatic modifications of the T-cell subsets were observed. The absolute number of CD4+ cells was significantly decreased, whereas CD8+ cells increased significantly in percentage but not in absolute number. A derangement of cells bearing markers associated with NK activity, such as CD57, CD16, and CD56, was observed. Among the most important alterations, the presence of a high number of CD57+, CD16- cells, of CD57+, CD8+ lymphocytes, and of CD3+, CD56+ lymphocytes was seen. Many of these alterations are similar to those characteristic of chromosomally normal subjects of advanced age. The hypothesis that the reduced thymic endocrine activity and the zinc deficiency characteristic of DS are responsible for the derangement of T and NK subsets is discussed.

Increased peripheral blood B-cells expressing the CD5 molecules in association to autoantibodies in patients with lupus erythematosus and evidence to selectively down-modulate them

The present investigation has been undertaken to analyze absolute and relative CD5+ B-cell numbers in patients with lupus erythematosus (LE), and concomitant B-CLL, and to monitor them under therapy. Peripheral blood lymphocytes of LE-patients, and healthy controls were analyzed by flow cytometry and direct immunofluorescence technique. Patients were treated with low-dose methotrexate (MTX). Before and during MTX treatment laboratory monitoring has been done. LE-patients had increased percentages of CD5+CD19+ as compared to controls (p < 0.0002), the absolute number of CD5+ B-cells was equal in controls and patients. Autoantibodies were positively correlated to the number of CD5+ B-cells in LE-patients. In a total of 140 LE-patients one male patient suffered from both LE and B-CLL (0.7%). He had increased absolute and relative CD5+ B-cells. MTX induced significant decrease of both total B-cell numbers, and CD5+ B-cells. The decrease of CD5+CD19+ cells was more pronounced than the decrease of total B-cells. Apoptosis rate increased in parallel to the drop-down of elevated CD5+CD19+ cells. Peripheral T-cell subsets remained stable under low-dose MTX. Both absolute and relative numbers of CD5+CD19+ cells should be taken into account in patients with LE. MTX seems to decrease B-cells, and preferentially to down-regulate B-cells expressing the CD5 molecule, which opens new therapeutic options and cell biological activities. The mechanism is unclear but apoptosis induction seems to be likely.

Origins and functions of B-1 cells with notes on the role of CD5

Whether B-1a (CD5+) cells are a distinct lineage derived from committed fetal/neonatal precursors or arise from follicular B-2 cells in response to BCR ligation and other, unknown signals remains controversial. Recent evidence indicates that B-1a cells can derive from adult precursors expressing an appropriate specificity when the (self-) antigen is present. Antibody specificity determines whether a B cell expressing immunoglobulin transgenes has a B-2, B-1a or marginal zone (MZ) phenotype. MZ cells share many phenotypic characteristics of B-1 cells and, like them, appear to develop in response to T independent type 2 antigens. Because fetal-derived B cell progenitors fail to express terminal deoxynucleotidyl transferase (TdT) and for other reasons, they are likely to express a repertoire that allows selection into the B-1a population. As it is selected by self-antigen, the B-1 repertoire tends to be autoreactive. This potentially dangerous repertoire is also useful, as B-1 cells are essential for resistance to several pathogens and they play an important role in mucosal immunity. The CD5 molecule can function as a negative regulator of BCR signaling that may help prevent inappropriate activation of autoreactive B-1a cells.

Comparison of Immunoperoxidase Staining of 3 Different Types of CD5 Antibodies in a Spectrum of Breast Lesions

Context.—We recently described a patient with chronic lymphocytic leukemia who presented with a breast carcinoma that stained positive for CD5 using a commercially available antibody (CD5-4C7, Novocastra, Newcastle upon Tyne, UK).

Objectives.—To study the distribution of CD5 immunoreactivity in tissue sections of a variety of benign and malignant breast lesions using the antibody CD5-4C7 and to compare the results with those obtained with 2 other commercially available CD5 antibodies (CD5/54/F6, Dako, Ely, Cambridgeshire, UK, and CD5/54/B4, Novocastra).

Design.—Paraffin sections of 102 breast biopsy specimens with various diagnoses were examined using the avidin-biotin immunoperoxidase complex technique.

Setting.—The histopathology department of a tertiary referral teaching hospital.

Results.—The staining results obtained with CD5-4C7 were different from those obtained with the other 2 antibodies. With 4C7, the normal and benign biopsy specimens showed varying numbers of positive epithelial cells and lymphocytes. Heterogeneous positive staining was also present in 47 (78%) of 60 invasive female breast carcinomas and in all 3 male breast carcinomas examined. A statistically significant correlation was found between CD5 positivity and tumor grade, with grade 3 tumors being less likely to be CD5 positive than grades 1 and 2 (P = .0035). No correlation was found between CD5 positivity and patient's age, tumor histologic type, axillary lymph node status, or progesterone receptors. On the other hand, the CD5/54/F6 and CD5/54/B4 antibodies only stained lymphocytes and occasional normal breast ducts, mostly those showing apocrine metaplasia. All other normal benign and malignant epithelial cells were negative.

Conclusions.—Positive staining for CD5 using the antibody 4C7 is seen in normal and benign breast tissue and 78% of invasive breast carcinomas. The positivity is more common in low-grade tumors. No significant staining was seen with the 2 other CD5 clones used in this study. The significance of the positive staining obtained with CD5-4C7 is not obvious, but this clone may be more sensitive than the others, or it may be recognizing an epitope shared by another antigen.

Quantitative flow cytometry for the differential diagnosis of leukemic B-cell chronic lymphoproliferative disorders

We have investigated whether the quantitative flow cytometry is an useful tool to better characterize B-cell chronic lymphoproliferative disorders (CLDs). Peripheral blood samples from 104 patients with leukemic B-cell disorders and 20 healthy donors were analyzed. Directly phycoerythrin-conjugated CD19, CD20, CD22, CD23, CD79b, and CD5 monoclonal antibodies (MoAbs) and QuantiBRITE pre-calibrated beads were used to calculate the number of antigen molecules per cell, expressed as antibody binding capacity (ABC). As compared to normal controls, in chronic lymphocytic leukemias (CLL) all MoAbs tested, with the exception of CD23 and CD5, showed lower ABC levels. In prolymphocytic leukemias (PL), CD5 and CD23 antigens were constantly absent while lower CD19 and CD22 ABC levels were observed. Hairy cell leukemias (HCL) displayed very high levels of CD20 and CD22. Of interest, splenic lymphomas with villous lymphocytes (SLVL) could be discriminated from HCL for higher CD79b and lower CD19 ABC values. Finally, higher CD20 levels were detected in follicular lymphomas (FL), whereas higher CD79b and CD5 levels characterized mantle cell lymphomas (MCL). Seven out of 61 CLL cases were defined as morphologically atypical. When compared with typical forms, lower levels of CD19 and CD23 and higher CD20 and CD22 ABC values were detected. However, we failed to demonstrate quantitative differences between atypical CLL and MCL. Our results suggest that quantitative flow cytometry may be a useful additional tool to better identify some types of B-cell CLDs.

Most Acute Myeloid Leukemia Progenitor Cells With Long-Term Proliferative Ability In Vitro and In Vivo Have the Phenotype CD34+/CD71−/HLA-DR−

Acute myeloid leukemia (AML) occurs as the result of malignant transformation in a hematopoietic progenitor cell, which proliferates to form an accumulation of AML blasts. Only a minority of these AML cells are capable of proliferation in vitro, suggesting that AML cells may be organized in a hierarchy, with only the most primitive of these cells capable of maintaining the leukemic clone. To further investigate this hypothesis, we have evaluated a strategy for purifying these primitive cells based on surface antigen expression. As an in vitro endpoint, we have determined the phenotype of AML progenitor cells which are capable of producing AML colony-forming cells (CFU) for up to 8 weeks in suspension culture (SC) and compared the phenotype with that of cells which reproduce AML in nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice. AML cells were fluorescence-activated cell sorted (FACS) for coexpression of CD34 and CD71, CD38, and/or HLA-DR and the subfractions were assayed in vitro and in vivo at various cell doses to estimate purification. While the majority of primary AML CFU lacked expression of CD34, most cells capable of producing CFU after 2 to 8 weeks in SC were CD34+/CD71−. HLA-DR expression was heterogeneous on cells producing CFU after 2 to 4 weeks. However, after 6 to 8 weeks in SC, the majority of CFU were derived from CD34+/HLA-DR− cells. Similarly, the majority of cells capable of long-term CFU production from SC were CD34+/CD38−. Most cells that were capable of engrafting NOD/SCID mice were also CD34+/CD71− and CD34+/HLA-DR−. Engraftment was not achieved with CD34+/CD71+ or HLA-DR+subfractions, however, in two patients, both the CD34+and CD34− subfractions were capable of engrafting the NOD/SCID mice. A three-color sorting strategy combining these antigens allowed approximately a 2-log purification of these NOD/SCID leukemia initiating cells, with engraftment achieved using as few as 400 cells in one experiment. Phenotyping studies suggest even higher purification could be achieved by combining lack of CD38 expression with the CD34+/CD71− or CD34+/HLA DR− phenotype. These results suggest that most AML cells capable of long-term proliferation in vitro and in vivo share the CD34+/CD71−/HLA-DR− phenotype with normal stem cells. Our data suggests that in this group of patients the leukemic transformation has occurred in a primitive progenitor, as defined by phenotype, with some degree of subsequent differentiation as defined by functional assays.

Most Acute Myeloid Leukemia Progenitor Cells With Long-Term Proliferative Ability In Vitro and In Vivo Have the Phenotype CD34+/CD71−/HLA-DR−

Acute myeloid leukemia (AML) occurs as the result of malignant transformation in a hematopoietic progenitor cell, which proliferates to form an accumulation of AML blasts. Only a minority of these AML cells are capable of proliferation in vitro, suggesting that AML cells may be organized in a hierarchy, with only the most primitive of these cells capable of maintaining the leukemic clone. To further investigate this hypothesis, we have evaluated a strategy for purifying these primitive cells based on surface antigen expression. As an in vitro endpoint, we have determined the phenotype of AML progenitor cells which are capable of producing AML colony-forming cells (CFU) for up to 8 weeks in suspension culture (SC) and compared the phenotype with that of cells which reproduce AML in nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice. AML cells were fluorescence-activated cell sorted (FACS) for coexpression of CD34 and CD71, CD38, and/or HLA-DR and the subfractions were assayed in vitro and in vivo at various cell doses to estimate purification. While the majority of primary AML CFU lacked expression of CD34, most cells capable of producing CFU after 2 to 8 weeks in SC were CD34+/CD71−. HLA-DR expression was heterogeneous on cells producing CFU after 2 to 4 weeks. However, after 6 to 8 weeks in SC, the majority of CFU were derived from CD34+/HLA-DR− cells. Similarly, the majority of cells capable of long-term CFU production from SC were CD34+/CD38−. Most cells that were capable of engrafting NOD/SCID mice were also CD34+/CD71− and CD34+/HLA-DR−. Engraftment was not achieved with CD34+/CD71+ or HLA-DR+subfractions, however, in two patients, both the CD34+and CD34− subfractions were capable of engrafting the NOD/SCID mice. A three-color sorting strategy combining these antigens allowed approximately a 2-log purification of these NOD/SCID leukemia initiating cells, with engraftment achieved using as few as 400 cells in one experiment. Phenotyping studies suggest even higher purification could be achieved by combining lack of CD38 expression with the CD34+/CD71− or CD34+/HLA DR− phenotype. These results suggest that most AML cells capable of long-term proliferation in vitro and in vivo share the CD34+/CD71−/HLA-DR− phenotype with normal stem cells. Our data suggests that in this group of patients the leukemic transformation has occurred in a primitive progenitor, as defined by phenotype, with some degree of subsequent differentiation as defined by functional assays.

CD5 positive breast carcinoma in a patient with untreated chronic lymphocytic leukaemia: molecular studies of chromosome 13q

A 67 year old woman presented with a right breast lump which proved to be a grade 2 invasive ductal carcinoma with axillary lymph node metastasis. She had a five year history of CD5 positive chronic lymphocytic leukaemia, which never required treatment. Immunoperoxidase stains for CD5, using the monoclonal antibody NCL-CD-54C7, showed that there was extensive infiltration of axillary lymph nodes with CD5 positive B lymphocytes. Strong staining for CD5 was also seen in the carcinoma cells within the breast and lymph node metastases. It has recently been suggested that there is a tumour suppresser locus in chronic lymphocytic leukaemia at 13q12.3 near or at the BRCA2 locus. Deletion of regions on chromosome 13q containing the BRCA2 and RB1 genes has also been reported in sporadic breast cancers. These observations suggest that there may be a link between these two diseases acting through chromosome 13, but amplification of several microsatellite repeat markers failed to show any loss of heterozygosity or repeat instability at either these or several other loci on chromosome 13. Examination of additional such cases is needed to perform a more comprehensive study of the significance of positive CD5 staining of breast carcinoma.

Alteration of T-cell subsets in the lymph nodes from cats infected with feline immunodeficiency virus

Alterations of T-cell subsets in the lymph nodes from FIV-infected cats in various clinical disease stages were examined histologically. In the early stage of infection (AP stage), follicular hyperplasia accompanied by expansion of the paracortical area was observed. Follicular involution and depletion with reduced paracortical area was observed in the ARC and AIDS stage nodes. The maximum section area of the entire popliteal lymph node was expanded significantly in the AP nodes. The paracortical area expanded in the AP nodes and decreased in the ARC and AIDS stage nodes. The cell density in the paracortical area in the AP nodes did not show a significant increase, while there was a significant reduction in the ARC and AIDS stage nodes. The lymph node CD4/CD8 ratio in the AP and ARC stages significantly decreased as compared with that of uninfected control cats, but conversion of the ratio was not seen. The estimated total numbers of CD4+ and CD8+ cells in the maximum section were increased in the AP stage but significantly decreased in the ARC and AIDS stages. Our study indicated that the lymphocyte depletion in the terminal ARC and AIDS stages of FIV infection was associated with both CD4+ cells and CD8+ cells. Findings obtained in this study might provide useful information for studying the pathophysiology of FIV infection.

CD5 B cells in autoimmune and non immune-mediated thyroid dysfunctions

In a previous study we demonstrated a significant increase of CD5+ B subset in patients with Graves' disease (GD) compared with normal controls. The aim of this study was to compare the percentage of CD5+ B and CD5- B cells in GD with that in different forms of autoimmune and non immune-mediated thyroid diseases. Seventy-two patients were studied: 28 patients with GD, 20 with silent thyroiditis (ST), 12 with Hashimoto's disease (HD), and 12 subjects affected by hyperthyroidism due to toxic adenoma (TA). Eleven out of 28 patients with GD were also evaluated after six months of methimazole treatment. The study was performed by cytometric analysis. In GD the percentage and the absolute number of CD5+ B cells were significantly increased compared with normal controls (42.5 +/- 18.2% versus 19 +/- 6.3%, p < 0.0001; 142 +/- 153.3/cmm versus 46.9 +/- 22/cmm, p < 0.003, respectively. CD5+ B cells tended to normalise after six months of treatment. In ST the percentage of CD5+ B cells was increased (28.6 +/- 10.2%); conversely the absolute number was in the normal range. Patients affected by HD did not show any significant modification in B cells and their subsets in comparison with controls. In TA, CD5+ B were 7.6 /- 4.4% and 14.3 /- 10.9/cmm. Our results demonstrated a marked increase in both percentage and absolute number of CD5+ cells, only in active GD. The expansion of CD5+ B cells could play a role in the immune imbalance present in this disease.

Structure and function of natural antibodies

Natural antibodies arise independently of known antigenic stimulation, are mostly IGM, polyreactive, and are generally encoded by V genes in germline configuration. Polyreactive IgM natural antibodies are produced by mainly B-1 cells which account for most of the B cell repertoire in the fetus and neonate, and possibly play a major role in the development and physiology of the human B cell repertoire. Although endowed with self-reactivity, natural antibodies also bind exogenous antigens [73, 74]. Exposure to environmental antigens is not necessary for the emergence of natural antibody-producing cell precursor clones to exogenous antigens, as suggested by the significant population of B cells capable of producing antibodies to a variety of bacterial antigens in germ-free animals. Because of their ability to bind a variety of exogenous antigens, including those on bacteria and viruses, natural antibodies play a major role in the primary line of defense against infections. A central issue related to the understanding of the physiopathologic roles of natural antibodies is whether precursors of cells producing natural antibodies, B-1a and B-1b lymphocytes, are capable of undergoing an antigen-driven clonal selection process, thereby producing autoantibodies with a high affinity for the selecting antigen. In this respect, we have clearly established that B-1 cells can express a hypermutation mechanism similar to that of conventional (B-2) cells. Furthermore, we have shown by gene shuffling, site-directed mutagenesis, and in vitro human Ig gene expression, that the main structural correlate for antibody polyreactivity is provided by the somatically generated H chain CDR3. We have also shown that this Ig V region provides the main structural correlate for antigen-binding in monoreactive antigen-induced autoantibodies. These findings in the human are at the basis of our proposed structure-function model in which the antigen binding features of the germline template antibody are dictated by the somatically generated H chain CDR3, and perhaps, but at a lower degree, L chain CDR3; the point-mutation changes underlying the antigen-driven affinity maturation process would impact mainly the Ig V gene encoded segments. This structure-function model is being tested in our laboratory by analyzing the antigen binding activity of somatically mutated polyreactive autoantibodies that have been structurally reverted to their original putative unmutated configuration. Precise identification of the Ig gene and/or somatic recombination products mediating recruitment of unmutated B cell clonotypes, as well as those that are preferentially modified by an antigen-dependent selection process, should further our understanding of the mechanisms that shape the B cell repertoire in development and disease.

Evidence for a trans-acting activator function regulating the expression of the human CD5 antigen

Interspecies somatic cell hybrids were generated by fusing the mouse T-lymphoma cell line, BW5147, with normal human T lymphocytes at different stages of differentiation. Thymocytes, activated peripheral T lymphocytes, or an activated T-cell clone were used as human partners, respectively, in three independent fusions. Irrespective of the human cell partner used for fusion, a certain number of hybrids lost CD5 surface expression over a period of time in culture. Analysis at the phenotype and genetic level showed that lack of CD5 expression was due neither to segregation of human autosome 11, on which the CD5 gene has been mapped, nor to deletion of the CD5 structural gene. Furthermore, loss of CD5 surface expression correlated with the absence of specific mRNA. Since these hybrids preferentially segregate human chromosomes, these results indicate the existence of a non-syntenic trans-active locus, or loci, positively controlling the expression of the human CD5 gene.

Discrimination between two subsets of porcine CD8+ cytolytic T lymphocytes by the expression of CD5 antigen

Previous work has revealed striking differences in the peripheral T-lymphocyte compartments of swine compared to other species. The key difference is the existence of four T-lymphocyte subpopulations defined by their CD4/CD8 expression. Besides this difference in the CD4/CD8 antigen expression, we report here another unusual antigen distribution on porcine extrathymic T lymphocytes: the expression of the 63,000 MW CD5 antigen. In porcine thymus the CD5 antigen shows a biphasic antigen density, whereas the majority of thymocytes are characterized by an intermediate CD5 expression. In the extrathymic T-lymphocyte compartment, CD5 also shows a heterogeneous antigen distribution as defined by three subsets: CD5high, CD5dim and CD5- T lymphocytes. Analyses of the CD5 expression on the four CD4/CD8-defined peripheral T-cell subpopulations revealed that all CD4+ T lymphocytes, CD4+ CD8+ as well as CD4+ CD8- T lymphocytes, belonged to the subset with high CD5 antigen density. The CD4- CD8- subpopulation, containing in the majority T-cell receptor (TcR) gamma delta T lymphocytes, was characterized by dim CD5 expression. The most notable difference was the division of the CD4- CD8+ cytolytic T-lymphocyte subpopulation into two CD5-defined subsets: CD4- CD5- CD8+ lymphocytes with spontaneous cytolytic activity against tumour cells, and CD4- CD5+ CD8+ T lymphocytes with major histocompatibility complex (MHC)-restricted cytolytic function. Thus, the porcine CD5 antigen is an important marker to discriminate between CD5- CD8+ natural killer (NK) cells and CD5+ CD8+ progenitors of MHC-restricted cytolytic T lymphocytes.

Variable effects of tamoxifen on human hematopoietic progenitor cell growth and sensitivity to doxorubicin

To determine the influence of tamoxifen on the drug sensitivity of normal human hematopoietic progenitor cells, T-cell- and adherent-cell depleted human bone marrow mononuclear cells (T-, Ad-) were exposed in vitro to 5 microM tamoxifen for 24 h. The effects of tamoxifen were highly variable, as exposure to tamoxifen produced an increase (97% +/- 12.3%) in the growth of day-12 committed myeloid progenitors (CFU-GM) in only four of ten experiments utilizing bone marrow from different donors. When T-, Ad- myeloid progenitor cells treated with tamoxifen were subsequently exposed to doxorubicin, 7 of 14 experimental samples studied demonstrated a net increase in the number of surviving clonogenic cells as compared with cells exposed to doxorubicin alone. Tamoxifen also stimulated the growth of a more purified (CD34(+)-selected) progenitor cell population in four of four experiments (by 62.5% +/- 4.9%) but did not increase the survival of these cells upon exposure to doxorubicin; in fact, in five of ten experimental samples, tamoxifen enhanced cell sensitivity to doxorubicin. Taken together, these observations indicate that tamoxifen produces variable stimulation of committed myeloid progenitor cell growth in vitro. Furthermore, while under some circumstances, tamoxifen appears to have the capacity to enhance CFU-GM survival in the presence of doxorubicin, this drug combination may also result in enhanced toxicity to normal bone marrow progenitors.

Putative prethymic T cell precursors within the early human embryonic liver: a molecular and functional analysis

Hematopoietic cells present in the liver in early human fetal life were characterized by phenotypic analysis using a broad panel of monoclonal antibodies. Expression of very late antigen 4 and leukocyte function-associated antigen 3 cell adhesion receptors and 4F2 cell activation molecules was found in all fetal liver hematopoietic cells before acquisition of T cell-, B cell-, or myeloid-specific surface markers, and before the time of intrathymic colonization. Molecular studies showed that expression of the interleukin 2 receptor beta (IL-2R beta) also occurred in the embryonic liver at this early ontogenic stage. In contrast, no expression of IL-2R alpha or IL-2 transcripts was found in fetal liver cells, whereas transcription of the IL-4 gene was detected in a small fetal liver cell subset. Putative T cell precursors were identified among the hematopoietic fetal liver cells by the expression of genes encoding the gamma, delta, epsilon, and zeta invariant chains of the CD3-T cell receptor (TCR) complex. However, no transcription of the polymorphic alpha and beta TCR genes was detected. Functional in vitro assays further demonstrated that fetal liver hematopoietic cells from those early embryos were capable of proliferating in response to T cell growth factors, including IL-4 and IL-2. However, whereas IL-4-induced proliferation paralleled the appearance in vitro of CD45+CD7-CD4dull cells expressing the CD14 myeloid antigen, as well as of CD34+ primitive hematopoietic progenitors, differentiation into CD45+CD7+CD8+CD3- immature T cells was observed when using IL-2. Moreover, coculture with thymic epithelial cell monolayers provided additional evidence that early fetal liver hematopoietic cells may include very primitive T cell precursors, which were able to differentiate in vitro into TCR alpha/beta+ mature T cells. Therefore, our results indicate that, after triggering of the T cell-specific maturation program in primitive fetal liver hematopoietic progenitors, specific signals provided intrathymically by epithelial cells may fulfill the requirements to drive terminal differentiation of prethymically committed T cell precursors.

Detection of, and anti-collagen antibody produced by, CD5-positive B cells in inflamed gingival tissues

This study was performed to investigate the frequency and distribution of CD5-positive (CD5+) B cells in inflamed gingival tissues using flow cytometric and immunohistochemical analyses. The ability of CD5+ B cells to produce anti-type I collagen antibody was also examined. CD5+ B cells expressed "low" fluorescence intensity in the peripheral blood of both healthy subjects and patients with adult periodontitis. However, in inflamed gingival tissues the intensity of this surface marker was high. The percentage of B cells bearing CD5 surface marker was statistically higher in gingiva than in peripheral blood obtained from both the patients and healthy subjects. These CD5+ B cells were observed in gingival subepithelial connective tissues from the bottom to the middle of the periodontal pocket. This area showed destruction of collagen fibers and dense cell infiltrations. Anti-collagen IgG antibody level in patients' gingival crevicular fluids (GCF) was higher than that in sera from healthy subjects, and slightly higher than in autologous sera. IgM anti-collagen antibody in GCF was lower than in autologous sera and in sera from healthy subjects. EBV-transformed CD5+ B cells produced considerably more IgM and IgG antibody to collagen than CD5- B cells. Therefore CD5+ B cells may contribute to the pathogenesis of inflamed gingival tissues.

Novel responses of human skin to intradermal recombinant granulocyte/macrophage-colony-stimulating factor: Langerhans cell recruitment, keratinocyte growth, and enhanced wound healing

Recombinant granulocyte/macrophage-colony-stimulating factor (rGM-CSF), prepared from Chinese hamster ovary (CHO) cells and Escherichia coli, was administered to 35 patients with the borderline and polar lepromatous forms of leprosy by the intradermal and subcutaneous routes at doses of 7.5-45.0 micrograms/d for 10 d. With each of these doses and routes, increases in the number of circulating eosinophils were noted. After the intradermal injection, the local skin sites demonstrated zones of roughening and micronodularity that appeared within 24-48 h and persisted for more than 6 d. Reinjection of sites led to enhanced areas of epidermal reaction. GM-CSF prepared from CHO cells was a more potent inducer of this effect. GM-CSF given by the subcutaneous route, at higher doses, failed to initiate these changes. At the microscopic level, the epidermis became thickened (+75%) with increased numbers and layers of enlarged keratinocytes. These contained increased numbers of ribosomes and prominent nucleoli, and were imbedded in a looser meshwork of the zona Pellucida. The modified keratinocytes remained MHC class II antigen negative throughout the course of the response. A major change in the dermis was the progressive accumulation of CD1+, Birbeck granule-positive cells. These Langerhans were recognizable at 48 h after intradermal injection and reached maximum numbers by 4 d. During this period the number of epidermal Langerhans cells remained relatively constant. No increment in dermal Langerhans cells occurred when GLM-CSF was injected by the subcutaneous route. No appreciable increase in the numbers of T cells and monocytes was noted, and granulocytes and eosinophils were largely present within the dermal microvasculature. 4-mm punch biopsies taken from injected sites and adjacent controls were compared in terms of the rapidity of wound healing. 22 of 26 sites demonstrated more rapid filling and hemostasis, whereas four were equivalent to controls. We conclude that rGM-CSF, when introduced into the skin, leads to enhanced keratinocyte growth, the selective recruitment of Langerhans cells into the dermis, and enhanced wound healing of the prepared site. There was no evidence of an enhanced cell-mediated response to Mycobacterium leprae, and bacillary numbers remained unchanged.

Detection, isolation and functional studies of CD25+ T cells in lymph nodes involved by B-cell non-Hodgkin's lymphomas

We searched for the presence of IL2 receptor (CD25) on T cells as an activation marker in lymph nodes involved by B-cell non-Hodgkin's lymphomas (B-NHL). In 26 malignant lymph nodes studied, the number of CD25+ T cells among total T cells was usually low when assessed by immunofluorescence analysis (mean +/- SD: 6.7% +/- 11.2%), but greatly increased when an immunomagnetic rosette method was used (mean +/- SD: 17.5% +/- 16.6%). In six cases, CD25-/CD25/CD25+ cells were isolated by immunomagnetic separation, with a purity greater than 97% for both populations. Expansion of CD25-/CD25+ T cells was obtained with IL2 and PHA, then conditioned media (CM) were prepared. No IL2 activity was found in CM from both CD25-/CD25+ T cells when tested on CTLL2 cells. BCGF and BCDF mu/gamma activities were assayed on normal B cells stimulated with soluble or insolubilized anti-mu antibodies(BCGF) or with Cowan I (BCDF). Results of production of all these activities were comparable for both populations, and thus do not favour the possibility that CD25+ T cells closely associated with malignant B-NHL cells in lymph nodes may influence their proliferation (BCGF) or expression/secretion of heavy chain isotype (BCDF mu/gamma).

Immobilized anti-CD5 together with prolonged activation of protein kinase C induce interleukin 2-dependent T cell growth: evidence for signal transduction through CD5

Monoclonal antibodies (mAb) identifying the CD5 antigen were used to stimulate human peripheral blood T lymphocytes. Three out of three anti-CD5 mAb, 10.2, OKT1 and anti-Leu-1 induced vigorous proliferation of purified T cells in the presence of 1.6 nM phorbol 12-myristate 13-acetate (PMA). Immobilization of anti-CD5 mAb on a solid support was necessary for the induction of a proliferative response. Neither 1.6 nM PMA, nor immobilized anti-CD5 mAb were mitogenic as a sole stimulus. mAb identifying CD4, CD7, CD11a, CD18, and major histocompatibility complex class I molecules were not comitogenic with PMA. Anti-CD5/PMA-induced cell proliferation proceeded by an interleukin 2 (IL 2)-dependent mechanism, as was demonstrated by the cell surface expression of the p55 chain of the IL 2 receptor (IL 2R), the production of IL 2 and the inhibition of the proliferative response by anti-IL 2R mAb anti-Tac. There was no strict requirement for detectable numbers of monocytes, although cell proliferation could be enhanced by the monocyte-derived cytokines IL 1 and IL 6. Phorbol 12,13-dibutyrate and mezerein could substitute for PMA in this activation pathway, but synthetic diacylglycerols and phorbol esters that do not activate protein kinase C (PKC) could not, indicating a need for prolonged activation of PKC. T cells activated by anti-CD5/PMA are sensitive to inhibition by cyclosporin A (CsA) and by prostaglandin E2 (PGE2). This contrasts with anti-CD28/PMA-induced T cell proliferation, which is resistant to CsA and PGE2. Cell surface expression of CD5 was strongly up-regulated by PMA, whereas CD3 expression was down-regulated. We conclude that T cell activation can be triggered by engagement of CD5 by immobilized anti-CD5 mAb, combined with prolonged activation of PKC. These data support a role for CD5 as an independent signal transducing molecule.

A monoclonal antibody to human leukocyte common antigen, SHL-1, and its use for formalin-fixed, paraffin-embedded tissues

The authors describe a newly characterized murine monoclonal antibody to the human leukocyte surface antigen, SHL-1. The antigen belongs to the leukocyte common antigen (LCA) family, and its molecular weight is about 180,000 daltons, which is similar to that of some previously characterized LCAs. The SHL-1 antigen is resistant to conventional tissue-fixation and embedding procedures. This antibody can therefore be used in the immunohistochemical staining of paraffin-embedded tissue sections. Wide screening with a sufficient number of both fresh and routinely processed paraffin-embedded tissues was done with indirect immunoperoxidase technique. With this procedure, SHL-1 labeled the majority of normal leukocytes and hematopoietic malignancies. Some B-cell malignancies were not stained with this antibody. The non-hematologic malignancies posing diagnostic problems of differentiation from lymphomas or leukemias were completely negative to SHL-1. The immunoreactivity to SHL-1 of samples from 24 leukemic patients and 15 human tumor cell lines was determined by the immunofluorescence method. Of 24 leukemic preparations, 23 were strongly reactive to this antibody. One case of B-cell leukemia did not react with SHL-1. No immunoreactivity was demonstrated in non-hematopoietic tumor cell lines. The overall reaction pattern of SHL-1 proved its usefulness in both diagnostic and research practice in hematological disorders. This antibody detected cell surface antigens of the T cell series more effectively than those of the B-cell series in terms of the positive number of cells and mean fluorescence intensity.

Effect of pharmacologic manipulation of protein kinase C by phorbol dibutyrate and bryostatin 1 on the clonogenic response of human granulocyte-macrophage progenitors to recombinant GM-CSF

The effect of pharmacologic manipulation of protein kinase C (PK-C) activity on the response of committed human myeloid progenitor cells (CFU-GM) to recombinant human granulocyte-macrophage colony stimulating factor (rGM-CSF) was assessed. Coadministration of the PK-C activating agents, phorbol dibutyrate (PDBu) or bryostatin 1, with rGM-CSF resulted in a dose-dependent and, under some conditions, highly synergistic increase in the number of CFU-GM. With optimal combinations, colony formation far exceeded that which could be obtained with high concentrations of rGM-CSF alone. High concentrations of PDBu (e.g. greater than or equal to 50 nM), but not bryostatin 1, completely inhibited the CFU-GM response. These inhibitory effects could be reversed by bryostatin 1, but not by high concentrations of rGM-CSF. Bryostatin 1 also potentiated colony formation in response to rGM-CSF, and blocked the inhibitory effects of high concentrations of PDBu in bone marrow cells highly enriched for progenitors bearing the MY-10 antigen. The increase in CFU-GM induced by PDBu or bryostatin 1 was associated with little change in the morphologic type of colony observed. Continuous exposure of cells to the calcium ionophore, ionomycin (500 nM), reduced the number of granulocyte-macrophage colonies, but produced little change in the concentration-response of rGM-CSF and PK-C activating agents. Finally, the PK-C inhibitors H-7 and tamoxifen, when administered at concentrations exhibiting minimal inhibitory effects in the presence of rGM-CSF alone, led to no change or small increases in the numbers of colonies formed in response to rGM-CSF and bryostatin-1, and a substantial increase in the number of colonies formed in the presence of rGM-CSF and PDBu. These results suggest that PK-C activation may play a complex role in regulating the response of normal myeloid progenitors to growth factors such as rGM-CSF. They also raise the possibility that under some circumstances the phorbol ester PDBu may trigger events that inhibit the growth of myeloid progenitors, and that this process may be blocked by bryostatin 1.

Reduction of major histocompatibility complex class I antigens on invasive and high-grade transitional cell carcinoma

We examined immunohistologically the expression of major histocompatibility complex (MHC) class I and II antigens, which play important roles in immune reactions, on transitional cell carcinoma (TCC). When stained with monoclonal antibody W6/32 against class I antigens, reduced staining was observed in 34 of 46 TCCs and was virtually absent in 15 of these. The cases showing reduced staining were much more frequent (29 of 34) in high- to moderate-grade than in low-grade TCC. Furthermore, class I antigens were reduced in 18 of 19 invasive TCCs, but in 16 of 27 superficial TCCs. Thus, the reduction of class I antigens was correlated significantly with a decreased degree of tumour cell differentiation and the presence of invasion. Class II antigens on TCC showed variable expression and were not related to tumour grade or stage.

Identification of lymphocyte antigens in human dental pulps

The aim of the experiment was to study the immune reaction of cells in both healthy and inflamed human dental pulps. For this it was necessary to identify, in particular, populations of lymphocytes in the pulp, and also other cells involved in the immune reaction. By using monoclonal antibodies which specifically recognize subpopulations of the T lymphocytes, we were able: 1) to directly determine the phenotype of the cells of the pulp, 2) to examine the interactions of the different cell populations. The study was based on 30 permanent human dental pulps and the method was that of indirect immunofluorescence on frozen sections. The monoclonal antibodies used were the antibodies OKT and anti-Leu of types anti-Leu1, anti Leu3a, OKT4, OKT8 and OK1a. The results obtained were evaluated statistically. Two important points stand out from this study: 1) in the healthy samples there is preferential localization of lymphocytes at the periphery of the pulp and 2) there is a predominance of the OKT8+ cytotoxic suppressor subpopulation in both the healthy and the inflamed pulps.

Phenotypic analysis of human peripheral blood lymphocytes by automatic sampling flow cytometry after stimulation with mitogens or allogeneic cells

Human peripheral blood lymphocyte (PBL) phenotypes have been analyzed before and after stimulation with phytohemagglutinin (PHA), concanavalin A (ConA) and pokeweed mitogen (PWM) for 3 days and in mixed lymphocyte culture (MLC) for 7 days. PBL labeled with each of 10 fluorescent monoclonal antibodies were automatically sampled for flow cytometry from 96-well microtiter plates using a microsample delivery system. The reference phenotypic ranges were determined in fresh cells and control cultures. PHA was mostly mitogenic for T PBL bearing the CD3, CD5, CD7, CD8 and CD25 differentiation clusters, and a low density of CD1 and CD4 had a small effect on human natural killer cells (HNK) and also did not stimulate B (CD19) and HLA-DR+ PBL. There was an incomplete phenotypic overlapping between PHA- and ConA-stimulated cultures, ConA being more mitogenic for CD4 and less mitogenic for CD8 PBL. The mitogenic effect of PWM was evident on CD3, CD5, CD7, CD4, CD25 and CD8, but not on HNK, HLA-DR and CD19 B PBL, which presumably had already differentiated into antibody-secreting cells. After MLC stimulation all T, B and HNK PBL subsets tested were increased, but the cells bearing CD1, CD4, CD5, CD7, CD25, HNK, CD19 and HLA-DR had the greatest proliferation with respect to the unmixed control PBL. The present approach to the phenotyping of PBL subsets could offer more complete and accurate data for monitoring and follow-up of patients in transplantation and immunopathology hospital wards.

Establishment and characterisation of an Epstein-Barr virus negative B immunoblastic lymphoma cell line

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A correlation between serum immunosuppressive acidic protein and altered immunocompetence in patients with brain tumours

The present investigation was conducted to document a correlation between the serum levels of immunosuppressive acidic protein (IAP) and depressed lymphocyte responsiveness to mitogens in vitro in patients with intracranial tumours, and to delineate the possible roles of IAP upon immunocompetence in these patients. It was thought that high concentrations of IAP present in the serum of brain-tumour patients may play a significant role in the immunosuppression seen in this patient population. The effect of IAP upon mitogen-stimulated lymphocyte function was evaluated by tritiated (3H)-thymidine incorporation. Lymphocytes from both 30 patients with intracranial tumours and 30 normal individuals were incubated for 90 hours in culture medium in the presence of three mitogens: phytohaemagglutinin (PHA), concanavalin A (Con A), and pokeweed mitogen (PWM). Lymphocytes obtained from patients with brain tumours and cultured in autologous serum displayed a significant depression of 3H-thymidine incorporation, as was observed in previous studies. In addition, a significant suppression of mitogen-induced activation of the normal lymphocytes was demonstrated in the presence of allogeneic patients' serum and the percentage of inhibition was found significantly proportional to the IAP concentrations. Furthermore it was also demonstrated that increased levels of serum IAP could significantly correlate with two in vivo aspects of impaired cellular immunity: the decreased lymphocyte counts in the peripheral blood and diminished cutaneous delayed hypersensitivity reactions measured by purified protein derivative (PPD) skin test reactivity. On the other hand, an attempt was also made to investigate changes in humoral immunity and immunoglobulin concentrations were observed not to correspond to the serum IAP levels. These studies suggest a possible connection between serum IAP levels and altered cellular immune competence in brain-tumour patients.

Immunophenotype analysis of B-CLL lymphoma and immunocytoma

The differential diagnosis between lymphocytic lymphoma of the B-CLL type and immunocytoma (IC) can be difficult when it is based only upon morphological criteria. With the aim of improving the distinction between these subgroups, frozen sections of lymph nodes or other biopsied tissues from 14 cases of B-CLL and 16 cases of IC were investigated according to immunophenotype. A panel of 13 B cell-associated and 2 T cell-associated monoclonal antibodies was used. All but one of the B-CLL cases were FMC7-, while 14/16 IC cases were FMC7+ (p less than 0.001). The two negative IC cases were both of the lymphoplasmacytic type, claimed to be "more differentiated" than the lymphoplasmacytoid type. We suggest that the cells in these cases are mature enough to have lost their FMC7 positivity, similar to plasma cells. There was also a statistically significant (p less than 0.01) difference, although not as pronounced, for the anti-CD38 antibody (Leu-17, B-CLL: 3/14, IC: 10/16 positive). No significant difference in expression of determinants was found for any of the other antibodies.

Definition of a population of CD4-8- T cells that express the alpha beta T-cell receptor and respond to interleukins 2, 3, and 4

Whereas most T cells express surface CD4 or CD8 molecules, a minority lacks both. CD4-8- cells usually express the gamma delta T-cell receptor, but here we describe a population of CD4-8- T cells from the peripheral blood that express the alpha beta heterodimer. These cells have different surface antigens than gamma delta+ T cells, expressing CD5 but lacking CD16, and differ in function from gamma delta+ T cells. CD4-8- alpha beta+ cells lack non-major histocompatibility complex-restricted cytolytic function but can be induced to lyse their target cells after activation of their T-cell receptors. A peculiar characteristic of these cells is their responsiveness to interleukin 3. Since these cells have not altered their phenotype or function over a 12-month period in culture, they appear to be mature T cells. The results indicate that normal human peripheral blood contains two subsets of CD4-8- T cells, expressing either gamma delta or alpha beta receptors, that differ in function, phenotype, and growth control.

Effect of multiple interferon gamma injections on the disposal of Mycobacterium leprae

The effect of multiple intradermal injections (four to six) of 10 micrograms of interferon gamma on the number of Mycobacterium leprae in the skin of patients with polar lepromatous leprosy and borderline lepromatous leprosy was evaluated. To achieve a maximum zone of induration and cell emigration a preparatory dose of the lymphokine was required. A second group of three injections, given 3-4 days after the initial series, resulted in lesser degrees of induration and was more in keeping with a partial local hyporesponsive state. A marked emigration of T cells and monocytes into the dermis resulted from injections of interferon gamma and persisted for greater than 21 days. A preponderance of CD4+ cells in the infiltrate was seen within a few days and CD4/CD8 ratios remained elevated for greater than 5 weeks. The bacillary load of injected sites evaluated 21 days after lymphokine administration was reduced in 14/17 patients by factors ranging from 5- to 1000-fold. This occurred predominantly within diffuse lesions and occurred rarely in nodular sites. Biopsy samples of injected sites taken 6 months later demonstrated progressive 10-fold reductions in bacilli and the continued presence of a granulomatous response.

DNA fragmentation and cell death mediated by T cell antigen receptor/CD3 complex on a leukemia T cell line

An anti-T cell receptor (TcR) monoclonal antibody (mAb), LC4, directed against a human leukemic T cell line, SUP-T13, caused DNA fragmentation ("apoptosis") and cell death upon binding to this cell line. Cross-linking of receptor molecules was necessary for this effect since F(ab')2, but not Fab', fragments of LC4 could induce cell death. Five anti-CD3 mAb tested also caused apoptosis, but only when they were presented on a solid phase. Interestingly, soluble anti-CD3 mAb induced calcium flux and had an additive effect on the calcium flux and interleukin 2 receptor expression induced by LC4, but these anti-CD3 mAb reversed the growth inhibition and apoptosis caused by LC4. The calcium ionophore A23187, but not the protein kinase C activator phorbol 12-myristate 13-acetate (PMA), also induced apoptosis, suggesting that protein kinase C activation alone does not cause apoptosis, although PMA is growth inhibitory. These results suggest that two distinct biological phenomena can accompany stimulation of the TcR/CD3 complex. In both cases, calcium flux and interleukin 2 receptor expression is induced, but only in one case is apoptosis and cell death seen. The signal initiating apoptosis can be selectively prevented by binding CD3 portion of the receptor in this cell line. This difference in signals mediated by the TcR/CD3 complex may be important in explaining the process of thymic selection, as well as in choosing anti-TcR mAb for therapeutic use.

In situ study of haemopoiesis in human fetal liver

The anatomy of haemopoietic cells in human fetal liver was examined using immunohistological techniques on frozen sections of 31 fetuses (10-28 weeks gestational age). The immunohistological findings were consistent with reported cell suspension data. With regard to the location of haemopoietic activity no particular relationship existed between the various haemopoietic cell lineages. A large number of proliferating cells was present; only a few of these were reactive with haemopoietic progenitor cell monoclonal antibodies (MoAb) CD34. A population of haemopoietic cells expressed CD43 antigen (MoAb MT1) alone or together with anti-vimentin MoAb reactivity; this population needs further delineation. Erythropoiesis and myelopoiesis occurred in clusters around sinusoids and portal triad vessels respectively. Lack of MoAb reacting exclusively with early developmental stages of erythropoiesis and myelopoiesis precluded dissection of these lineages. Lymphopoiesis occurred in a loosely scattered pattern without any sign of focal development. Pre-B and B-cell numbers increased with gestational age. Cells expressing markers of more mature B cells (surface IgD, CD35, and CD21) were rare. Also, few cells reacted with mature T-cell markers, but CD7+ cells were obviously present. This expression of CD7 on haemopoietic fetal liver cells suggests that T-cell precursors develop in fetal liver as well as B cells.

Influence of Mycobacterium leprae and its soluble products on the cutaneous responsiveness of leprosy patients to antigen and recombinant interleukin 2

Experiments were carried out in the skin of patients with leprosy to examine whether suppressor cell populations either exist in the skin of multibacillary lepromatous leprosy patients, can be activated with antigen, or are induced to emigrate into a cutaneous site from the circulation. For this purpose, purified protein derivative of tuberculin, a delayed-type antigen that generates a cell-mediated immune response, was introduced into the skin alone or with nonviable Mycobacterium leprae bacilli. Areas of induration and the resulting numbers and phenotypes of emigratory cells were not influenced by M. leprae and its products. Further studies examined the ability of M. leprae and its soluble products to modify the cutaneous response to intradermal injection of recombinant interleukin 2 (IL-2), a lymphokine that mimics a cell-mediated response. Neither the simultaneous injection of M. leprae and IL-2, nor the prior injection of M. leprae followed in 2 days by IL-2, nor the prior administration of IL-2 followed in 4 days by M. leprae, into the same skin site, modified the zone of induration generated by IL-2. In addition, the immunocytochemical and histopathological evaluation of biopsy specimens of skin sites showed no difference between sites injected with IL-2 and sites injected with IL-2 and M. leprae. We conclude that suppressor T cells, if they exist, do not influence the gross or microscopic responsiveness of a cell-mediated skin reaction to antigen and IL-2. IL-2 did, however, enhance the responsiveness of skin-test-positive tuberculoid patients and family contacts to M. leprae antigens by a synergistic effect on the zone of induration and local cell accumulation.

Evidence for a novel picornavirus in human dermatomyositis

We prepared RNA probes from cloned segments of human and murine enteroviruses (EVs) for in situ hybridization of skeletal muscle biopsies from patients with dermatomyositis (DM), polymyositis, other inflammatory myopathies, and noninflammatory muscle diseases, and from normal control subjects. A probe derived from Theiler's murine encephalomyelitis virus (TMEV) detected viral RNA within mononuclear cells of the interstitial connective tissue in 3 of 5 patients with adult-onset DM. None of these patients showed positive hybridization to probes derived from human EVs (poliovirus type 1 and Coxsackie virus B3) applied to subjacent sections of the same biopsies. The remaining 2 adult DM patients, 4 patients with childhood-onset DM, and 24 non-DM patients did not react with either TMEV or human enterovirus probes. Histochemical stains for esterase and immunoperoxidase stains for Mac-1 antigen in the 3 DM patients who reacted positively revealed positive cells in the same distribution as, but in far greater number than, those positive by in situ hybridization. Immunoperoxidase staining for HLA-DR antigens revealed positive cells in the same distribution and number as were seen with the TMEV probe. We conclude that an EV-like agent, more closely related to TMEV than to human EVs, may be associated with DM and that this agent is probably localized within muscle macrophages that express class II major histocompatibility complex antigens.

Is there a direct differentiation-inducing effect of human recombinant interferon on hairy cell leukemia in vitro?

We used a panel of monoclonal antibodies (moAb) to label splenic hairy cells from eight patients to determine the membrane phenotypes, the presence of cytoplasmic immunoglobulin (cIg), and the expression of maturation-associated antigens. All eight patients had responded clinically to splenectomy either alone or in combination with alpha-2b-interferon (alpha-IFN) therapy. For each sample, cytofluorimetric analysis showed distinct, and in six cases multiple, heavy chain isotypes. After short-term culture in the presence of alpha-IFN or gamma-interferon (gamma-IFN), samples from four patients displayed characteristic changes in surface immunoglobulin (sIg) expression. When compared with untreated cells, cells co-cultured with alpha-IFN or gamma-IFN showed in four and three patients, respectively, changes that were consistent with a shift to the more mature stage in B-cell ontogeny. However, in parallel with the changes in the sIg isotypes, treatment with IFN did not induce the appearance of cIg nor did the staining patterns for moAb to CD5, CD19, CD20, and CD22 antigens indicate the induction of terminal maturation. These data suggest that hairy cell leukemia (HCL), a neoplasm of "mature" B-cells, is potentially susceptible to maturation stimuli. Based on these findings, it might be of interest to examine whether co-factors, which have proved to play a role in HCL (e.g., B-cell growth factor [BCGF]), are capable of further enhancing IFN-induced differentiation.

Expression of a class I MHC transgene: effects of in vivo alpha/beta-interferon treatment

Transgenic mice containing a swine class I major histocompatibility complex (MHC) gene, PD1, express swine MHC (SLA) antigen. The tissue distribution of PD1 RNA parallels that observed in the swine, indicating that the expression of PD1 is regulated and that trans-acting factors involved in this regulation have been conserved between the species. Although PD1 RNA levels were much greater in transgenic spleen than in thymus, no difference in the chromatin organization of the PD1 gene was detected. In both tissues, a single DNase I hypersensitive site mapped within the 5' flanking region. In vivo treatment of the transgenics with mouse alpha, beta-interferon increases PD1 expression in a number of tissues. In the spleen, this increase parallels that observed for the endogenous transplantation antigen, Kb, but differs markedly from the differentiation antigen, Qa-2. Increases in cell surface expression of both PD1 and Kb occurred equally in splenic T- and B-cell populations following alpha, beta-interferon treatment. In contrast, Qa-2 expression in B cells was enhanced by alpha, beta-interferon, whereas it was unaffected in T cells and thymocytes.

Expression of CD5, a lymphocyte surface antigen on the endothelium of blood vessels

CD5 is a lymphocyte surface antigen considered to be a pan-T cell marker although it is also expressed on a small population of B cells. In this report we present evidence that four different monoclonal antibodies specific for the CD5 antigen also recognize a molecule present on the endothelium of blood vessels in certain regions (placentomes) of the pregnant sheep uterus. The identity of the CD5 antigen on the endothelium with that expressed on T lymphocytes was confirmed by molecular mass analysis of the CD5 antigen in membrane extracts of lymphocytes, thymocytes and placentomes which showed that all three antigens have an apparent molecular mass of 67 kDa. Possible implications of this finding in relation to the function of the CD5 molecule and lymphocyte migration are discussed.

Human lymphocytes bearing T cell receptor gamma/delta are phenotypically diverse and evenly distributed throughout the lymphoid system

A direct quantitative and phenotypic cytofluorographic analysis of TCR-gamma/delta+ lymphocytes as well as an immunohistologic study of their tissue distribution and microanatomy was made possible by the availability of two mAbs (anti-TCR-delta 1 and anti-C gamma M1) specific for framework determinants on human TCR gamma and delta chains, respectively. TCR-gamma/delta+ lymphocytes, ranging between greater than 0.5 and 16% of CD3+ cells, were found in fetal and postnatal thymus, fetal and adult peripheral lymphoid organs, and adult peripheral blood. While TCR-gamma/delta+ lymphocytes comprised a small subpopulation of T cells (mean, approximately 4%) occasionally greater than 10-16% of CD3+ cells expressed TCR-gamma/delta. Virtually all TCR-gamma/delta+ thymocytes/lymphocytes expressed CD7, CD2, and CD5 but were heterogeneous with respect to their expression of CD1, CD4, CD8, CD28, CD11b, CD16, and Leu-7. Human TCR-gamma/delta+ cells populate both organized lymphoid tissues (thymus, tonsil, lymphnode, and spleen) as well as the gut- and skin-associated lymphoid systems at similar frequencies without obvious tropism for epithelial microenvironments. TCR-gamma/delta+ lymphocytes tend to be located within a given organ wherever TCR-alpha/beta+ lymphocytes are found. This study shows that TCR-gamma/delta+ lymphocytes constitute a small but numerically important, phenotypically diverse T cell population distributed throughout the body. These results support the concept that TCR-gamma/delta+ cells comprise a distinct, functionally heterogeneous, mature T cell sublineage that may substantially broaden the T cell repertoire at all immunologically relevant sites.

The reconstitution of cell-mediated immunity in the cutaneous lesions of lepromatous leprosy by recombinant interleukin 2

Human rIL-2 (10-30 micrograms) was injected intradermally into the skin of patients with lepromatous leprosy with high bacillary loads. All patients responded to the lymphokine with local areas of induration that peaked at 24 h and persisted for 4-7 d irrespective of whether the site was "normal skin" or a nodular lesion. Within 24 h there was an extensive emigration of T cells and monocytes into the site. The percentage of the dermis infiltrated by mononuclear cells increased by more than sevenfold, peaking at 4 d and persisting for greater than 15 d. Both CD4+ and CD8+ T cells entered the site. T cells of CD4+ phenotype predominated at 2-7 d but by 11 d, CD8+ cells were predominant. Considerable numbers of T6+ Langerhans' cells appeared in the dermis by 72 h and persisted for 3 wk. By 4 d the thickness of the overlying epidermis had increased twofold, and keratinocytes were expressing MHC class II antigen and the IFN-gamma-induced peptide IP-10. Starting at 48 h, there was an extensive destruction of mononuclear phagocytes that contained structurally intact or fragmented M. leprae observed at the electron microscope level. The organisms, either free or contained within endocytic vacuoles, were discharged into the extracellular space and then reingested by blood-borne monocytes. This was followed by marked reductions in the number of acid-fast organisms in the injected site, evident as early as 4-7 d and more marked at 2-3 wk after injection. 13 of 15 patients exhibited a disposal of acid-fast bacilli ranging from 5- to 1,000-fold with a mean value of approximately 100-fold. The administration of IL-2 leads to the generation of an effective cell-mediated immune response, recapitulating an antigen-driven event and leading to striking local reductions in M. leprae. In comparison with the purified protein derivative of tuberculin reaction, bacilli are cleared more promptly, although emigratory cells persist for a shorter time.

Coexistence of myelodysplastic syndrome and untreated chronic lymphocytic leukemia with development of acute myeloid leukemia immediately after treatment of chronic lymphocytic leukemia

A 72-year-old man originally seen for anemia and thrombocytopenia was determined to have chronic lymphocytic leukemia (CLL). Bone marrow examination at the time of CLL diagnosis revealed a small but significant population of atypical blasts. Cytogenetic analysis of the bone marrow aspirate disclosed chromosomal abnormalities (-7, +8) suggestive of a myelodysplastic syndrome. Shortly after treatment of the CLL, there was proliferation of the previously noted blast population, which cytochemical studies demonstrated to be of the myeloid series thus indicating acute myeloid leukemia superimposed on CLL. This report presents microscopic, cytogenetic, immunophenotypic, and cytochemical evidence to document the evolution of acute myeloid leukemia in the bone marrow of a patient with CLL after one course of chemotherapy.

Tumor-infiltrating lymphocytes and histocompatibility antigens in primary intracranial germinomas

Subpopulations of tumor-infiltrating lymphocytes (TIL's) and the major histocompatibility complex (MHC) antigens of neoplastic cells were examined in three intracranial germinomas by an immunohistochemical method using monoclonal antibodies. About 70% to 80% of TIL's were T lymphocytes which were either infiltrating diffusely or in clusters, whereas 20% to 30% of TIL's were B lymphocytes which tend to cluster in tumor tissues. Examination of T lymphocyte phenotypes revealed both the cytotoxic/suppressor and helper/inducer T lymphocytes, as in other tumors. However, the existence of a considerable number of B lymphocytes in the TIL population was uncommon and seemed to be a characteristic feature of the intracranial germinoma, which might suggest a difference of host immune response to this neoplasm as compared to other tumors. On examination of the MHC antigens, no MHC class I or II antigens in the neoplastic cells were stained, while positive staining for both antigens was seen in the TIL and stroma tissues. From these findings, it was suggested that the degree of TIL infiltration might not be correlated with the expression of MHC antigens in neoplastic cells in cases of primary intracranial germinoma.

Leukocyte types in cerebrospinal fluid and peripheral blood enumerated immunoenzymatically in aseptic meningitis and the Guillain-Barré syndrome

To study celltype distribution simultaneously in peripheral blood (PB) and cerebrospinal fluid (CSF) from patients with aseptic meningitis (AM) (n = 14) and Guillain-Barré syndrome (GBS) (n = 9) we used an immunoenzymatic method that enabled the use of several monoclonal antibodies, also in CSF samples with normal cellcounts. In both patient groups a different cell-distribution in CSF compared to PB was found with regard to pan T cells (CD5+/anti-Leu1+), T cell subpopulations (CD4+/anti-Leu3+, CD8+/anti-Leu2+), B cells (OKB2+, OKB7+), monocytes/macrophages (CD11+/OKM1+) and HLA/DR expressing cells, whereas the distribution of HLA/DC+ cells was similar in CSF and PB. Thus, the CSF cell distribution does not reflect the distribution in PB. The proportion of T cells was higher and the proportion of B-cells was lower in CSF than in PB in both patient groups, which is a finding similar to that in patients with multiple sclerosis. The OKT9 marker, labelling proliferating cells expressing the transferrin receptor, was not useful as marker of local proliferation.

Monoreactive high affinity and polyreactive low affinity rheumatoid factors are produced by CD5+ B cells from patients with rheumatoid arthritis

In patients with rheumatoid arthritis (RA), circulating CD5+ B lymphocytes, but not CD5- B lymphocytes, are increased in number and size, exist in an activated state, spontaneously proliferate, and secrete Ig that binds to the Fc fragment of IgG. By constructing continuous mAb-secreting cell lines from CD5+ B lymphocytes, the properties and dissociation constants (Kd) of these antibodies were determined. Two types of rheumatoid factors (RFs) with discrete reactivities were produced. The first type is polyreactive and binds with relatively low affinity (Kd, 10(-5) mol/liter) to the Fc fragment of IgG. These antibodies are similar to those produced by CD5+ B cells from healthy subjects. The second type of RF is monoreactive and binds with higher affinity (Kd, 10(-7) mol/liter) to the Fc fragment of IgG. These latter autoantibodies are produced by CD5+ B cells of RA patients, but not healthy subjects. Long-term longitudinal studies are needed to determine the role of these two types of RFs in the pathogenesis of RA.

The nature and kinetics of a delayed immune response to purified protein derivative of tuberculin in the skin of lepromatous leprosy patients

We have analyzed the nature and kinetics of a delayed, cell-mediated immune response to a purified protein derivative of tuberculin (PPD) in the skin of 154 naturally sensitized patients with lepromatous leprosy. After the intradermal injection of 5 U of PPD, biopsies were taken at 1-21 d and studied for the composition, extent, persistence, and organization of the emigratory cell response by light and electron microscopy. Induration of positive sites occurred promptly, reached a maximum diameter at 4 d, displayed a major extravasatory element, and was evident for as long as 21 d. The cellularity of the site exhibited a biphasic course, reached a maximum at 7 d, involved as much as 70% of the dermis and millions of new cells, and was elevated threefold above preinjection levels at 21 d. The emigratory cells were limited to T cells and circulating monocytes. T cells were more evident as they entered a preexisting lepromatous lesion containing parasitized macrophages and only occasional T cells many of the CD8+ phenotype. The predominant emigratory T cell was CD4+ although CD8+ cells were in evidence. The CD4/CD8 ratio of the lesions started at less than unity and in two distinct steps reached levels as high as 5:1. In most sites CD4+ cells were in the majority at 21 d. A well-defined granulomatous response with epithelioid and giant cells was apparent at 4 d, reached a maximum at 7 d, and involved all PPD sites at this time point. The generation of these differentiated mononuclear phagocytes from newly emigrated monocytes was never observed in the underlying lepromatous lesion but is a constant feature of the tuberculoid leprosy response. Epidermal thickening and keratinocyte proliferation, sequellae of the dermal reaction, reached a maximum at 7 d and gradually resolved by 3 wk. A constant feature of the PPD response was the extensive destruction of preexisting macrophages containing Mycobacterium leprae bacilli or their products. This was associated with the presence of and intimate contact with highly polarized lymphoid cells of unknown phenotype. Cell destruction did not involve other elements of the dermis and spared parasitized Schwann cells. Newly emigrated T cells and monocytes were never seen within the perineural sheath in contact with neural elements. It appears that a single antigenic stimulus leads to a very long-term, defined series of events with distinct temporal patterns. It includes waves of emigratory T cells, the maturation and organization of monocytes, the generation of killer cells, and the extensive destruction of parasitized macrophages.(ABSTRACT TRUNCATED AT 400 WORDS)