The role of dipeptidyl peptidase IV in human T lymphocyte activation. Inhibitors and antibodies against dipeptidyl peptidase IV suppress lymphocyte proliferation and immunoglobulin synthesis in vitro

Dipeptidyl peptidase IV (DP IV), an ectoenzyme in the cell membrane of T lymphocytes, is an important constituent in the process of lymphocyte activation. This conclusion is drawn from the following observations: (a) Proliferation of peripheral blood lymphocytes induced by mitogenic lectins (phytohemagglutinin, concanavalin A, pokeweed mitogen) is suppressed in the presence of DP IV inhibitors. This effect is specific and applies to an irreversible suicide inhibitor as well as to a competitive one in a dose-dependent fashion. (b) Inhibition of DNA synthesis was also induced by a polyclonal anti-DP IV immunoglobulin. (c) As a consequence of impaired T cell function the production of immunoglobulins by pokeweed mitogen-stimulated lymphocytes is also markedly reduced in the presence of DP IV inhibitors.

The high efficiency, human B cell immortalizing heteromyeloma CB-F7. Production of human monoclonal antibodies to human immunodeficiency virus

This paper describes the construction of a new heteromyeloma cell line designated CB-F7. The cell line was derived from xenogeneic somatic cell hybridization between normal human B lymphocytes and the murine HAT-sensitive P3X63Ag8/653 cell line. CB-F7 cells were characterized by rapid cell growth (doubling time about 16 h) and high cloning efficiencies in culture medium supplemented with 10% or 5% fetal calf serum, respectively. The karyotype of the cells consists of about 75-78 chromosomes as well as two chromosomal fragments. Fusions of the cells with human peripheral blood cells resulted in approximately 2-6 clones per 10(5) seeded lymphocytes. Furthermore, the cells are ouabain resistant and therefore suitable for fusions with EBV-transformed lymphoblastoid cell lines. Using CB-F7 as the parental cell line a number of specific human mAb producing hybrids were established. For the first time, we describe here the generation of hybrids secreting human monoclonal antibodies to human immunodeficiency virus (HIV). Two monoclonal antibodies of IgG type and one of IgM type reacted with the major core protein p25 and one IgG antibody reacted with the transmembrane protein gp41.

Evaluation of the 'GeneDisc' real-time PCR system for detection of enterohaemorrhagic Escherichia coli (EHEC) O26, O103, O111, O145 and O157 strains according to their virulence markers and their O- and H-antigen-associated genes

AIMS

To evaluate the GeneDisc multiplex real-time PCR assay for detection of enterohaemorrhagic Escherichia coli (EHEC) O26, O103, O111, O145 and O157 strains.

METHODS AND RESULTS

GeneDiscs for detection of genes encoding Shiga toxins (stx), intimins (eae), E. coli O157 (rfbE(O157)) and H7 (fliC(H7)) antigens as well as genes specific for EHEC O26 (wzx(O26)), O103 (wzx(O103)), O111 (wbd1(O111)), O145 (ihp1(O145)) and O157 (ihp1(O157)) were evaluated. The assay was run with native bacteria in 1 h in a GeneDisc Cycler. All genotypes of stx and eae, except stx(2f) and eae-rho, were identified. Escherichia coli strains belonging to O-groups O26, O103, O111, O157 as well as EHEC O145:[H28] strains were specifically detected with this assay. The ihp1(O157) gene was not found specific for EHEC O157. O-rough mutants of EHEC and non-motile EHEC O157 strains were reliably identified with the GeneDisc assay. Two to three colonies of EHEC strains were still detectable in a lawn of 50 000 apathogenic E. coli from agar plates.

CONCLUSIONS

The GeneDisc assay is a specific and reliable assay for detection of major EHEC strains. It is robust enough to detect few EHEC colonies in mixed cultures of bacteria.

SIGNIFICANCE AND IMPACT OF THE STUDY

The assay is promising for its use in EHEC diagnostics and for EHEC monitoring with different kinds of samples.

IgG human monoclonal anti-DNA autoantibodies from patients with systemic lupus erythematosus

We describe the production of six mouse-human heterohybridomas secreting human IgG anti-dsDNA antibodies derived from patients with systemic lupus erythematosus (SLE). Peripheral blood cells used for fusion experiments were from patients who were shown to have high numbers of anti-DNA secreting B cells in the peripheral blood. All monoclonal antibodies bind to dsDNA in ELISA systems, five are reactive with Crithidia lucilae kinetoplasts and three precipitate dsDNA in the Farr assay. Inhibition studies revealed a remarkable specificity for certain polynucleotide structures. To our knowledge these are the first hybridomas described in the human system that secrete anti-dsDNA antibodies of the IgG class.

Analysis of V(H)-D-J(H) gene transcripts in B cells infiltrating the salivary glands and lymph node tissues of patients with Sjögren's syndrome

OBJECTIVE

In patients with Sjögren's syndrome (SS), B lymphocytes have been found to infiltrate salivary glands, resulting in sialadenitis and keratoconjunctivitis. The disease is frequently associated with benign and neoplastic lymphoproliferation. The present study was undertaken to investigate whether clonal B cell expansion takes place in lymphocytic infiltrations of salivary glands under (auto- [?]) antigen stimulation, by analyzing in more detail the variable part (V(H)-D-J(H)) of the immunoglobulin heavy chain genes expressed in these B cells.

METHODS

Biopsies of the labial salivary glands and lymph nodes were performed on 2 female patients with SS. The Ig gene rearrangements in these tissues were amplified by reverse transcriptase-polymerase chain reaction using specific primers.

RESULTS

A total of 94 V(H)-D-J(H) transcripts were cloned and sequenced. Our data suggest a polyclonal origin of the B cell infiltrates. In 92 of the transcripts, V(H) genes were modified by somatic mutation. Further analysis showed counterselection for replacement mutations within the framework regions, suggesting that those B cells were stimulated and selected for functional expression of a surface Ig. In labial salivary glands from both patients, clonally related B cells became evident. Members of 1 particular clone were found in both the lip and lymph node material.

CONCLUSION

These data provide evidence, on the nucleotide sequence level, that an antigen-triggered clonal B cell expansion takes place in the salivary glands of patients with SS who do not have histologic evidence of developing lymphoma. It may be speculated that those B cell clones expand during disease progression, resulting in lymphomagenesis.

Enhanced expression of T-cell activation and natural killer cell antigens indicates systemic anti-tumor response in early primary cutaneous T-cell lymphoma

Indolent, primary cutaneous T-cell lymphomas (CTCL) are characterized by hyper-proliferation of malignant T-helper cells in the skin with a favorable prognosis in the early stages. Cytotoxic T cells (CTLs) are believed to be of major importance for tumor surveillance, but there is not yet sufficient evidence for a systemic anti-tumor response in mycosis fungoides (MF). On the contrary, there are hints of systemic immunodepression. We wondered whether signs of a systemic anti-tumor response were demonstrable in peripheral blood of patients with MF and CD30+ pleomorphic T cell lymphoma. Using multiparameter flow cytometry, we investigated blood samples from 39 CTCL patients at different stages and compared them with those from patients with psoriasis, atopic dermatitis, and healthy volunteers. In CTCL patients, an elevated number of lymphocytes expressing natural killer cell markers were found, as well as considerable T-cell activation, indicated by increased percentages of T cells expressing HLA-DR, IL-2 receptor alpha-chain, and transferrin receptor. The CD8+ T cells, which were the most strongly activated T-cell subset, were of polyclonal origin, as shown by their usage of different T-cell receptor families. The enhanced expression of activation antigens was associated with an increased proportion of CD8+ T cells with high expression of the adhesion molecule LFA-1, demonstrating the capacity for migration of these cells. These CD8+ effector cells are suspected to be CTLs and may be responsible for the favorable prognosis of indolent, primary CTCL. Interestingly, a stage-dependent decrease in T-cell activation antigen expression was observed, suggesting the development of a lack in tumor surveillance in advanced MF stages. Further investigations are necessary to verify whether any of the parameters determined are of predictive value for prognosis and response to therapy in CTCL.

Primary cutaneous follicle center cell lymphomas and large B cell lymphomas of the leg descend from germinal center cells. A single cell polymerase chain reaction analysis

Primary cutaneous B cell lymphomas are defined as non-Hodgkin lymphomas that occur in the skin without extracutaneous involvement for 6 mo after diagnosis. They are characterized by a less aggressive course and better prognosis than their nodal counterparts. According to the European Organization for Research and Treatment of Cancer classification, the major subentities of primary cutaneous B cell lymphoma are follicle center cell lymphomas, immunocytomas, and large B cell lymphomas of the leg, which differ considerably regarding their clinical behavior, the former two being indolent, the latter being of intermediate malignancy. In this study, we applied a single cell polymerase chain reaction approach to analyze immunoglobulin V(H)/V(L) genes in 532 individual B lymphocytes from histologic sections of four follicle center cell lymphomas localized on the head and trunk, and four large B cell lymphomas on the leg. We found: (i) in six of eight patients a clonal heavy chain, and in seven of eight patients a clonal light chain rearrangement, all being potentially productive; (ii) no bias in VH gene usage, in four of seven light chain rearrangements the V kappa germline gene IGVK3-20*1 was used; (iii) no biallelic rearrangements; (iv) all V(H)/V(L) genes are extensively mutated (mutation rate 5.4-16.3%); (v) intraclonal diversity in six of eight cases (three of each group); and (vi) low replacement vs silent mutation ratios in framework regions indicating preservation of antigen-receptor structure, as in normal B cells selected for antibody expression. Our data indicate a germinal center cell origin of primary cutaneous follicle center cell lymphomas and large B cell lymphomas independent of those belonging to one of these subentities.

Microanatomical compartments of clonal and reactive T cells in mycosis fungoides: molecular demonstration by single cell polymerase chain reaction of T cell receptor gene rearrangements

Mycosis fungoides (MF) is a cutaneous T cell lymphoma, clinically characterized by patches, plaques and tumors occurring in successive stages of the disease. In early MF, an infiltrate consisting of mainly reactive T cells is seen in the papillary dermis while tumor cells are mostly confined to the epidermis. By contrast, later stages show nodular infiltrates formed mostly of tumor cells in the dermis while the epidermis is relatively devoid of tumor cells; however, knowledge of the localization of clonal T cells has been based on histomorphologic features and immunohistochemical stainings visualizing certain V-beta subfamilies of the T cell receptor (TCR). As these techniques do not allow for an unequivocal identification of clonal tumor cells, we used micromanipulation and single cell PCR amplifying the TCR chain gene rearrangement. A total number of 387 single T cells was isolated from six skin biopsies in five patients in patch, plaque, and tumor stages. Of these, 180 T cells were picked from the epidermis and 207 from the dermal infiltrate. The rearranged TCR-gamma DNA could be sequenced from 181 of 387 T cells. In three of six patients representing all three stages, epidermal T cells with a clonal rearrangement could be amplified. In early plaque stage a higher degree of epidermal T lymphocytes was found than in initial patch, later plaque, and tumor stages with an inverse distribution found for reactive T lymphocytes. In two patients a biallelic rearrangement was demonstrated that had not been detected in prior PCR analysis from blood and skin samples. These data show that clonal (neoplastic) and non-clonal (reactive) T lymphocytes in MF preferentially infiltrate different microanatomical compartments of the skin, depending on the stage of disease. The microanatomically distinct localization of reactive and clonal T cells suggests that the absence of direct contact between tumor and host-defense lymphocytes may contribute to tumor persistence and progression in epidermis, peripheral blood, and deep dermal tumor cell nests, respectively.

Correlation between the phenotype and the functional capacity of activated T cells in patients with active systemic lupus erythematosus

Activated T cells in the peripheral blood of patients with systemic lupus erythematosus (SLE) were determined using monoclonal antibodies against activation antigens. Elevated percentages of HLA-DR+ T cells were found in association with active disease. In contrast, we observed an increase in IL-2 receptor-bearing T cells in only six out of 16 patients with active disease. In vitro assays, like spontaneous proliferation, response to IL-2, production of IL-2, and immunoglobulin synthesis have shown that the different patterns of activation antigens are related to different functional stages of T-cell activation. The possible therapeutic consequences are discussed.

Immune restoration in children after partial splenectomy

Splenectomy (SE) is recognized to be a therapeutical approach in treating children with severe autoimmune diseases (chronic idiopathic thrombocytopenia; hemolytic anemia) or hypersplenism because of portal hypertension. Nevertheless, removal of a main immune organ results in elevated infection risk for these patients. Partial splenectomy (PSE) was developed as a therapeutical compromise to retain immunologically active spleen tissue. Here, we document the analysis of immune parameters obtained from children after both partial and total splenectomy, which have been followed up for a period of more than 6 years: (i) Lymphocytes from both groups of patients failed to produce IgG in response to pokeweed mitogen in vitro. This was observed in 11/20 splenectomized patients even 10 years after operation, whereas in PSE patients a restoration of this parameter after 1-2 years was seen. (ii) In patients after PSE, but not in splenectomized persons, an elevated number of HLA-class II positive cells had been detected suggesting a different situation of immune regulation following this operation. However, in parallel with an improvement of B cell in vitro activity this parameter was found to achieve normal values. Our findings indicate that partial splenectomy may be a therapeutical alternative, if the therapeutic goal can be achieved by this procedure.

Purification and immunochemical characterization of a natural human polyreactive monoclonal IgM antibody

In vitro and in vivo experiments to explain the function of natural polyreactive antibodies, usually of the IgM isotype, require large amounts of purified antibodies. We have developed a two-step purification procedure using a human natural polyreactive monoclonal IgM antibody (CB03). This combines hydrophobic interaction chromatography on phenyl-Superose and gel filtration over Superose 12 and readily permits scaling-up to isolate mg to g amounts of antibody. Retention of the CB03 antibody during gel filtration by precipitation and interaction with the gel matrix was overcome by the addition of 10 mM 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate. The yield of purified antibody was 34% and Fab fragments were obtained from the purified CB03 antibody by hot tryptic digestion (yield, 68% of theoretical amount). In an enzyme-linked immunosorbent assay, Fab and complete antibody had similar reaction patterns with different antigens.

The influence of haematoporphyrin derivative and visible light on murine skin graft survival, epidermal Langerhans cells and stimulation of the allogeneic mixed leucocyte reaction

The influence of combined photochemical treatment with a haematoporphyrin derivative and visible light on antigen-presenting cells was evaluated. Treatment of murine skin grafts with this procedure prolonged their subsequent survival on allogeneic recipients. The haematoporphyrin derivative and light decreased the ATPase activity of epidermal Langerhans cells in murine skin. When stimulator cells in a human allogeneic mixed leucocyte reaction were treated with the haematoporphyrin derivative and light, they lost their stimulatory capacity. It is proposed that the haematoporphyrin derivative and visible light interfere, on analogy with ultraviolet radiation, with the function of antigen-presenting cells.

Real-time biospecific interaction analysis of a natural human polyreactive monoclonal IgM antibody and its Fab and scFv fragments with several antigens

Surface plasmon resonance (SPR) was used to investigate the kinetics of interactions between the human monoclonal polyreactive IgM antibody CB03, its Fab as well as its single-chain variable fragment (scFv) and different antigens. From these experiments apparent binding constants were determined and compared with binding constants obtained by ELISA experiments. In SPR studies with the complete antibody, the polyreactivity of the CB03 antibody as derived from ELISA experiments was confirmed. Interaction of scFv with kappa casein and human myoglobin is strong evidence for the location of polyreactivity within the variable domains of the antibody. Apparent binding constants of the complete antibody to immobilized kappa casein (9.2 x 10(7) M-1) and to human myoglobin (1.6 x 10(7) M-1) are up to 83 times higher than those of Fab. The binding constants of the scFv to the above mentioned antigens are again about 10 times lower when compared with Fab, which is mainly due to the lower association rates of the complexes formed by the scFv.

Establishment of human Ig producing heterohybridomas by fusion of mouse myeloma cells with human lymphocytes derived from peripheral blood, bone marrow, spleen, lymph node, and synovial fluid. Effect of polyclonal prestimulation and cryopreservation

50 fusion experiments were carried out to analyse heterohybridization efficiencies on mouse myeloma cells of the P3 X63 Ag8/653 line with human lymphocytes derived from peripheral blood, bone marrow, lymph node, spleen or synovial fluid. We found higher yields of growing and human Ig-producing hybridoma lines when lymphocytes from spleen or lymph node were fused. Although primary hybridomas could be established from fusions with bone marrow-derived cells, only in nine out of 1616 initially seeded wells was Ig production registered. Four fusions using immune cells from synovial fluid were made without success. Independently of the source of lymphocytes pokeweed mitogen (PWM) prestimulation had no enhancing effect on the percentage of wells with cell growth and this did not alter the IgM:IgG ratio in primary hybridomas (9:1), although cells from all compartments used here (with the exception of bone marrow cells) could be stimulated with PWM to produce both IgG and IgM in cultures. Cryopreserved lymphocytes from different sources could be used for fusions with comparable results registered for the fresh material.

Molecular analysis of the immunoglobulin VH gene rearrangement in a primary cutaneous immunoblastic B-cell lymphoma by micromanipulation and single-cell PCR

The immunoglobulin VH gene rearrangement in a primary cutaneous, large-cell (centroblastic and immunoblastic) B-cell lymphoma was analyzed using a micromanipulation/single-cell polymerase chain reaction technique. In all single B cells obtained from CD20-stained skin sections that gave a polymerase chain reaction product (eight of 27 in biopsy I), the same VHDJH rearrangement, consisting of DP-54-DIR1-JH3a genes, was detected, with no intraclonal nucleotide diversity. Comparison with the most closely related germline counterpart showed significantly altered complementarity determining gene regions as a result of somatic mutations, suggesting an antigen-driven selection and expansion ofthis particular B-cell clone. Interestingly, in a biopsy obtained from the patient 9 mo later, during disease progression (deep muscle infiltration), the lymphoma cells again contained the same VHDJH gene rearrangement (six of 18 in biopsy II) without any further somatic mutations. Therefore, it is suggested that the cutaneous lymphoma characterized throughout this study descended from postgerminal center B-cells.

Rationale, design, and methods of a non-interventional study to establish safety, effectiveness, quality of life, cognition, health-related and work capacity data on Alemtuzumab in multiple sclerosis patients in Germany (TREAT-MS)

BACKGROUND

Alemtuzumab, a humanized monoclonal antibody directed against the cell surface glycoprotein CD52, is licensed in Europe since October 2013 as treatment for adult patients with active relapsing-remitting multiple sclerosis (RRMS). In three randomized, rater-blinded active comparator clinical trials studies, alemtuzumab administered in two annual courses, had superior efficacy as compared to subcutaneous interferon beta-1a, and durable efficacy over 5 years in an extension study with a manageable safety profile in RRMS patients. Data on the utilization and the outcomes of alemtuzumab under clinical practice conditions are limited.

METHODS

Here we describe the rationale, design and methods of the TREAT-MS study (non-interventional long-Term study foR obsErvAtion of Treatment with alemtuzumab in active relapsing-remitting MS).

DISCUSSION

TREAT-MS is a prospective, multicenter, non-interventional, long-term study to collect data on safety, effectiveness, quality of life, cognition and other aspects from 3200 RRMS patients treated with alemtuzumab under the conditions of real-world clinical practice in Germany.

TRIAL REGISTRATION

As non-interventional trial in Germany.

Probing DNA with micro- and nanocapillaries and optical tweezers

We combine for the first time optical tweezer experiments with the resistive pulse technique based on capillaries. Quartz glass capillaries are pulled into a conical shape with tip diameters as small as 27 nm. Here, we discuss the translocation of λ-phage DNA which is driven by an electrophoretic force through the nanocapillary. The resulting change in ionic current indicates the folding state of single λ-phage DNA molecules. Our flow cell design allows for the straightforward incorporation of optical tweezers. We show that a DNA molecule attached to an optically trapped colloid is pulled into a capillary by electrophoretic forces. The detected electrophoretic force is in good agreement with measurements in solid-state nanopores.

VH genes expressed in peripheral blood IgE-producing B cells from patients with atopic dermatitis

In this study we analysed the VH genes expressed in IgE-producing peripheral B cells in two patients with severe atopic dermatitis. We found a diverse antibody repertoire containing V(H) genes of five different VH families, no VH2 and 7 genes, with no biased usage of one particular VH gene family. Some VH germ-line segments were found to be used several times within the epsilon transcripts (V3-23, V3-30). Comparison of the IgE-encoding VH genes with the respective germ-line elements revealed the expression of nearly germ-line identical as well as somatically mutated VH genes. In these latter VH genes base substitutions were distributed over both complementarity determining and framework regions. Because of the similarities between the IgE committed B cell repertoire in atopic patients and the peripheral B cell repertoire in non-atopic individuals we conclude that the atopic VH gene repertoire probably reflects the result of an increased class switch of polyclonal B cells, including virgin and mature B cells, in response to a Th2 cytokine profile.

The influence of EDTMP-concentration on the biodistribution of radio-lanthanides and 225-Ac in tumor-bearing mice. The ISOLDE Collaboration

High-resolution gamma spectroscopy was applied to measure simultaneously the biodistribution of carrier-free radionuclides of several lanthanides (141Ce, 145Sm, 149Gd, 167Tm) and 225Ac in tumor-bearing nude mice. Mixtures of the radiotracers were injected in solutions containing different concentrations of EDTMP (ethylenediaminetetramethylenephosphonic acid). The strong dependence of liver uptake on the ionic radius of the radio-lanthanides was confirmed for all tracers used. The ratios of radioactivity concentrated in tumour that concentrated in liver are strongly influenced by the EDTMP concentration, reaching values close to 10 for Tm, 3 for Sm, and 1 for Ac. The optimal EDTMP concentrations, giving highest tumor-to-liver ratios of enrichment, were between 1 and 10 mM for 100 microL injected volume for the animal model used in this experiment. In radionuclide therapy using EDTMP as ligands, close control of ligand concentration will be necessary.

A comparison of human and murine monoclonal IgGs specific for the P1.7 PorA protein of Neisseria meningitidis

Monoclonal human IgG SS269 reacts with Neisseria meningitidis expressing the P1.7 PorA protein and with linear peptides containing NGGAS, which accounts for the P1.7 specificity. Murine monoclonal antibody to P1.7 reacts with peptides containing the overlapping epitope, ASGQ. The human and murine antibodies have similar affinities. The low avidity human antibody is very inefficient at stimulating complement-mediated bactericidal killing while the high avidity murine antibody efficiently kills bacteria. However, efficient opsonophagocytosis was mediated even at low concentrations of the human antibody and in the absence of complement, suggesting that low avidity antibodies might be protective against disease.