T-cell growth factor receptor (Tac-antigen) expression in cutaneous lymphoid infiltrates

Production and characterization of an active single-chain variable fragment antibody recognizing CD25

The alpha subunit of the interleukin-2 receptor (IL-2Ralpha, CD25) is a potential target in therapeutic approaches for hematolopoietic malignancies expressing CD25 on their cell surface, such as adult T cell leukemia/lymphomas. Recent reports have demonstrated that depletion of CD4+CD25+ regulatory T cells with anti-CD25 antibodies may enhance host tumor immunity. We previously raised a mouse monoclonal antibody (mAb), Ta60b mAb (IgG1kappa), specifically recognizing CD25, and an attempt was made here to produce a single chain Fv fragment (scFv) from this mAb as an initial step to development of scFv-based therapeutics. cDNA fragments encoding for the variable regions of the light and heavy chains of the Ta60b mAb were thus isolated by polymerase chain reaction-mediated cloning, and, an expression vector constructed to express Ta60b scFv fused with the maltose binding protein (MBP) in the periplasm of Escherichia coli. The soluble form of MBP-Ta60b fused scFv could be extracted and affinity-purified with an amylose/agarose column, allowing its immunoreactivity to be analyzed by enzyme-linked immunosorbent assay (ELISA), mixed hemadsorption assay, and fluorescence activated cell sorting. In addition, binding activity was studied by competitive ELISA and surface plasmon resonance. The results showed that Ta60b scFv obtained from periplasm retains good reactivity, although its KD value was 4-fold lower than that of the whole Ta60b antibody, suggesting possible clinical use for treatment of patients with CD25-expressing tumors and also for enhancing anti-tumor immunity.

Phase I trial of recombinant immunotoxin anti-Tac(Fv)-PE38 (LMB-2) in patients with hematologic malignancies

PURPOSE

To evaluate the toxicity, pharmacokinetics, immunogenicity, and antitumor activity of anti-Tac(Fv)-PE38 (LMB-2), an anti-CD25 recombinant immunotoxin that contains an antibody Fv fragment fused to truncated Pseudomonas exotoxin.

PATIENTS AND METHODS

Patients with CD25(+) hematologic malignancies for whom standard and salvage therapies failed were treated with LMB-2 at dose levels that ranged from 2 to 63 microg/kg administered intravenously over 30 minutes on alternate days for three doses (QOD x 3).

RESULTS

LMB-2 was administered to 35 patients for a total of 59 cycles. Dose-limiting toxicity at the 63 microg/kg level was reversible and included transaminase elevations in one patient and diarrhea and cardiomyopathy in another. LMB-2 was well tolerated in nine patients at the maximum-tolerated dose (40 microg/kg QOD x 3); toxicity was transient and most commonly included transaminase elevations (eight patients) and fever (seven patients). Only six of 35 patients developed significant neutralizing antibodies after the first cycle. The median half-life was 4 hours. One hairy cell leukemia (HCL) patient achieved a complete remission, which is ongoing at 20 months. Seven partial responses were observed in cutaneous T-cell lymphoma (one patient), HCL (three patients), chronic lymphocytic leukemia (one patient), Hodgkin's disease (one patient), and adult T-cell leukemia (one patient). Responding patients had 2 to 5 log reductions of circulating malignant cells, improvement in skin lesions, and regression of lymphomatous masses and splenomegaly. All four patients with HCL responded to treatment.

CONCLUSION

LMB-2 has clinical activity in CD25(+) hematologic malignancies and is relatively nonimmunogenic. It is the first recombinant immunotoxin to induce major responses in cancer. LMB-2 and similar agents that target other cancer antigens merit further clinical development.

Fibronectin and lymphocytes in inflammatory tissue. Studies of blood and synovial fluid lymphocytes from patients with rheumatoid arthritis and other inflammatory arthritides

Lymphocytes infiltrating tissues under chronic inflammatory conditions are often surrounded by deposits of fibronectin. We have studied the possibility that this reflects capacity of lymphocytes to synthesize fibronectin and compared lymphocytes from blood and synovial fluid with respect to fibronectin interactions. In vitro activated blood lymphocytes exhibited synthesis of a fibronectin-like molecule. Synovial fluid cells appeared to synthesize the same high molecular weight component spontaneously. Activated blood lymphocytes have cell surface fibronectin and surface components of lower molecular weight which could be immunoprecipitated with anti-fibronectin antibodies as well as by insolubilized collagen. Synovial fluid cells showed cell surface fibronectin as revealed by immunocytochemical detection but seemed to lack or have relatively small amounts of the low-molecular weight fibronectin-like surface components. Synovial fluid T cells from arthritis patients showed adhesion to fibronectin. Immunocytochemistry demonstrated presence of alpha 4 and alpha 5 beta 1 integrins at the surface of the synovial fluid T cells and RGD and LDV peptides inhibited adhesion of the cells to fibronectin. Noteworthy, a portion of synovial fluid cells with lymphocyte markers also bound to plastic. Blood lymphocytes from the same arthritis patients displayed relatively poor or negligible adhesion to fibronectin unless activated to blast transformation and did not attach to plastic. Taken together these results suggest that activated lymphocytes from blood and synovial fluid may use fibronectin of exogenous or endogenous origin when interacting with tissues during inflammatory processes. Furthermore, the presence at the lymphocyte surface of components of different molecular weight precipitated by anti-fibronectin antibodies suggests that fibronectin or its fragments can bind to the lymphocyte surface.

Lymphocyte infiltration of the skin in transgenic mice carrying the human interleukin-2 gene

Inflammatory lesions of the skin such as erythema, depigmentation and hair loss were observed in C57/BL6(B6) transgenic mice that carried an intact human genomic interleukin-2 gene (gIL-2 transgenic mice). Accumulation of T lymphocytes in the perivascular and periadnexal areas of the dermis was the first change, followed by dermal papillary oedema, which occurred before the development of macroscopic skin lesions. In 3- or 4-week-old transgenic mice with slight erythema and depigmentation of the skin, there was an increase in the number of perivascular lymphocytes accompanied by the diffuse infiltration of neutrophils and monocytes in the damaged skin. These morphological skin changes were not observed in non-transgenic mice, which were bred together with transgenic litter mates. These findings suggest that lymphocyte infiltration of the perivascular space of the skin is a primary event of exogenously introduced human interleukin-2 gene, resulting in secondary cutaneous changes in gIL-2 transgenic mice.

Characterization of the dermal infiltrates in Jessner's lymphocytic infiltrate of the skin, polymorphous light eruption and cutaneous lupus erythematosus: differential diagnostic and pathogenetic aspects

In the present study a comparative immunohistochemical study was performed on skin biopsies from of patients with Jessner's lymphocytic infiltration of the skin (LIS), polymorphous light eruption (PLE), discoid lupus erythematosus (DLE) and subacute cutaneous lupus erythematosus (SCLE) using a large panel of monoclonal antibodies against T cell differentiation antigens (CD3, CD4, CD8), immunoregulatory T cell subsets (CD7, 4B4, 2H4, Leu 8), B cells (CD22), activated cells CD25, OKT9, HLA-DR), Langerhans cells (CD1) and macrophages (Leu-M5). The results showed many similarities between LIS and PLE. The most important differences between these conditions and CDLE/SCLE were the high proportions of cells reactive with monoclonal antibody Leu-8 and the absence of T cells expressing HLA-DR antigens in LIS and PLE, suggesting absence of local T cell activation in these conditions. The differential diagnostic and pathogenetic aspects of these findings will be discussed.

Characterization of skin infiltrating cells in adult T-cell leukaemia/lymphoma (ATLL): clinical, histological and immunohistochemical studies on eight cases

Eight cases of adult T-cell leukaemia/lymphoma (ATLL) with cutaneous involvement were studied. The clinical and histological features of these cases were recorded and immunohistochemistry carried out using a panel of monoclonal antibodies to T-cell differentiation antigens. Patients with ATLL showed distinct differences from patients with mycosis fungoides (MF) and Sézary syndrome (SS). Patients tended to have papulonodular and purpuric skin eruptions with pleomorphic lymphoid infiltrates, and often a degree of vasculitis. There was a high level of expression of activated T-cell antigens, CD25, CD30, CD38, T9 and Leu 8.

DNA analysis by flow cytometry in cutaneous T-cell lymphomas

DNA histograms of skin and blood specimens from 64 patients with known or suspected cutaneous T-cell lymphoma (CTCL) have been examined and compared with normal blood mononuclear cells and skin biopsy samples from 50 patients with various benign cutaneous conditions (i.e. patch test infiltrates, eczema, psoriasis, lichen planus, atopic dermatitis) in an attempt to establish whether DNA measurements by flow cytometry may improve the early recognition of CTCL. The results indicate that right-skewed G0/G1 peaks are seen frequently in both benign disorders and known and suspected CTCL. Such peaks may reflect increased stainability of DNA due to chromatin dispersion during cell activation and/or cell proliferation and do not constitute reliable evidence of malignancy. In contrast, discrete aneuploid DNA peaks are confined to malignant lesions, but are seen almost exclusively in the advanced stages in which the diagnosis can be established easily based on routine histological criteria. These data indicate that DNA measurements by flow cytometry is of only limited help in the early recognition of CTCL and support the view that the lymphoid infiltrate in early CTCL may be reactive (rather than neoplastic) or alternatively may contain only minor reactive (rather than neoplastic) or alternatively may contain only minor populations of abnormal (malignant) cells which cannot be detected by currently available DNA measurement techniques.

Expression of a Hodgkin and Reed-Sternberg cell associated antigen (Ki-1) in cutaneous lymphoid infiltrates

Skin biopsy specimens from normal skin and from 115 patients with benign dermatoses, pre- or pseudo-malignant disorders or malignant cutaneous lymphomas have been examined immunohistologically for expression of the Reed-Sternberg cell associated antigen CD30 detected by monoclonal antibodies Ki-1 and Ber-H2. The antibodies stained the atypical cells in lymphomatoid papulosis, a proportion of the neoplastic cells in some cases of mycosis fungoides and most of the neoplastic cells in six large cell anaplastic/pleomorphic non-Hodgkin's lymphomas. The lymphoid cells in all other specimens were Ki-1- and Ber-H2-negative. In all cases, expression of the Ki-1/Ber-H2 antigen was accompanied by expression of activation and proliferation associated markers (i.e., HLA-DR, IL-2 receptor, transferrin receptor and the Ki-67 nuclear antigen). These data indicate the value of antibodies Ki-1 and Ber-H2 in distinguishing between lymphomatoid papulosis and other types of pre- or pseudo-malignant disorders and support the view that lymphomatoid papulosis, Hodgkin's disease and some types of non-Hodgkin's lymphoma constitute a spectrum of related disorders, originated from activated lymphoid cells.