O-sulfated bacterial polysaccharides with low anticoagulant activity inhibit metastasis.

Heparin-like polysaccharides possess the capacity to inhibit cancer cell proliferation, angiogenesis, heparanase-mediated cancer cell invasion, and cancer cell adhesion to vascular endothelia via adhesion receptors, such as selectins. The clinical applicability of the antitumor effect of such polysaccharides, however, is compromised by their anticoagulant activity. We have compared the potential of chemically O-sulfated and N,O-sulfated bacterial polysaccharide (capsular polysaccharide from E.

Safety of blocking vascular adhesion protein-1 in patients with contact dermatitis.

Vascular adhesion protein-1 mediates leukocyte binding to vascular endothelia and migration to tissues. It is upregulated in inflammatory conditions. We studied the safety of vascular adhesion protein-1 blockade by a single dose of the mouse monoclonal antibody vepalimomab in patients with nickel-induced allergic contact dermatitis lesions.

Generation of "neoheparin" from E. coli K5 capsular polysaccharide.

Heparin remains a major drug in prevention of thromboembolic disease. Concerns related to its animal source have prompted search for heparin analogues. The anticoagulant activity of heparin depends on a specific pentasaccharide sequence that binds antithrombin.

Crystallization and preliminary X-ray analysis of the human vascular adhesion protein-1.

Human vascular adhesion protein-1 (VAP-1) is a membrane-bound multifunctional glycoprotein with both adhesive and enzymatic properties. The protein belongs to the copper-containing amine oxidase (CAO) family, which use 2,4,5-trihydroxyphenylalanine quinone as a cofactor. Here, the crystallization and preliminary X-ray analysis of a mammalian CAO, human VAP-1, is reported.

Antibodies to CD44 and integrin alpha4, but not L-selectin, prevent central nervous system inflammation and experimental encephalomyelitis by blocking secondary leukocyte recruitment.

The role of various adhesion molecules in lymphocyte homing to the brain and in inflammatory autoimmune disease of the central nervous system (CNS) was examined in mice. Activated T cell lines and clones expressed CD44 and integrin alpha4, but not L-selectin, and entered the CNS independent of their antigen specificity. mAbs directed against CD44 and integrin alpha4 prevented the transfer of experimental autoimmune encephalomyelitis (EAE) by myelin basic protein-specific T cells.

Treatment of experimental encephalomyelitis with a peptide analogue of myelin basic protein.

Following induction of experimental encephalomyelitis with a T-cell clone, L10C1, that is specific for the myelin basic protein epitope p87-99, the inflammatory infiltrate in the central nervous system contains a diverse collection of T cells with heterogeneous receptors. We show here that when clone L10C1 is tolerized in vivo with an analogue of p87-99, established paralysis is reversed, inflammatory infiltrates regress, and the heterogeneous T-cell infiltrate disappears from the brain, with only the T-cell clones that incited disease remaining in the original lesions. We found that antibody raised against interleukin-4 reversed the tolerance induced by the altered peptide ligand.

Infection and multiple sclerosis: a possible role for superantigens?

The association of infection with autoimmune diseases is enigmatic, partly because cause and effect are difficult to establish in chronic diseases. Microorganisms might initiate multiple sclerosis and trigger relapses of disease. Superantigens might be involved in autoimmunity through the (re)activation of T cells, including autoreactive cells, expressing certain T cell receptor beta chain variable regions.

Inhibition of meiotic divisions of rat spermatocytes in vitro by polycyclic aromatic hydrocarbons.

The toxic effects of polycyclic aromatic hydrocarbons (PAH) on spermatogenic cells undergoing meiotic division were investigated in vitro. Toxicity was assayed as alterations in cell nucleus morphology and cell survival and by DNA flow cytometry. Benzo[a]pyrene (BP) and 7,12-dimethylbenz[a]anthracene (DMBA) inhibited the progression of spermatocytes through meiotic division and were highly cytotoxic at concentrations higher than 1 microM.

TCDD inhibits the support of B-cell development by the bursa of Fabricius.

The toxic effects produced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and its congeners include inhibition of lymphoid development. We have previously found an inhibition of B-cell development in the bursa of Fabricius of chick embryos treated with TCDD congeners in ovo. In the present study, the bursae of ten-day-old chick embryos were removed and cultured on filter paper for 24 hr in media with or without TCDD or 3,3',4,4'-tetrachlorazoxybenzene (TCAOB).

DNA-flow cytometry of defined stages of rat seminiferous epithelium: effects of 3 Gy of high-energy X-irradiation.

Testes of adult Sprague-Dawley rats were irradiated locally by 3 Gy of 4 MeV X-rays produced by a linear accelerator. This type and dose of radiation gives an even distribution through the testis and selectively kills the proliferating spermatogonia. The seminiferous tubular cells were quantified by DNA flow cytometry at defined stages of the epithelial cycle at 7, 17, 22, 38, 52, and 80 days after irradiation.

B cell-induced tolerance to class II MHC antigens in the chicken.

Transplantation of cells from the bursa of Fabricius reconstitutes the B cell system of chemically bursectomized chickens. Even allogeneic bursa cells can restore the recipient's B cell system and induce tolerance to donor major histocompatibility complex antigens, but the chimeras cannot mount a T-dependent antibody response. In order to study the mechanisms of tolerance to class II MHC (B-L) antigens, we transplanted class II-incompatible bursa cells from 4-day-old donors into cyclophosphamide-treated recipients of the same age.

B cell maturation in the chicken Harderian gland.

We have characterized maturation of B lymphocytes in the chicken Harderian gland. Expression of Ig genes was studied by using lambda L and mu H chain-specific DNA probes. In unstimulated chickens, the concentration of mu H chain and lambda L chain mRNA in the Harderian gland was observed to be greater than 8 times higher than in the bursa of Fabricius or spleen.

B-cell differentiation in the chicken: expression of immunoglobulin genes in the bursal and peripheral lymphocytes.

We have studied the expression of immunoglobulin genes in the chicken B-cell precursors, and of a B-cell surface marker (Bu-1) on the bursal and peripheral B cells during normal ontogeny. Since there is no way of distinguishing the precursor cells from the more mature bursal lymphocytes on the basis of surface markers, we chose to study the total bursal lymphocyte population at ages when the numbers of the various precursor cells (bursal, early post-bursal, and post-bursal stem cells) in the bursa are estimated to be at their highest. Thereafter, comparisons with the more mature lymphocytes in the peripheral organs were made.

Tolerance to class I major histocompatibility complex antigens in chicken B cell chimeras. Effect of B cell depletion on transferability of tolerance.

B cells from bursa of Fabricius of newly hatched chickens are able to reconstitute the B cell compartment of chemically bursectomized chickens. The resulting B cell chimerism can be detected with monoclonal antibodies against donor B cell alloantigen. Chimeric chickens accept donor-type skin grafts and are unresponsive to donor major histocompatibility complex (MHC) antigens in graft-vs.

Antigen-presenting cell-T cell interaction in the chicken is MHC class II antigen restricted.

The involvement of the MHC in the recognition of Ag by avian T lymphocytes was analyzed. PBL from chickens primed with keyhole limpet hemocyanin in vivo were induced to synthesize DNA in an in vitro response to specific Ag. Responding cells were T cells as judged by immunofluorescence staining.

Expression of B-L and Bu-1 antigens in chickens bursectomized at 60 h of incubation.

Differences in expression between B-L (chicken class II major histocompatibility complex antigen) and Bu-1 B cell antigens were found in normal animals by using monoclonal antibodies and flow cytometric immunofluorescence analysis. Fluorescence intensity profile was used in assaying cell surface density of antigen molecules. The density of B-L antigen on the cell surface is apparently low in immature and high in mature cells, whereas the density of Bu-1 antigen does not vary in cells at different maturational stages.

Monoclonal antibodies against chicken Bu-1a and Bu-1b alloantigens.

The production and characterization of monoclonal antibodies (mAbs) against chicken B cell surface alloantigens, Bu-1a and Bu-1b, is described. Flow cytometric analysis using these mAbs demonstrates that Bu-1 gene locus does not show allelic exclusion. Two color fluorescence analysis using simultaneous surface marker labeling and DNA staining shows that the expression of Bu-1 antigen is not restricted to a specific phase of the cell cycle.

Effect of cytosine arabinoside on the human immunosystem: metabolism and cytotoxicity studied with mitogen-stimulated normal blood lymphocytes in vitro.

The toxicity, metabolic effects and metabolism of cytosine arabinoside (Ara-C) were studied with normal human peripheral blood PHA-stimulated mononuclear cells in vitro. Clinically relevant Ara-C concentrations were toxic against mitogen-stimulated blood lymphocytes. Dose-dependent effects included: (i) increased cell loss, (ii) decreased DNA synthesis assessed by 3H-thymidine incorporation, (iii) decreased blastic transformation, (iv) decreased protein synthesis assessed by 14C-leucine incorporation, (v) an inhibition of the production of new cells, (vi) a delay in the proceeding of the PHA-stimulated cells to the cell cycle, (vii) an arresting of the cells in the S-phase, and (viii), a dose-dependent decrease of the number of mitoses in Ara-C-treated cultures.

Granulocyte-specific monoclonal antibody inhibiting cytotoxicity reactions in the chicken.

Monoclonal antibody (MAb) 1C3, specific for chicken granulocytes, is described for the first time. Treatment of peripheral blood leukocytes with this MAb markedly decreased natural cytotoxicity reaction against the target cell line. The antibody-dependent cellular cytotoxicity (ADCC) activity of purified granulocytes was also severely affected by treatment with MAb 1C3.

T cell function in chickens bursectomized at 60 hours of incubation.

Chickens surgically bursectomized in ovo (Bx) at 60 hr of embryonic development offer a unique model to study selectively the influence of the bursa of Fabricius on thymus-dependent immune functions because the lymphoid cells of these animals develop in the total absence of the bursal microenvironment. The Bx chickens have been shown to be unable to respond to antigenic stimulation by specific antibody production. In the present study, we have characterized different aspects of T-cell-mediated immunity in Bx chickens.

Effect of cytosine arabinoside on the human immunosystem: toxicity against quiescent human peripheral blood mononuclear cells in vitro.

The toxic and metabolic effects of cytosine arabinoside (Ara-C) were studied in vitro with normal human peripheral blood mononuclear cells. The majority of target cells were T-lymphocytes. Dose-dependent toxicity of clinically relevant Ara-C concentrations was manifested by increased cell loss, inhibition of spontaneous blastic transformation, inhibition of DNA synthesis assessed by 3H-thymidine incorporation, inhibition of protein synthesis assessed by 14C-leucine incorporation, and inhibition of the mitogenic response of T-lymphocytes when challenged with phytohemagglutinin after Ara-C treatment.