Cellular, serological, and molecular polymorphism of the class I and class II loci of the canine Major Histocompatibility Complex.

This study was undertaken to determine the relationships between canine cellular and serological determinants and more recently described genes. Such relationships might reveal information about immunological reactivity or function of various proteins. To do this we studied the haplotypic associations of dog leukocyte antigen (DLA) class I and class II alleles determined from a panel of 14 DLA-D homozygous dogs.

Regulatory effects of novel neurotrophin-1/b cell-stimulating factor-3 (cardiotrophin-like cytokine) on B cell function.

We describe regulatory effects that a novel neurotrophin-1/B cell-stimulating factor-3 (NNT-1/BSF-3; also reported as cardiotrophin-like cytokine) has on B cell function. NNT-1/BSF-3 stimulates B cell proliferation and Ig production in vitro. NNT-1/BSF-3-transgenic mice, engineered to express NNT-1/BSF-3 in the liver under control of the apolipoprotein E promoter, show B cell hyperplasia with particular expansion of the mature follicular B cell subset in the spleen and the prominent presence of plasma cells.

A novel Notch ligand, Dll4, induces T-cell leukemia/lymphoma when overexpressed in mice by retroviral-mediated gene transfer.

Notch receptors mediate cell-fate decisions through interaction with specific ligands during development. The biological role of a novel Notch ligand, Dll4, in mice was explored by reconstituting lethally irradiated mice with bone marrow (BM) cells transduced with Dll4 retroviral vector. White blood cell and lymphocyte counts in Dll4-overexpressing mice were reduced at the early stage of reconstitution but increased significantly at approximately 10 weeks after BM transplantation.

T-cell co-stimulation through B7RP-1 and ICOS.

T-cell activation requires co-stimulation through receptors such as CD28 and antigen-specific signalling through the T-cell antigen receptor. Here we describe a new murine costimulatory receptor-ligand pair. The receptor, which is related to CD28 and is the homologue of the human protein ICOS, is expressed on activated T cells and resting memory T cells.

Novel neurotrophin-1/B cell-stimulating factor-3: a cytokine of the IL-6 family.

We have identified a cytokine of the IL-6 family and named it novel neurotrophin-1/B cell-stimulating factor-3 (NNT-1/BSF-3). NNT-1/BSF-3 cDNA was cloned from activated Jurkat human T cell lymphoma cells. Its sequence predicts a 225-aa protein with a 27-aa signal peptide, a molecular mass of 22 kDa in mature form, and the highest homology to cardiotrophin-1 and ciliary neurotrophic factor.

Passage of leptin across the blood-testis barrier.

Leptin is a 17-kDa protein, secreted by fat, that controls adiposity and has been proposed to have numerous effects on reproduction in the mouse. To assess whether the effects of leptin on testicular function are direct, we determined whether leptin can cross the murine blood-testis barrier. Multiple time regression analysis showed that a small amount of blood-borne leptin is able to enter the testis but does so by a nonsaturable process.

Morphologic and molecular changes induced by recombinant human leptin in the white and brown adipose tissues of C57BL/6 mice.

Leptin is a 16-kd protein synthesized and secreted by adipose tissue, which regulates adiposity and body weight. To investigate the peripheral effects of recombinant human leptin, lean C57BL/6 mice were treated with subcutaneous injections of vehicle or 20 mg/kg/day leptin for 1 to 14 days. Groups of animals were killed on Days 1, 2, 3, 4, 7, or 8 and 15 to evaluate the time course of clinical chemistry, morphologic, and molecular changes in white (WAT) and brown adipose tissue (BAT) depots.

IL-12-deficient mice are defective but not devoid of type 1 cytokine responses.

Interleukin-12 (IL-12) has been described as a pivotal molecule in the immune response based in part on its ability to influence the differentiation of T helper (Th) cells into a type 1 (Th1) phenotype. This event is crucial in that appropriate differentiation of naive T cells can determine susceptibility or resistance to given pathogens by influencing the balance between cellular and humoral immunity. In order to further delineate the role of IL-12 in the immune response, we generated mice deficient for this cytokine.

IL-12-deficient mice are defective in IFN gamma production and type 1 cytokine responses.

IL-12 is a cytokine that can exert regulatory effects on T and NK cells and promote Th1 responses. To delineate further the physiologic role of IL-12 in immunity, mice deficient for this cytokine were generated. IL-12-deficient mice were impaired but not completely lacking in the ability to produce IFN gamma following endotoxin administration and to mount a Th1 response in vivo, as measured by antigen-induced IFN gamma secretion by immune lymph node cells in vitro.

Biologic effects of recombinant human interleukin-12 in squirrel monkeys (Sciureus saimiri).

Background: Interleukin-12 is a novel heterodimeric cytokine that stimulates the proliferation of activated T and NK cells and induces lymphokine-activated killer cell activity in vitro. To investigate the biological effects of recombinant human IL-12 (rHuIL-12) in vivo, two exploratory studies were conducted in squirrel monkeys (Sciureus saimiri), which have been shown to be pharmacologically responsive to rHuIL-12 in vitro.

Experimental Design: In the first study, 18 monkeys (3/sex/group) were given daily subcutaneous injections of 0 (vehicle control), 10, or 50 micrograms/kg/day rHuIL-12 for 14 days.

Interleukin-12: a cytokine with therapeutic potential in oncology and infectious diseases.

IL-12 is a cytokine that promotes cell-mediated immunity by promoting Th1-type cytokine responses, enhancing the lytic activity of NK/LAK cells, augmenting specific CTL responses, and inducing the production of IFN-gamma. On the other hand, IL-12 suppresses the development of Th2-type cytokine responses and humoral immunity, particularly IgGl and IgE responses. It is likely that IL-12 normally plays an important role in the host defense against intracellular microbial pathogens.

In vivo toxicological effects of rel A antisense phosphorothioates in CD-1 mice.

To characterize the in vivo toxicity of phosphorothioate antisense oligonucleotides against rel A (p65 subunit of NF-kappa B transcription factor), forty-eight 6-week-old CD-1 mice were split into 4 groups (6/sex/group) receiving vehicle (phosphate-buffered saline) or doses of 50, 100, and 150 mg/kg of rel A antisense oligonucleotides intraperitoneally 3 times weekly for 2 weeks. Clinical signs of toxicity included weakness, and decreased motor activity and food consumption with body weight loss. Mortality occurred in 7 of 12 mice in the 150-mg/kg group and in 2 of 12 mice in the 100-mg/kg group, most of which died within the first 2 to 4 days of treatment.

Administration of recombinant IL-12 to normal mice enhances cytolytic lymphocyte activity and induces production of IFN-gamma in vivo.

IL-12 is a heterodimeric cytokine that has been shown to enhance natural killer (NK) and cytotoxic T lymphocyte (CTL) responses, and to induce IFN-gamma production in vitro. In this study, we have examined the effects in vivo of administering purified murine rIL-12 to normal mice. Daily injections of rIL-12 i.

Antisense inhibition of the p65 subunit of NF-kappa B blocks tumorigenicity and causes tumor regression.

The NF-kappa B transcription factor, composed of two proteins, p50 and p65, is a pleiotropic activator that participates in the induction of a wide variety of cellular genes. Various cell adhesion molecules have NF-kappa B binding sites and may play an important role in inflammatory response, tumorigenicity, and metastasis. In an earlier study, we demonstrated that adhesion of diverse transformed cells was blocked by antisense inhibition of the p65 subunit of NF-kappa B.

A sense phosphorothioate oligonucleotide directed to the initiation codon of transcription factor NF-kappa B p65 causes sequence-specific immune stimulation.

Antisense oligonucleotides have proved effective in achieving targeted inhibition of gene expression. In such experiments, sense oligonucleotides have frequently been used as a control for nonspecific effects, but the results have been variable, raising questions about the reliability of sense oligomers as a control. It is possible that some of the effects of sense oligonucleotides may be specific.

Allelic variation in the DR subregion of the canine major histocompatibility complex.

Allelic variation in the DR subregion of the canine major histocompatibility complex (DLA) has been analyzed by nucleic acid sequencing of cDNA clones of DRB genes amplified in vitro by the reverse transcriptase-polymerase chain reaction (RT-PCR). Sequence analysis of a panel of 19 homozygous typing cell dogs representing 12 different DLA-D types (defined by mixed leucocyte reaction) demonstrated the presence of one expressed DRB locus with at least nine distinct alleles in the dog. Unique DLA-DRB alleles were found in the DLA-D types Dw1, Dw3, Dw4, Dw8 (workshop assignments) and D4, D6, D7, D8, and D9 (Seattle assignments).