Endogenous Immune Response to Glutamic Acid Decarboxylase (GAD67) in NOD Mice is Modulated by Adjuvant Immunotherapy

We have shown that immunization of non-obese diabetic (NOD) mice with adjuvants (CFA or BCG) prevents the onset of diabetes by induction of regulatory cells. Since autoimmune responses to glutamic acid decarboxylase (GAD) are up-regulated in insulin-dependent diabetes mellitus (IDDM), in this study GAD67-specific antibody, T cell proliferation and lymphokine production patterns were analysed in the adjuvant-treated mice to characterize the regulatory mechanisms underlying the protection. We used both spontaneous diabetes and syngeneic islet transplantation models in NOD mice. Protection against spontaneous diabetes and prevention of syngeneic islet graft rejection by CFA or BCG treatment was found to be accompanied by the production of long lasting and high titre anti-GAD67 antibody of IgG1 isotype in the sera. Uponin vitrostimulation with GAD67, draining lymph node and spleen cells from CFA-immunized NOD mice or syngeneic islet-grafted and BCG-protected NOD mice produced much more IL-4, whereas there was no significant change in IFN-γ production. The strong early T cell proliferative response to GAD67 in CFA or BCG-immunized NOD mice was followed by a low or unresponsiveness state. Taken together, these results suggest a shift in Th1/Th2 balance in the GAD67-specific endogenous immune response to a change in Th2 levels after adjuvant treatment. We postulate that the protective effect of CFA or BCG is due to the diversion of GAD-specific endogenous cellular immune response to a non-pathogenic humoral response.     

In vivo activation of NK cells induces inhibition of lung colonization of H-2 positive and H-2 negative fibrosarcoma tumor clones

The role of different tilorone analogs in the abrogation of the metastatic spread of H-2 positive and H-2 negative tumor clones was studied. Pre-treatment of BALB/c mice with RMI 10,874DA compound completely abolished lung colonization of an H-2 negative (GR9.B9) MCA-induced fibrosarcoma clone in an experimental metastasis assay. This effect was also evident when clones were treated with other tilorone analogs (R11,567DA or R11,513DA). Other H-2 positive and H-2 negative chemically induced fibrosarcoma clones were also tested. The effect was not due to direct toxicity of the tilorone analog on tumor cells, but instead was dependent on NK cells; this was suggested by the finding that treatment of mice with anti-asialo GM₁ abrogated the effect of the tilorone analog (RMI 10,874DA compound). Interestingly, the inhibition of lung colonization after intravenous injection was again observed regardless of the H-2 phenotype of the tumor clones, and H-2⁺ and H-2^– clones were similarly inhibited.In vitro assays of NK sensitivity of tumor clones showed that lysis varied depending on the H-2 phenotype of tumor clones, indicating an absence of correlation betweenin vivo andin vitro results.     

T-lymphocyte activation in IgA nephropathy: Serum-soluble interleukin 2 receptor level,interleukin 2 production,and interleukin 2 receptor expression by cultured lymphocytes

The present study was undertaken to examine the T-lymphocyte activation in IgA nephropathy. Serum-soluble interleukin 2 receptor (sIL2R) levels were studied in 29 IgA nephritic patients, 17 patients with chronic glomerulonephritis (non-IgA nephropathy), and 30 healthy controls during an infection-free period. No difference in serum sIL2R level was demonstrated among these three groups of subjects. However, the serum sIL2R levels of IgA nephritic patient rose significantly during clinical exacerbation with synpharyngitic macroscopic hematuria and the serum sIL2R levels fell when hematuria subsided. Mitogen-stimulated cellular interleukin 2 receptor (IL2R) expression, sIL2R release, and interleukin 2 (IL2) production were also examined in peripheral blood mononuclear cells (PBMC) cultured for 24–48 hr in 21 patients with IgA nephropathy, 17 patients with chronic glomerulonephritides, and 17 healthy controls. The total cellular IL2R expression and sIL2R release did not differ among these three groups of subjects. However, the individual T-cell subsets bearing IL2R were distinctly different between IgA nephritic patients and the other two groups of controls. IgA nephritic patients had increased activated CD4+ lymphocytes and reduced activated CD8+ lymphocytes. Furthermore, IL2 production in response to phytohemagglutinin and pokeweed mitogen stimulation was increased in lymphocytes from patients with IgA nephropathy. The IL2 production did not correlate with the quantities of cellular and sIL2R yet the cellular IL2R expression paralleled the sIL2R released by cultured lymphocytes. Our present study suggests that the T lymphocytes from patients with IgA nephropathy have a defect in overproduction of IL2 and increased activated T helper-cell subset upon mitogenic stimulation. Serum measurement of sIL2R could potentially be useful in monitoring the disease activity.     

The effect of prostaglandin E2 and ADH on diffusional water permeability in the collecting duct of an isolated rat papilla

The effect of prostaglandin on diffusional water permeability has been studied in collecting ducts in an isolated rat papilla. PGE₂ increased water permeability. The effect was significant at a concentration of 10^–8 mol l^–1 and was maximal with a concentration of 10^–6 mol l^–1. The maximal increment of 0.94±0.10 (SEM) m s^–1 was approximately half that produced by maximal stimulation with antidiuretic hormone (2.18±0.12 m s^–1).A concentration of 10^–8 mol l^–1 produced an increase in basal water permeability and 25 unit ml^–1 ADH, which without PGE₂ present gave a similar increase, had no incremental effect. ADH 100 unit ml^–1 increased permeability to a value similar to that observed in the absence of PGE₂. Thus PGE₂ and ADH both increase water permeability but the increments are not additive.Indomethacin in a concentration that inhibited prostaglandin production altered the response of the collecting duct to ADH. The dose response curve was shifted to the left and the maximal increase in water permeability and the lowest dose at which a response occurred took place at concentrations less than 1/2 those required in its absence.Prostaglandins influence the action of ADH and it is likely that in life they regulate and modulate the change in water permeability induced by anti-diuretic hormone.     

Presynaptic inhibition leading to disinhibition of acetylcholine release from interneurons of the caudate nucleus: Effects of dopamine, β-endorphin and d-Ala2-Pro5-enkephalinamide

The release of acetylcholine from slices of the rat striatum has been studied in two groups of animals: untreated rats and rats pretreated by intracerebroventricular injections of 6-hydroxydopamine in doses sufficient partially or completely to destroy the nigrostriatal dopaminergic tract. The amount of acetylcholine released was much greater, both under resting conditions and in the presence of ouabain. from striatal slices from the latter group. Dopamine, β-endorphin, d-Ala²-Pro⁵-enkephalinamide and morphine enhanced the ouabain-induced release of acetylcholine from normal striatal slices, but inhibited the release of acetylcholine from striatal slices of 6-hydroxydopamine pretreated rats Naloxone prevented the effects of the opioid peptides.Thus there appear to be receptors, both on the cholinergie interneurons of the striatum and on the terminals of dopaminergic fibres, which are sensitive to dopamine, β-endorphin, enkephalin and morphine. Dopamine, released from nigrostriatal neurons, inhibits acetylcholine release from striatal interneurons. It is suggested that β-endorphin, or some other enkephalin-like peptide present in the striatum, might moderate the dopaminergic inhibition of acetylcholine release by presynaptically inhibiting the release of dopamine. A disinhibition phenomenon of this type might play an important role in the modulation of neurochemical transmission.     

Absence of TREM2 polymorphisms in patients with Alzheimer's disease and Frontotemporal Lobar Degeneration

Triggering Receptor Expressed on Myeloid cells (TREM)2 deficiency originates a genetic syndrome characterized by bone cysts and presenile dementia, named Nasu-Hakola disease (NHD). Early onset dementia and marked involvement of frontal regions are features characterizing both NHD and other kinds of neurodegenerative disorders, such as Frontotemporal Lobar Degeneration (FTLD), and, in some cases, Alzheimer's disease (AD). Three Single Nucleotide Polymorphisms (SNPs) in TREM2 coding region were screened by allelic discrimination in a population of probable AD patients as well as FTLD patients as compared with age-matched controls. In addition, mutation scanning of the coding region of TREM2 gene was carried out in 7 patients with early onset AD (EOAD), 16 FTLD, and 20 controls. None of the SNPs analyzed was present, either in patients or controls. Moreover, mutation scanning of the five exons of TREM2 failed to detect the presence of novel polymorphisms. These data demonstrate that TREM2 coding region is highly conserved, implying a crucial role of this receptor. Further studies, including a functional analysis, are certainly required to clarify the role of TREM2 in neurodegenerative processes.     

Beta-catenin abnormalities and associated insulin-like growth factor overexpression are important in phyllodes tumours and fibroadenomas of the breast

The aim of this study was to assess the expression of IGF-I and IGF-II in phyllodes tumours and fibroadenomas and to see if there is any correlation between nuclear beta-catenin expression and IGF-I and IGF-II expression in these tumours. In a previous study, it has been shown that Wnt signalling is important in the pathogenesis of phyllodes tumours of the breast. Epithelial Wnt5a overexpression and stromal Wnt2 overexpression were associated with abnormal, nuclear localization of beta-catenin in the stromal cells of these tumours. However, not all tumours with beta-catenin accumulation showed Wnt overexpression. One other possible cause of beta-catenin accumulation is overexpression of insulin-like growth factors (IGFs), as both IGF-I and IGF-II have been shown to stabilize beta-catenin. In this study, 30 fibroadenomas of the breast were assessed for beta-catenin expression using immunohistochemistry and the results were compared with previous data from 119 phyllodes tumours. In situ hybridization was used to assess IGF-I and IGF-II expression in 23 phyllodes tumours and 16 fibroadenomas. Nineteen phyllodes tumours (83%) showed widespread overexpression of IGF-II and 5/23 (22%) showed widespread overexpression of IGF-I. IGF-I expression correlated with nuclear beta-catenin staining in phyllodes tumours. Malignant phyllodes tumours showed no or little IGF-I expression. There was a degree of nuclear beta-catenin expression in the stroma (weak in 33%, moderate in 27%, and strong in 40%) in all fibroadenomas and nuclear beta-catenin staining correlated with IGF-I overexpression. Extensive IGF-II overexpression was also found in the majority of fibroadenomas (12/16). These results support the hypothesis that IGF-I and IGF-II overexpression may be important in the pathogenesis of fibroepithelial neoplasms of the breast and that IGF-I overexpression is likely to be contributing to the nuclear beta-catenin localization observed in the tumours.     

Characterization of mouse allergens

The major allergens present in mouse skin, serum, and urine have been identified. Skin extracts, serum, and urine were chromatographed, and the activities of the fractions were monitored by histamine release from the leukocytes of individuals sensitive to mice. Fractionation of skin extracts revealed two major allergens. The large allergen has a molecular weight of approximately 67,000 daltons and by biochemical and immunochemical criteria appears to be identical to mouse albumin. The smaller molecular weight allergen is approximately 17,000 daltons. The same two allergens are also found in mouse serum and mouse urine. Histamine release by leukocytes of individuals allergic to mice demonstrated that some individuals react predominantly to the large allergen, some to the small allergen, and one group of patients reacts to both allergens.