A monoclonal antibody for detection of intracellular and secreted interleukin-2 in horses

Interleukin-2 (IL-2) is a T cell growth factor and major modulator of T helper (Th) cell differentiation. Here, we have developed and characterized a monoclonal antibody to equine IL-2 (anti-IL-2 mAb, clone 158-1). The IL-2 mAb detected rIL-2 by ELISA, intracellular staining and flow cytometry analysis and Western blotting. The IL-2 mAb was also paired with a polyclonal IL-2 detection antibody in both ELISA and a fluorescent bead-based assay. When these two assays were compared using identical reagents there was an improved analytical sensitivity (46pg/ml) and wider linear quantification range (46-100,000pg/ml) of IL-2 quantification using the fluorescent bead assay. Equine rIL-2 standards were expressed in both yeast and mammalian cells but the mammalian cell-expressed rIL-2 standard was found to be most accurate for native IL-2 quantification. Using this system we found that stimulation of equine peripheral blood mononuclear cells (PBMC) with phorbol 12-myristate 13-acetate (PMA) and ionomycin induced IL-2 secretion most potently. Pokeweed mitogen (PWM) consistently resulted in low amounts of IL-2 from PBMC, while concanavalin A (ConA), phytohemagglutinin-L (PHA-L) and lipopolysaccharide (LPS) either marginally stimulated or failed to stimulate IL-2 secretion from equine PBMC. After stimulation of equine PBMC with PMA and ionomycin, IL-2 production was detected in 13.0% (range 7.5-16.8%) of the lymphocytes by flow cytometric analysis. IL-2 expression was mainly stimulated in CD4⁺ cells, in a sub-population of CD8⁺ cells, and also in CD4-/CD8- cell population. In addition, both IFN-γ⁺/IL-2⁺ and IL-4⁺/IL-2⁺ producing cells were observed. Testing of serum and colostrum samples from 15 healthy horses showed that IL-2 was not detectable in these samples (<46pg/ml). In summary, the equine IL-2 mAb provides a new tool for the characterization of IL-2 producing equine cells and the quantification of secreted equine IL-2 in sensitive assays.

Infection of peripheral blood mononuclear cells with neuropathogenic equine herpesvirus type-1 strain Ab4 reveals intact interferon-α induction and induces suppression of anti-inflammatory interleukin-10 responses in comparison to other viral strains

The recent increase in incidence, morbidity, and mortality of neurological disease induced by equine herpesvirus type 1 (EHV-1) has suggested a change of virulence of the virus. The exact mechanisms by which EHV-1 induces neurologic disease are not known. Environmental, viral, and host risk factors might contribute to neurological manifestation. Here, we investigated innate interferon-α (IFN-α), interleukin-10 (IL-10) and IL-4 responses after infection of equine peripheral blood mononuclear cells (PBMC) with EHV-1 using an available cytokine multiplex assay. Three viral strains representing an older isolate (RacL11), a recent abortigenic (NY03) and a neuropathogenic isolate (Ab4) were compared to identify differences in cytokine induction that might explain the increased pathogenicity of Ab4. Cytokine concentrations were also compared between foals, mares after birth, pregnant and non-pregnant mares to investigate whether immune responses to EHV-1 infection are influenced by age or pregnancy status. PBMC from all groups secreted high concentrations of anti-viral IFN-α in response to EHV-1. A reduced response was observed in foals compared to non-pregnant mares. EHV-1 infection induced moderate IL-10 and overall low IL-4 secretion. Ab4 infection resulted in a significant reduction of IL-10 responses in adult horses. IL-10 and IL-4 responses were lower in foals than in most mare groups. These data suggested that EHV-1 induces robust IFN-α secretion without major differences between viral strains. However, anti-inflammatory IL-10 production was significantly reduced after infection with neuropathogenic Ab4. The ability of this EHV-1 isolate to down-regulate IL-10 production might contribute to increased local inflammation and a higher risk for neurological manifestation of the disease after infection with Ab4.

Autoimmunity and avoidance learning in NXRF recombinant inbred strains

Four recombinant inbred (RI) strains, generated from NZB and RF progenitors, were tested on a two-way shuttlebox and their sera were assayed for serological factors. The four RI strains differed with respect to number of null responses and escape time. The strain with the poorest performance displayed the greatest degree of autoimmunity. The avoidance measures were correlated against the autoimmune serological parameters for the four RI strains and the two progenitors. The number of avoidances was negatively correlated with anti-DNA antibody titer, while the number of null responses showed a positive association with immune complex level. Escape time had positive correlations with IgG, IgM-RF, and immune complexes. These findings are consistent with, and extend, our prior reports that avoidance learning is inversely related to the degree of autoimmunity.

Alzheimer's dementia: performance on parallel forms of the dementia assessment battery

Fifty-four patients with Alzheimer's disease performed on the Dementia Assessment Battery that comprised of finger tapping, forward digit span, naming, verbal memory, visual memory, Token Test, digit cancellation, word-list generation, symbol-digit substitution, and copying geometric designs. Four forms of the battery were administered at weekly intervals. The equivalence of the forms, the relative difficulty of the tests, retest reliability, and factorial composition of the battery are presented. Performance improved with repetition. Impairments in visuo-spatial and verbal abilities were independent of each other. The fragility of the patients' working memory was identified as a main cause for their poor recall. The importance of "component analysis" in individual assessment is illustrated.

Multicenter trial of naloxone in Alzheimer's disease

In a double-blind, placebo-controlled, crossover study of intravenously administered naloxone hydrochloride, 54 subjects with clinically ascertained Alzheimer's disease tested at three university centers showed no significant improvement in neuropsychological performance after 1-mg or 10-mg doses; 15 patients at 1 center were similarly unimproved after receiving 30 mg naloxone (single blind). Findings fail to support claims that naloxone monotherapy ameliorates cognitive impairments of Alzheimer's disease.

Three sex dimorphisms in the granule cell layer of the hippocampus in house mice

Inbred strains of mice differ in number of neurons in the dentate granule cell layer of hippocampus and in granule cell density. In a study of both sexes in 6 strains, females had significantly lower granule cell density than males of the same strain. Females of strains with high neuron numbers had significantly fewer granule cells than males of the same strain, while males and females of low neuron number strains did not differ from each other. Sizes of neuronal nuclei were examined in males and females of two strains. No significant strain difference was found, but females had significantly smaller nuclei. The results suggest that hippocampal function is associated with the differing adaptive roles of male and female house mice.

An association between granule cell density in the dentate gyrus and two-way avoidance conditioning in the house mouse

Mice with genetically associated variations in the number and density of granule cells in the dentate gyrus were tested for open-field activity, spatial maze learning, and two-way avoidance conditioning. The number of granule cells was not associated with any behavior measured. Only avoidance conditioning was related to granule cell density, which had a negative correlation with performance on the shuttle box task. This result was replicated in two genetically different stocks of mice. Density of the more caudal portion of the dentate was associated with early stages of avoidance learning, whereas the more rostral portion was associated with later stages. The results are discussed in relation to theories of functional dissociation within the hippocampus.

An association between granule cell density in the dentate gyrus and two-way avoidance conditioning in the house mouse

Mice with genetically associated variations in the number and density of granule cells in the dentate gyrus were tested for open-field activity, spatial maze learning, and two-way avoidance conditioning. The number of granule cells was not associated with any behavior measured. Only avoidance conditioning was related to granule cell density, which had a negative correlation with performance on the shuttle box task. This result was replicated in two genetically different stocks of mice. Density of the more caudal portion of the dentate was associated with early stages of avoidance learning, whereas the more rostral portion was associated with later stages. The results are discussed in relation to theories of functional dissociation within the hippocampus.

Supplementary report: behavioral differences in mice genetically selected for brain weight

Locomotor activity and performance on several different learning tasks were measured in mice genetically selected for high brain weight and in unselected control lines. Brain size was found to be positively related to locomotor activity in an open field and to performance on brightness discrimination-learning and active avoidance tasks and negatively related to passive avoidance performance. The results provide support for the findings of a previous study on these animals and add further information on the nature of the brain size and behavior relationship.

Some behavioral differences in mice genetically selected for high and low brain weight

Learning ability, exploratory behavior, and emotionality were measured in mice genetically selected for high and low total brain weight. The high selection lines scored significantly higher than the low lines in locomotor activity in the open field and discrimination learning performance in a water maze, and these findings were supported by correlations between brain weight and behavioral scores within unselected control lines. There is some evidence that these behavioral differences are associated with general changes in brain size produced by genetic selection.