Lymph Node Mesenchymal and Endothelial Stromal Cells Cooperate via the RANK-RANKL Cytokine Axis to Shape the Sinusoidal Macrophage Niche

1. Download : Download high-res image (251KB)
2. Download : Download full-size image

     

N-Glycosylation contributes to the limited cross-reactivity between hemagglutinin neuraminidase proteins of human parainfluenza virus type 4A and 4B

cDNAs encoding human parainfluenza virus type 4B (hPIV-4B) hemagglutinin neuraminidase (HN) protein were cloned and the nucleotide sequences were determined. A high degree of identity (81.4%) was observed between the nucleotide sequences of hPIV-4A and -4B HN proteins, and an 87.3% identity was found between the deduced amino acid sequences. This degree of identity is considered to be greater than immunological similarity between hPIV-4A and -4B HN proteins determined using monoclonal antibodies. To elucidate the causes of the antigenic difference between HN proteins of hPIV-4A and -4B, we constructed three cDNAs of hPIV-4B HN whose potential N-glycosylation sites were partially or completely the same as in hPIV-4A HN cDNA. We compared the antigenicity of the expressed wild-type and mutant proteins, and found that the antigenicities of the mutant hPIV-4B HN proteins were more similar to the hPIV-4A HN protein than to the non-mutant hPIV-4B HN protein. This study indicated that the antigenic diversity between hPIV-4A and -4B was partly caused by deletion or creation of glycosylation sites, showing that the point mutations resulting in deletion or creation of glycosylation sites is one of the initial steps leading to the division of virus into subtypes. Received: 21 January 2000     

Ganglion cell density and oil droplet distribution in the retina of brown-eared bulbul (Hysipetes amaurotis)

This study was intended to determine the number and density of both retinal ganglion cells and the oil droplets of cone photoreceptor cells in brown-eared bulbul (Hysipetes amaurotis). For this study birds were killed with proper dose of anesthetic (pentobarbital, 30 mg/kg), and the eyes were removed from the orbital cavity to isolate the retina. For the ganglion cell study retinal whole-mount specimens were prepared and stained with 0.1% cresyl violet. The different types of oil droplets were counted from color microphotographs of freshly prepared retinal samples. The mean total number of ganglion cells was estimated at approximately 2.5×10⁶; with an average density of 16 523 cells/mm². Two high-density areas, namely the central area (CA) and the dorso-temporal area (DTA), are located in the central and dorso-temporal retinas, respectively, in bulbuls (24 032 cells/mm² in the CA; 23 113 cells/mm² in the DTA). Small ganglion cells persisted in the highest density areas, whereas the largest soma sizes were found in the lowest density areas of the retina. Four types of different colored oil droplets — red, orange, green and clear — were identified with an average density of 29 062/mm². Among the different colors, the green oil droplets had a significantly higher population (13 083/mm²) than the others across the retina. The central retina had a significantly higher number of all types of oil droplets, at a density of 60 552/mm². The density and size of the different colored oil droplets were inversely related across the regions of the retina. Taken together, it is concluded that the CA of the retina is an excellent quality area for visual perception due to peak density of ganglion cells and oil droplets. Moreover, each specific oil droplet makes a distinct contribution to visual perception, thereby ensuring that the bird has a retina that best matches its natural environment and feeding behavior.     

Neural mechanisms of three-dimensional vision

We can see things in three dimensions because the visual system re-constructs the three-dimensional (3D) configurations of objects from their two-dimensional (2D) images projected onto the retinas. The purpose of this paper is to give an overview of the psychological background and recent physiological findings concerning three-dimensional vision. Psychophysical and computational studies have suggested that in the visual system the 3D surface orientation is first estimated independently from individual depth cues--such as binocular disparity, as well as various monocular cues including texture gradients--and then the information from these different depth cues is integrated to construct a generalized representation of the 3D surface geometry. Neurons involved in low-level disparity processing, or the detection of local absolute disparity, were found mainly in the occipital cortex, whereas neurons involved in high-level disparity processing, or the reconstruction of 3D surface orientation through the computation of disparity gradients, were found mainly in the parietal area caudal intraparietal sulcus (CIP). Neurons sensitive to texture gradients, which is one of the major monocular cues, were also found in CIP. The majority of these neurons were sensitive to disparity gradients as well, suggesting their involvement in the computation of 3D surface orientation. In CIP, neurons sensitive to multiple depth cues were widely distributed together with those sensitive to a specific depth cue, suggesting CIP's involvement in the integration of depth information from different sources. In addition, human and monkey imaging studies have indicated convergence of multiple depth cues in CIP. These neurophysiological findings suggest that CIP plays a critical role in 3D vision by constructing a generalized representation of the 3D surface geometry of objects.     

Oral immunization with ATP-dependent protease-deficient mutants protects mice against subsequent oral challenge with virulent Salmonella enterica serovar typhimurium

We evaluated the efficacy of mutants with a deletion of the stress response protease gene as candidates for live oral vaccine strains against Salmonella infection through infection studies with mice by using a Salmonella enterica serovar Typhimurium mutant with a disruption of the ClpXP or Lon protease. In vitro, the ClpXP protease regulates flagellum synthesis and the ClpXP-deficient mutant strain exhibits hyperflagellated bacterial cells (T. Tomoyasu et al., J. Bacteriol. 184:645-653, 2002). On the other hand, the Lon protease negatively regulates the efficacy of invading epithelial cells and the expression of invasion genes (A. Takaya et al., J. Bacteriol. 184:224-232, 2002). When 5-week-old BALB/c mice were orally administered 5 x 10(8) CFU of the ClpXP- or Lon-deficient strain, bacteria were detected with 10(3) to 10(4) CFU in the spleen, mesenteric lymph nodes, Peyer's patches, and cecum 1 week after inoculation and the bacteria then decreased gradually in each tissue. Significant increases of lipopolysaccharide-specific immunoglobulin G (IgG) and secretory IgA were detected at week 4 and maintained until at least week 12 after inoculation in serum and bile, respectively. Immunization with the ClpXP- or Lon-deficient strain protected mice against oral challenge with the serovar Typhimurium virulent strain. Both the challenged virulent and immunized avirulent salmonellae were completely cleared from the spleen, mesenteric lymph nodes, Peyer's patches, and even cecum 5 days after the challenge. These data indicate that Salmonella with a disruption of the ATP-dependent protease ClpXP or Lon can be useful in developing a live vaccine strain.     

Lipoteichoic acids from Lactobacillus strains elicit strong tumor necrosis factor alpha-inducing activities in macrophages through Toll-like receptor 2

Lactobacilli are nonpathogenic gram-positive inhabitants of microflora. At least some Lactobacillus strains have been postulated to have health beneficial effects, such as the stimulation of the immune system. Here we examined the stimulatory effects of lactobacilli on mouse immune cells. All six heat-killed Lactobacillus strains examined induced the secretion of tumor necrosis factor alpha (TNF-alpha) from mouse splenic mononuclear cells, albeit to various degrees. When fractionated subcellular fractions of Lactobacillus casei were tested for NF-kappaB activation and TNF-alpha production in RAW264.7, a mouse macrophage cell line, the activity was found to be as follows: protoplast > cell wall > polysaccharide-peptidoglycan complex. Both crude extracts and purified lipoteichoic acids (LTAs) from two Lactobacillus strains, L. casei and L. fermentum, significantly induced TNF-alpha secretion from RAW264.7 cells and splenocytes of C57BL/6, C3H/HeN, and C3H/HeJ mice but not from splenocytes of C57BL/6 TLR2(-/-) mice. Lactobacillus LTA induced activation of c-Jun N-terminal kinase activation in RAW264.7 cells. Furthermore, in HEK293T cells transected with a combination of CD14 and Toll-like receptor 2 (TLR2), NF-kappaB was activated in response to Lactobacillus LTA. Taken together, these data suggest that LTAs from lactobacilli elicit proinflammatory activities through TLR2.     

Intracerebroventricular administration of NPY stimulates resistin gene expression in mice

Resistin is thought to cause insulin resistance and link obesity to type 2 diabetes mellitus. However, little is known about the effects of neuropeptide Y (NPY) on resistin gene expression in white adipose tissue (WAT). Resistin gene expression was determined by northern blot analysis in food-deprived mice after NPY administration. Administered NPY (1 nmol/mouse) significantly increased resistin mRNA expression in WAT by 72% compared with artificial cerebrospinal fluid treated controls. These observations indicate that NPY might have a role in regulating resistin gene expression in WAT and that the novel brain-fat axis might be involved in the pathogenesis of obesity and related diseases.     

Purification, cDNA cloning, and secretory properties of FLRG protein from PC12 cells and the distribution of FLRG mRNA and protein in rat tissues

A 35 kD protein was isolated and purified from conditioned media of Bcl-2 cDNA-transfected PC12 cells and its cDNA cloned. A database analysis showed that the 35 kD protein is a rat homologue of the human FLRG protein. The biochemical as well as morphological properties of the rat FLRG protein in PC12 cells were examined and its distribution in rat tissues determined. The levels of FLRG mRNA expressed were low during the fetal period, compared with those of follistatin mRNA. The distribution of FLRG and follistatin mRNAs differed from each other after birth; the expression levels of FLRG mRNA were abundant in the adrenal gland and testis, whereas those of follistatin mRNA and activin A were markedly high in the ovary. The presence of FLRG mRNA and/or protein was confirmed in spermatocytes at various differentiating stages andin endocrine cells of both the adrenal cortex and medulla. When overexpressed in PC12 cells, the FLRG protein was found to be stored in secretory granules of the cells and largely secreted by a regulated pathway, while activin A enhancedthe constitutive secretion of the FLRG protein from wild-typpe PC12 cells, indicating that the FLRG protein possesses dualproperties in secretory pathways. The different distribution between FLRG and follistatin mRNA suggests that, like follistatin in the ovary, the FLRG protein may be involved in the maintenance of spermatogenesis in the testis and the growth and function of adrenal tissue cells, probably by regulating the functions of its binding partners such as the TGF-beta ( superfamily members.     

Development of a particle agglutination assay system for detecting Japanese encephalitis virus-specific human IgM,using hydroxyapatite-coated nylon beads

Japanese encephalitis virus-specific IgM is a reliable indicator for serodiagnosis of Japanese encephalitis. A particle agglutination (PA) assay system was developed to detect anti-Japanese encephalitis virus IgM in human serum samples. The newly developed PA assay consisted of hydroxyapatite-coated nylon beads and V-bottom 96-well microplates. Hydroxyapatite-coated nylon beads were coated with Japanese encephalitis virus antigens. Japanese encephalitis virus antigen-coated, hydroxyapatite-coated nylon beads agglutinated in the IgM-captured wells when anti-Japanese encephalitis virus IgM-positive serum samples were used. A button pattern was formed at the bottom of the wells when anti-Japanese encephalitis virus IgM-negative serum samples were used. Thirty anti-Japanese encephalitis virus IgM-positive serum samples from Japanese encephalitis-confirmed cases were tested by the PA assay. All these serum samples were determined to be Japanese encephalitis virus IgM-positive. IgM titers determined by the PA assay corresponded to those determined by enzyme-linked immunosorbent assay. The titers were consistent in two independent PA assays. These results indicate that the newly developed PA assay is a reliable method for detecting anti-Japanese encephalitis virus IgM in human serum samples and that this assay will be a suitable diagnostic system especially in rural areas of Asia.     

Oral disodium cromoglycate and ketotifen for a patient with eosinophilic gastroenteritis, food allergy and protein-losing enteropathy

We present a case report of a 10 years old boy with protein-losing enteropathy and eosinophilic gastroenteritis who had positive histamine release tests, increased allergen-specific IgE antibodies to some food items, and low levels of total serum protein and albumin. Upper gastrointestinal endoscopy revealed a number of polyps and diffuse gastritis. Biopsy specimens of the stomach and duodenum showed widespread eosinophilia and neutrophilia. Although a restricted diet was recommended, a diet which excluded foods with positive results to both histamine release test and allergen-specific IgE antibodies was poorly tolerated, and the patient rejected systemic administration of corticosteroids. Thus, we initiated an oral disodium cromoglycate (DSCG) and ketotifen therapy. After oral DSCG and ketotifen administration, the patient's condition improved gradually. Therefore, oral DSCG and ketotifen therapy might be considered as treatment option in patients with eosinophilic gastroenteritis and protein-losing enteropathy caused by food allergy.