Expression of three intelectins in sheep and response to a Th2 environment

Sheep intelectin1 and sheep intelectin3 (sITLN1 and sITLN3) were cloned and sequenced. The amino acid sequences of sITLN1 and sITLN3 shared 86% and 91% homology with the previously cloned sheep intelectin2 (sITLN2), respectively. Expression of sITLN1 and sITLN3 transcript was demonstrated in abomasum, lung, colon and gastric lymph node, terminal rectum, skin, jejunum, mesenteric lymph node, ileal peyer’s patches, brain, kidney, liver, spleen, skin, ear pinna, heart and ovary in normal sheep tissues. sITLN2 transcript expression was restricted to the abomasal mucosa in normal sheep tissues. Using a non selective chicken anti-intelectin antibody, tissue intelectin protein was demonstrated in mucus neck cells in the abomasum, mucus cells in the colon, free mucus in ileum, goblet cells in the lung, small intestinal epithelium and brush border, epidermal layer of the skin and skin sebaceous glands. The expression of the three sITLN transcripts was examined in two nematode infections in sheep known to induce a Th2 response; a Teladorsagia circumcincta challenge infection model and a Dictyocaulus filaria natural infection. The three sITLN were absent in unchallenged naïve lambs and present in the abomasal mucosa of both naïve and immune lambs following T. circumcincta challenge infection. Upregulation of sITLN2 and sITLN3 was shown in sheep lung following D. filaria natural infection. Intelectins may play an important role in the mucosal response to nematode infections in ruminants

Expression of Integrin-αE by Mucosal Mast Cells in the Intestinal Epithelium and Its Absence in Nematode-Infected Mice Lacking the Transforming Growth Factor-β1-Activating Integrin αvβ6

Peak intestinal mucosal mast cell (MMC) recruitment coincides with expulsion of Trichinella spiralis, at a time when the majority of the MMCs are located within the epithelium in BALB/c mice. Although expression of integrin-α(E)β(7) by MMCs has not been formally demonstrated, it has been proposed as a potential mechanism to account for the predominantly intraepithelial location of MMCs during nematode infection. Co-expression of integrin-α(E)β(7) and the MMC chymase mouse mast cell protease-1, by mouse bone marrow-derived mast cells, is strictly regulated by transforming growth factor (TGF)-β(1). However, TGF-β(1) is secreted as part of a latent complex in vivo and subsequent extracellular modification is required to render it biologically active. We now show, for the first time, that intraepithelial MMCs express integrin-α(E)β(7) in Trichinella-infected BALB/c and S129 mice. In S129 mice that lack the gene for the integrin-β(6) subunit and, as consequence, do not express the epithelial integrin-α(v)β(6), integrin-α(E) expression is virtually abolished and recruitment of MMCs into the intestinal epithelium is dramatically reduced despite significant overall augmentation of the MMC population. Because a major function of integrin-α(v)β(6) is to activate latent TGF-β(1,) these findings strongly support a role for TGF-β(1) in both the recruitment and differentiation of murine MMCs during nematode infection

Leukotriene B4, an activation product of mast cells, is a chemoattractant for their progenitors

Mast cells are tissue-resident cells with important functions in allergy and inflammation. Pluripotential hematopoietic stem cells in the bone marrow give rise to committed mast cell progenitors that transit via the blood to tissues throughout the body, where they mature. Knowledge is limited about the factors that release mast cell progenitors from the bone marrow or recruit them to remote tissues. Mouse femoral bone marrow cells were cultured with IL-3 for 2 wk and a range of chemotactic agents were tested on the c-kit+ population. Cells were remarkably refractory and no chemotaxis was induced by any chemokines tested. However, supernatants from activated mature mast cells induced pronounced chemotaxis, with the active principle identified as leukotriene (LT) B4. Other activation products were inactive. LTB4 was highly chemotactic for 2-wk-old cells, but not mature cells, correlating with a loss of mRNA for the LTB4 receptor, BLT1. Immature cells also accumulated in vivo in response to intradermally injected LTB4. Furthermore, LTB4 was highly potent in attracting mast cell progenitors from freshly isolated bone marrow cell suspensions. Finally, LTB4 was a potent chemoattractant for human cord blood–derived immature, but not mature, mast cells. These results suggest an autocrine role for LTB4 in regulating tissue mast cell numbers

Evaluation of Th1, Th2 and immunosuppressive cytokine mRNA expression within the colonic mucosa of dogs with idiopathic lymphocytic–plasmacytic colitis

The objective of this study was to evaluate the expression of the immunoregulatory and pro-inflammatory cytokines interleukin (IL)-2, IL-4, IL-6, IL-12p35, IL-12p40, interferon-gamma (IFN-γ), and tumour necrosis factor-alpha (TNF-α), and the expression of the predominantly immunosuppressive cytokines transforming growth factor-beta (TGF-β) and IL-10 in canine idiopathic lymphocytic–plasmacytic colitis (LPC). Semi-quantitative reverse transcriptase–polymerase chain reactions were performed using specific primers on RNA isolated from the colonic mucosa of healthy dogs, dogs with clinical signs of large intestinal disease but normal histopathology of the colon, and dogs with LPC. Canine LPC was associated with over-expression of IL-2 compared to healthy colonic mucosa (p<0.01) and the mucosa of dogs with large intestinal diarrhoea but normal histopathology (p<0.05). Higher levels of TNF-α mRNA were also seen in LPC compared to healthy mucosa (p<0.05). These results indicate that LPC is associated with activation of CD4+ T-helper lymphocytes and increased production of T-helper-1-type cytokines

The expression of intelectin in sheep goblet cells and upregulation by interleukin-4

Upregulation of intelectin (ITLN) transcript and protein has previously been shown in intestinal nematode infections of resistant mice strains with immunolocalisation of protein to goblet cells and paneth cells. In man, intelectin expression has been shown in respiratory tract epithelium, with upregulation occurring in bronchoalveolar lavage fluid of asthmatic individuals. This study describes the expression of intelectin in the respiratory tract of sheep and the immunolocalisation to goblet cells using a novel affinity-purified chicken anti-intelectin peptide antibody. Furthermore we show that when sheep tracheal explants were cultured for 48 h± recombinant sheep IL-4, sheep ITLN transcripts were upregulated compared with controls. Putative roles for intelectin have included an antibacterial role and an alteration of the character of mucus. Our data suggest ITLNs may play an important role in the mucosal response in allergy and parasitic infections