Characterization of antibodies specific for canine TLR4, 5 and 9 by ELISA, Western blotting and immunohistochemistry

The immunostimulatory effect of CpG oligodeoxynucleotides on peripheral blood mononuclear cells of healthy dogs and dogs with atopic dermatitis

Synthetic oligodeoxynucleotides containing cytosine phosphatidyl guanine-rich DNA sequences (CpG ODN) can promote T-helper type 1 (Th1) responses, reduce T-helper type 2 (Th2) responses and/or favour regulatory T cell (Treg) responses in vitro and in vivo in humans and animals, by acting via Toll-like receptor 9 (TLR9). Since CpG ODN can be used as immune-modulators for canine atopic dermatitis (AD), the aim of the current study was to investigate their immunostimulatory potential on peripheral blood mononuclear cells (PBMC) and their subsets, from AD and healthy dogs. Expression of TLR9 and cytokine mRNA in CpG ODN-stimulated and unstimulated cells was assessed by real-time quantitative PCR. Stimulation of PBMC with CpG class C ODN upregulated mRNA expression of interleukin (IL)-6, interferon (IFN)-γ and IL-12p40 in AD dogs (P<0.05). It also stimulated IFN-γ protein secretion by PBMC of atopic and healthy dogs as measured by ELISA. In healthy dogs only, CpG class C ODN stimulated IFN-α mRNA production by CD21(+) cells, and IL-10, IL-13 and IFN-γ mRNA production by CD3(+) cells. Increased expression of TLR9 mRNA was only observed in CD3(+) cells from AD dogs. No significantly increased gene expression was found in the CD11c(+) subset upon stimulation, for those genes evaluated. The results indicate that PBMC of healthy and atopic dogs are sensitive to stimulation with CpG ODN class C, with a resulting Th1 cytokine response in AD dogs and a mixed Th1/Th2/Treg cytokine response in healthy dogs. From this study, little evidence was found to support the use of CpG ODN class C for therapeutic purposes in dogs affected with AD.

Cytochemistry of sialoglycoconjugates and lysozyme in canine anal glands as studied by electron microscopic methods

The distribution of sialoglycoconjugates and lysozyme in the secretory cells of canine anal glands was studied by means of electron microscopic cytochemical methods, particularly lectin cytochemistry and immunocytochemistry. Sialic acids were predominantly present in the secretory granules, Golgi bodies, surface coat of the plasma membrane and luminal secretions. In addition, within these structures, the secretory granules, Golgi bodies and luminal secretions exhibited high levels of sialoglycoconjugates that terminated in Siaα2-6Gal/GalNAc or Siaα2-3Galβ1-4GlcNAc. In the secretory cells, reactive gold particles representing lysozyme were mainly detectable in the secretory granules and Golgi bodies. Sialic acids possess diverging functional properties, whereas lysozyme contributes to the non-specific defense against microorganisms. Therefore, their presence and secretion are suggestive of protective effects of both secretory products at the anal mucosa.