Effects of EDTA-Induced Hypocalcaemia and Stress on Plasma TNF-α, IL-1-ra, G-CSF, GM-CSF and S-100 in Dairy Cows

The pathophysiology of postparturient paresis is still not completely understood. Knowledge recently acquired in immunology, endocrinology and cell physiology has still to be integrated in order to elucidate the aetiopathogenesis of the disease. For that purpose, the effect of the EDTA infusion model on the plasma concentrations of selected cytokines and growth factors, and of a calcium binding protein was examined in dairy cows. Six 6- to 11-year-old Brown Swiss cows in mid lactation were infused with a 5% solution of Na2EDTA in one jugular vein over a period of 5 h. Blood samples were collected from the contralateral side daily two days before, and then hourly for five hours during the infusion, hourly for five hours after the end of the infusion, and once daily for 10 days thereafter. The plasma concentrations of cortisol, tumour necrosis factor-α, interleukin-1 receptor antagonist, granulocyte colony-stimulating factor, granulocyte and macrophage colony-stimulating factor, and the calcium binding protein S-100 were determined. Before the EDTA infusion, during the infusion and for two days thereafter, the mean plasma concentrations of cortisol were significantly higher than those from days 4 to 10 after the infusion. The plasma concentrations of tumour necrosis factor-α and interleukin-1 receptor antagonist followed a similar profile. At the end of EDTA infusion, low concentrations of granulocyte colony-stimulating factor were detected in one cow only. On days 3 and 4, the mean plasma concentrations of granulocyte colony-stimulating factor were significantly higher than the pre-infusion values, but this was followed by a significant decrease on post-infusion day 5. From day 4 to 7, the plasma concentrations of S-100 were significantly lower than the pre-infusion values. The importance of these findings in the pathophysiology of postparturient paresis remains to be establishe

Modified-live feline calicivirus vaccination elicits cellular immunity against a current feline calicivirus field strain in an experimental geline challenge study

Feline calicivirus (FCV) is a common cat virus associated with oral ulcerations and virulent-systemic disease. Efficacious FCV vaccines protect against severe disease but not against infection. The high genetic diversity of FCV poses a challenge in vaccine design. Protection against FCV has been related to humoral and cellular immunity; the latter has not been studied in detail. This study investigates the cellular and humoral immune response of specified pathogen-free (SPF) cats after modified-live FCV F9 vaccinations and two heterologous FCV challenges by the analysis of lymphocyte subsets, cytokine mRNA transcription levels, interferon (IFN)-γ release assays in peripheral blood mononuclear cells (PBMCs), anti-FCV antibodies, and neutralisation activity. Vaccinated cats developed a Th1 cytokine response after vaccination. Vaccination resulted in antibodies with neutralising activity against the vaccine but not the challenge viruses. Remarkably, IFN-γ-releasing PBMCs were detected in vaccinated cats upon stimulation with the vaccine strain and the first heterologous FCV challenge strain. After the first experimental infection, the mRNA transcription levels of perforin, granzyme B, INF-γ, and antiviral factor MX1 and the number of IFN-γ-releasing PBMCs when stimulated with the first challenge virus were higher in vaccinated cats compared to control cats. The first FCV challenge induced crossneutralising antibodies in all cats against the second challenge virus. Before the second challenge, vaccinated cats had a higher number of IFN-γ-releasing PBMCs when stimulated with the second challenge virus than control cats. After the second FCV challenge, there were less significant differences detected between the groups regarding lymphocyte subsets and cytokine mRNA transcription levels. In conclusion, modified-live FCV vaccination induced cellular but not humoral crossimmunity in SPF cats; innate immune mechanisms, secretory and membranolytic pathways, and IFN-γ-releasing PBMCs seem to be important in the host immune defence against FCV

Feline leukemia virus outbreak in the critically endangered Iberian lynx (Lynx pardinus): high-throughput sequencing of envelope variable region A and experimental transmission

The Iberian lynx is the most endangered felid species. During winter/spring 2006/7, a feline leukemia virus (FeLV) outbreak of unexpected virulence killed about 2/3 of the infected Iberian lynxes. All FeLV-positive animals were co-infected with feline hemoplasmas. To further characterize the Iberian lynx FeLV strain and evaluate its potential virulence, the FeLV envelope gene variable region A (VRA) mutant spectrum was analyzed using the Roche 454 sequencing technology, and an in vivo transmission study of lynx blood to specified-pathogen-free cats was performed. VRA mutations indicated weak apolipoprotein B mRNA editing enzyme and catalytic polypeptide-like cytidine deaminase (APOBEC) restriction of FeLV replication, and variants characteristic of aggressive FeLV strains, such as FeLV-C or FeLV-A/61C, were not detected. Cats exposed to FeLV/Candidatus Mycoplasma haemominutum-positive lynx blood did not show a particularly severe outcome of infection. The results underscore the special susceptibility of Iberian lynxes to infectious diseases

HIV-1 Infection of DC: Evidence for the Acquisition of Virus Particles from Infected T Cells by Antigen Uptake Mechanism

Dendritic cells (DC) play a pivotal role in transmission and dissemination of HIV-1. Earlier studies reported that DC present at the site of infection trap virus particles via DC-SIGN and transfer the virus to the interacting naïve T cells. This prompted us to ask the question whether DC could acquire virus from infected T cells during DC-T cell interaction. To address this, we investigated the likely transfer of virus from HIV-1 infected T cells to DC and the underlying mechanisms involved. Results indicate that DC acquire virus from infected T cells via antigen uptake mechanism and this results in infection of DC with expression of proteins directed by viral DNA. Further studies with HIV-1 lacking the Env protein also resulted in infection of DC. The use of antibodies against DC-SIGN and DC-SIGN-R ruled out a role for receptor in the infection of DC. Additional data show that DC infection is directly correlated with the ability of DC to take up antigen from infected T cells. Overall, these studies provide evidence to suggest that HIV-1, besides infecting immune cells, also utilizes immunological mechanism(s) to acquire and disseminate virus

Oral doxycycline pharmacokinetics: Lambs in comparison with sheep

The pharmacokinetics of doxycycline was investigated in lactating sheep and lambs after oral administration at a dose of 10 mg/kg. Concentrations in plasma and milk were assayed with HPLC-PDA analysis. Doxycycline penetrates into the milk, and levels (0.38 ± 0.21 μg/ml) were found 0.5 hr after the treatment. The results suggest that the lambs can be exposed to doxycycline by suckling milk from their treated mothers. Population pharmacokinetic analysis showed a positive relationship between age, which reflects the stage of development of rumen function, and clearance. Possible explanations for the observed differences include the undeveloped rumen in lambs, the differences in the feed and liver function as evidenced by the blood biochemical parameters aspartate aminotransferase (AST) and alanine aminotransferase (ALT), which were significantly lower in lambs (62.67 ± 27.83 U/L and 8.50 ± 6.80 U/L) than in sheep (114.33 ± 20.77 U/L and 18.00 ± 3.16 U/L)