Piotr Bąska

Increased concentration of serum TNF alpha and its correlations with arterial blood pressure and indices of renal damage in dogs infected with Babesia canis

Canine babesiosis is a tick-borne disease caused by parasites of the genus Babesia. Tumour necrosis factor alpha (TNF-α) is a cytokine that plays a role in the pathogenesis of canine babesiosis. In this study, the authors determined the concentration of serum TNF-α in 11 dogs infected with Babesia canis and calculated Spearman’s rank correlations between the concentration of TNF-α and blood pressure, and between TNF-α and indices of renal damage such as: fractional excretion of sodium (FE(Na+)), urinary creatinine to serum creatinine ratio (UCr/SCr), renal failure index (RFI), urine specific gravity (USG) and urinary protein to urinary creatinine ratio (UPC). The results demonstrated statistically significant strong negative correlations between TNF-α and systolic arterial pressure (r = −0.7246), diastolic arterial pressure (r = −0.6642) and mean arterial pressure (r = −0.7151). Serum TNF-α concentration was also statistically significantly correlated with FE(Na+) (r = 0.7056), UCr/SCr (r = −0.8199), USG (r = −0.8075) and duration of the disease (r = 0.6767). The results of this study show there is an increase of serum TNF-α concentration during canine babesiosis, and the increased TNF-α concentration has an influence on the development of hypotension and renal failure in canine babesiosis. This probably results from the fact that TNF-α is involved in the production of nitric oxide and induction of vasodilation and hypotension, which may cause renal ischaemia and hypoxia, and finally acute tubular necrosis and renal failure.

Molecular cloning and characterisation of in vitro immune response against astacin-like metalloprotease Ace-MTP-2 from Ancylostoma ceylanicum.

Ancylostoma ceylanicum belongs to the group of parasites commonly known as hookworms, blood-sucking nematodes which infect around 576 million people and hundreds of millions of animals. The interactions between these parasites and host immune systems are complicated and yet to be determined. Hookworm infections are usually long lasting and recurrent, due in part to their ability to synthesize macromolecules capable of modulating the host immune response. The interaction of parasite proteins with host immune systems has been proven, but so far there is no data describing the influence of astacin-like metalloproteases (expressed among different parasitic nematodes) on the human immune system. The cDNA encoding A. ceylanicum metalloprotease 2 (Ace-mtp-2) was cloned using RACE-PCR. Computational analysis was used to examine the immunogenicity and recombinant Ace-MTP-2 was used to investigate its influence on human THP-1 monocytes and macrophages. The Ace-mtp-2 gene encodes an astascin-like metalloprotease, with a theoretical molecular mass of 26.7 kDa. The protease has a putative signal peptide, 11 potential phosphorylation sites, and two disulfide bridges revealed by computational analysis. Maximal expression of Ace-mtp-2 by A. ceylanicum occurs in the adult stage of the parasite, and Western blot indicates the secretory nature of the protease. This suggests the protease is working at the host-parasite interface and would likely be exposed to the hosts immune response. Recombinant protein were expressed in Escherichia coli and Pichia pastoris. Recombinant Ace-MTP-2 amplified the in vitro release of TNFα and induced release of IFNγ by lipopolysaccharide activated THP-1 macrophages. The presence of Ace-MTP-2 in secretory products of the adult parasite and the induction of IFNγ release may suggest an important role for Ace-MTP-2 in host-parasite interactions since IFNγ is suggested to be responsible for the protective immune response against adult hookworms.

Characterization and differential expression of cathepsin L3 alleles from Fasciola hepatica.

Fasciola hepatica infections cause significant global problems in veterinary and human medicine, including causing huge losses in cattle and sheep production. F. hepatica host infection is a multistage process and flukes express papain-like cysteine proteases, termed cathepsins, which play pivotal roles in virulence through host entry, tissue migration and immune evasion. Expression of these proteases is developmentally regulated. Recent studies indicate that excystment of infective larvae is dependent on cysteine proteases and together FhCL3 and FhCB account for over 80% of total protease activity detectable in newly excysted juvenile (NEJ) fluke. This paper focuses on members of the cathepsin L gene family, specifically those belonging to the CL3 clade. The cDNA of two novel cathepsin L3 proteases--FhCL3-1 and FhCL3-2 were cloned. The mRNA transcript expression levels for these enzymes were significantly different at various time points in life development stages obtained in vitro, from dormant metacercariae to NEJ 24h after excystment. Maximum expression levels were observed in NEJ immediately after excystment. In all stages examined by Real Time PCR, FhCL3-2 was expressed at a higher level compared to FhCL3-1 which was expressed only at very low levels. Western blot and immunohistochemical analysis also indicated higher expression of the FhCL3-2 allele and its secretory nature. The ability of antibody responses from rats and sheep challenged with F. hepatica to recognize recombinant FhCL3-1 and FhCL3-2 was shown to differ. Differences were also confirmed through the use of anti-rFhCL3-1 and anti-rFhCL3-2 sera in Western blot analysis of juvenile excretory/secretory (ES) material separated by 2D electrophoresis. These results indicate analysis of relative expression of parasite virulence factors from different populations is required, as this will likely impact the effectiveness of vaccines based on these antigens.

Fasciola hepatica - the pilot study of in vitro assessing immune response against native and recombinant antigens of the fluke.

Fasciola hepatica is a liver fluke that infects 2.4 million of people and causes great economical loss in animal production. To date a 100% effective vaccine has not been developed and the disease is controlled by drug therapy. Great efforts are put into development of effective vaccine against parasite what is difficult since Fasciola spp. (like other helmints) during evolutionary process has developed sophisticated and efficient methods to evade immune response. During preliminary experiments it is convenient to use cell lines which are relatively cheap and allow for reproducible comparison of results between laboratories. We stimulated BOMA (bovine monocyte/macrophage cell line) and BOMAC (bovine macrophage cell line) with native or recombinant antigens of Fasciola hepatica and assessed IFN-γ, IL-4 and TNF-α level upon stimulation. We observed diminished secretion of proinflammatory TNF-α in LPS activated BOMA cells stimulated with Excretory/Secretory products of adult fluke (Fh-ES). We also observed greater changes in gene expression in LPS activated BOMA cells than in non activated BOMA cells upon stimulation using Fh-ES. The results show possibility of using cell lines for in vitro research of bovine immune response against liver fluke, although this model still requires validation and further characterization.

Low T3 syndrome in canine babesiosis associated with increased serum IL-6 concentration and azotaemia

Low triiodothyronine (T3) syndrome, also named euthyroid sick syndrome or non-thyroidal illness syndrome, has been recognized in canine babesiosis caused by Babesia rossi, where it manifested by lowering of the serum thyrotropin (TSH), total thyroxin (TT4) and free thyroxin (FT4) concentrations. This syndrome has also been observed in critical diseases in humans and animals, and the severity of the disease is considered an important factor in lowering of thyroid hormone concentrations. Interleukin-6 (IL-6) plays a role in the development of low T3 syndrome by causing a decrease in deiodinases 1 and 2 activity and increased activity of deiodinase 3, enzymes involved in the conversion of thyroxin (T4) to T3. The purpose of this study was to compare the concentrations of serum thyroid hormones and TSH between healthy dogs and dogs with babesiosis, and to determine correlations between serum IL-6 concentration and serum total T3 (TT3), TT4, FT4, and TSH concentrations, and the level of azotaemia in dogs with babesiosis. The concentrations of IL-6, TT3, TT4, FT4, TSH, urea and creatinine were determined in 13 dogs with canine babesiosis caused by Babesia canis and in 10 healthy dogs. The results of this study showed decreases in TT3, TT4, FT4, and TSH and increases in IL-6, urea and creatinine concentrations in affected dogs in comparison to healthy dogs. The concentration of IL-6 was negatively correlated with TT3 and TSH concentrations and the TT3 concentration was negatively correlated with serum urea and creatinine concentrations. This study showed low T3 syndrome in canine babesiosis, which was confirmed by the determination of the T3 concentration, and demonstrates that in canine babesiosis the T3 concentration is associated with IL-6 concentration.

Excretory/secretory products of Fasciola hepatica but not recombinant phosphoglycerate kinase induce death of human hepatocyte cells

The liver fluke Fasciola hepatica infects a wide range of hosts, and has a considerable impact on the agriculture industry, mainly through infections of sheep and cattle. Further, human infection is now considered of public health importance and is hyperendemic in some regions. The fluke infection causes considerable damage to the hosts’ liver. However, the mechanisms of liver destruction have not yet been completely elucidated. In the present report we incubated a human liver cell line in the presence of either F. hepatica excretory/secretory material (FhES) or recombinant phosphoglycerate kinase (FhPGK). Dosedependent cytotoxicity in the presence of FhES was observed, indicating that FhES is capable of killing human hepatocytes, supporting a role for FhES in damaging host liver cells during infection; while treatment with a recombinant intracellular protein — FhPGK, had no impact on cell survival.

Fas/FasL Pathway Participates in Regulation of Antiviral and Inflammatory Response during Mousepox Infection of Lungs

Fas receptor-Fas ligand (FasL) signalling is involved in apoptosis of immune cells as well as of the virus infected target cells but increasing evidence accumulates on Fas as a mediator of apoptosis-independent processes such as induction of activating and proinflammatory signals. In this study, we examined the role of Fas/FasL pathway in inflammatory and antiviral response in lungs using a mousepox model applied to C57BL6/J, B6. MRL-Faslpr/J, and B6Smn.C3-Faslgld/J mice. Ectromelia virus (ECTV) infection of Fas- and FasL-deficient mice led to increased virus titers in lungs and decreased migration of IFN-γ expressing NK cells, CD4+ T cells, CD8+ T cells, and decreased IL-15 expression. The lungs of ECTV-infected Fas- and FasL-deficient mice showed significant inflammation during later phases of infection accompanied by decreased expression of anti-inflammatory IL-10 and TGF-β1 cytokines and disturbances in CXCL1 and CXCL9 expression. Experiments in vitro demonstrated that ECTV-infected cultures of epithelial cells, but not macrophages, upregulate Fas and FasL and are susceptible to Fas-induced apoptosis. Our study demonstrates that Fas/FasL pathway during ECTV infection of the lungs plays an important role in controlling local inflammatory response and mounting of antiviral response.

Role of Fas/FasL signaling in regulation of anti-viral response during HSV-2 vaginal infection in mice

Fas receptor-Fas ligand (FasL) signaling is involved in apoptosis of virus-infected cells but increasing evidence accumulates on Fas receptor as a mediator of apoptosis-independent processes such as induction of activating and pro-inflammatory signals. In this study, we examined the role of Fas/FasL pathway in regulation of anti-viral response to genital HSV-2 infection using a murine model of HSV-2 infection applied to C57BL6/J, B6. MRL-Faslpr/J and B6Smn.C3-Faslgld/J mice. HSV-2 infection of Fas- and FasL-deficient mice led to decreased migration of IFN-γ expressing NK cells and CD4+ T cells, but not of γδ T cells, into the vaginal tissue. The vaginal tissues of HSV-2 infected Fas- and FasL-deficient mice showed increased production of IL-10, followed by low expression of the early CD69 activation marker on CD4+ and CD8+ T cells and increased numbers of regulatory T cells (Tregs). Experiments in co-cultures of CD4+ T cells and bone marrow derived dendritic cells showed that lack of bilateral Fas-FasL signaling led to expansion of Tregs and increased production of IL-10 and TGF-β1. Our results demonstrate that Fas/FasL can regulate development of tolerogenic dendritic cells and expansion of Tregs early during HSV-2 infection, which further influences effective anti-viral response.

Molecular cloning and expression of the cDNA sequence encoding a novel aspartic protease from Uncinaria stenocephala

Uncinaria stenocephala belongs to Ancylostomatidae family. Members of this family - hookworms - infect millions of people and animals worldwide. U. stenocephala is most pathogenic in dogs and other Canidae, which are the main hosts, and infection causes anemia or even death. So far no effective hookworm vaccine has been developed that is economically viable. Attempts to identify vaccine antigens have led to a group of aspartic proteases, which play a key role in parasite feeding, migration through host tissues and immune evasion. The cDNA of an aspartic protease from U. stenocephala was cloned using the RACE-PCR method. Computational analysis showed that the cDNA encodes a 447 amino acid protein with a molecular mass of 52kDa that shows high homology to aspartic proteases from related hookworms. Analysis identified 1 potential N-glycosylation site, 3 potential disulfide bonds and no O-glycosylation sites. The recombinant protein was expressed in Escherichia coli followed by purification and mouse immunization. Using raised anti-Us-APR-1(2) (Uncinaria stenocephala Aspartic protease-1) serum the presence of Us-APR-1 in the adult stage of U. stenocephala and the expression of homologous protease in L3 and adult stages of A. ceylanicum was confirmed. This analysis is the first phase of work exploring the biological role of Us-APR-1 in parasite-host interactions and raises hope for successful vaccine development against Uncinaria sp. and possibly Ancylostoma sp.

Ancylostoma ceylanicum metalloprotease 6 DNA vaccination induces partial protection against hookworm challenge infection

Hookworms are blood feeding intestinal nematodes that infect more than 500 million people and cause iron deficiency anemia. Infected children suffer from physical and cognitive growth retardation. Because of potential anthelminthic drug resistance, the need for vaccine development is urgent. Numerous antigens have been tested in animal models as vaccines against hookworm infection, but there is no effective human vaccine. We cloned a cDNA encoding Ancylostoma ceylanicum metalloprotease 6 (Acemep-6). Ace-MEP-6 is a protein with a predicted molecular mass of 101.87 kDa and based on computational analysis it is very likely to be engaged in food processing via hemoglobin digestion. Groups of hamsters were immunized with an Ace-mep-6 cDNA vaccine, either once or three times. Animals that were administered one dose developed high resistance (80%, p < 0.01) against challenge infection, whereas triple immunization resulted in no worm burden reduction. These results suggest that DNA vaccines can be powerful tools in ancylostomiasis control, although the mechanisms through which protection is conferred remain unclear.