Ahmet Kursat Azkur

Role of Treg in immune regulation of allergic diseases

Allergy is a Th2‐mediated disease that involves the formation of specific IgE antibodies against innocuous environmental substances. The prevalence of allergic diseases has dramatically increased over the past decades, affecting up to 30% of the population in industrialized countries. The understanding of mechanisms underlying allergic diseases as well as those operating in non‐allergic healthy responses and allergen‐specific immunotherapy has experienced exciting advances over the past 15 years. Studies in healthy non‐atopic individuals and several clinical trials of allergen‐specific immunotherapy have demonstrated that the induction of a tolerant state in peripheral T cells represent a key step in healthy immune responses to allergens. Both naturally occurring thymus‐derived CD4+CD25+FOXP3+ Treg and inducible type 1 Treg inhibit the development of allergy via several mechanisms, including suppression of other effector Th1, Th2, Th17 cells; suppression of eosinophils, mast cells and basophils; Ab isotype change from IgE to IgG4; suppression of inflammatory DC; and suppression of inflammatory cell migration to tissues. The identification of the molecules involved in these processes will contribute to the development of more efficient and safer treatment modalities.

Crimean-Congo hemorrhagic fever virus: genetic analysis and tick survey in Turkey.

ABSTRACT Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne virus in the family Bunyaviridae, genus Nairovirus. The virus is transmitted to humans through infected tick bites or from direct contact with viremic animals or humans. In the present study, a total of 1,015 adult ticks were collected from cattle (603 specimens), sheep (17 specimens), and goats (395 specimens) in the Kelkit Valley in Turkey. Four tick species were recognized on the animals in the surveyed region. The most abundant species were Rhipicephalus bursa and Hyalomma marginatum marginatum, at 47.68% (484/1,015) and 46.40% (471/1,015), respectively. Reverse transcriptase PCR was used to recover partial sequences of the CCHFV small (S) genome segment. The presence of CCHFV was determined in 3 of 33 (9.09%) R. bursa pools and in 1 of 31 (3.22%) H. m. marginatum pools. Virus sequences from R. bursa were extremely different from those of the Greek CCHFV strain (U04958) isolated from an R. bursa tick. Phylogenetic analysis indicated that the CCHFV isolates obtained in this study clustered in group 5, whose range encompasses southwestern Russian and Kosovo. This is the first evidence of CCHFV in ticks from Turkey. Even though Hyalomma is the main vector for CCHFV, R. bursa may play a role in CCHFV transmission.

A Large-Scale Outbreak of Bovine Ephemeral Fever in Turkey, 2012

ABSTRACT Regional cases of bovine ephemeral fever (BEF) were documented previously in Turkey. Previous cases were confirmed in South-East Turkey with low cow mortality. Recent BEF-suspected outbreaks with high mortality were documented in many regions of Turkey in 2012. The aim of study was the epidemiological examination of the outbreak and molecular characterization of the viruses detected from the outbreak. For this reason, blood samples were collected from BEF-suspected outbreak regions. From the results of RT-PCR, high rate of BEF-suspected samples (48/60 or 80%) was found positive for BEF virus (BEFV) RNA. The nucleotide sequences of the G1 region of G gene of BEFV in the current study during the 2012 outbreak were grouped into cluster II of BEFV. It was suggested that BEFV may be spread out to other neighbor countries in the future years.

Epidemiology and genetic characterization of BVDV, BHV-1, BHV-4, BHV-5 and Brucella spp. infections in cattle in Turkey

The aim of the study was to determine the epidemiological data of bovine viral diarrhea virus (BVDV), bovine herpesvirus-1 (BHV-1), bovine herpesvirus-4 (BHV-4), bovine herpesvirus-5 (BHV-5) and Brucella–associated cattle that were previously reported to have abortion and infertility problems in Ankara, Corum, Kirikkale and Yozgat provinces, Turkey. Whole blood and sera samples were obtained from 656 cattle, and antibodies against Brucella spp. were detected in 45 (6.86%) and 41 (6.25%) animals by Rose Bengal plate and serum tube agglutination tests, respectively. The seropositivity rates against BVDV, BHV-1 and BHV-4 were 70.89%, 41.3% and 28.78%, respectively. RT-PCR and PCR were performed to detect RNA and DNA viruses in blood samples, respectively. The BVDV 5′-untranslated region and BHV-1 gB gene detected in this study were phylogenetically analyzed. The BVDV strains analyzed in this study were closely related to those previously reported from Turkey. The nucleotide sequence from the BHV-1 strain detected in this study is the first nucleotide sequence of BHV-1 circulating in this area of Turkey deposited in the GenBank. The presence of Brucella spp. and prevalence of BHV-1, BHV-4 and BVDV in cattle should be further investigated throughout these regions.

Role of NETs in the difference in host susceptibility to Toxoplasma gondii between sheep and cattle

The main aim of this study was to compare extracellular traps (NETs) formation by polymorphonuclear neutrophils (PMNs) of cattle and sheep when exposed to T. gondii tachyzoites in vitro. The effects of parasite concentrations and different incubation periods on NETs development in cattle and sheep PMNs were studied. The effect of NET structures on host cell invasion by tachyzoites was also studied. This is the first report of NETs development by sheep and cattle PMNs against T. gondii in vitro. T. gondii-induced extracellular DNA production from PMNs was dependent on tachyzoite concentrations and incubation time in both sheep and cattle. Many nuclear and cytoplasmic changes were observed in sheep and cattle PMNs after exposure to T. gondii tachyzoites. The typical appearance of NETs, with MPO, NE and histone (H3) attached to extracellular DNA, was observed. Tachyzoites were entrapped within this structure. Myeloperoxidase (MPO) activity was higher in the cattle PMN-tachyzoite co-cultures than sheep. NETs structures released from sheep PMNs caused mechanical immobilisation of T. gondii tachyzoites, however, NET structures released from cattle PMNs may be lethal to tachyzoites. Bovine MPO may have a lethal effect on T. gondii tachyzoites in vitro during a 3h incubation. Besides other mechanisms that effect on host susceptibility to T. gondii in sheep and cattle, extracellular traps formation as a part of immunological reactions may be play a role in host susceptibility to T. gondii.

Comparison of hematological and biochemical parameters in sheep naturally and persistently infected with a border disease virus

In this study, we investigated the changes occurring in the activities of determining the biochemical and hematological parameters in persistently infected sheep with border disease virus (BDV) and control sheep. While cholesterol, aspartate aminotransferase, lactate dehydrogenase, high-density lipoprotein, and glucose parameters were found to be statistically different between control and BDV positive groups (p < 0.01), total protein, alkaline phosphotase, creatine kinase, amylase, glucose, and high-density lipoprotein were found to be statistically different between control and persistently infected group (p < 0.01). Interestingly, all groups were shown only mean corpuscular volume parameter was different (p < 0.01). It was found that cholesterol, aspartate aminotransferase, amylase, high-density lipoprotein, and low-density lipoprotein parameters were different between PI and infected sheep (p < 0.01). It was speculated that BDV might effect also the expression of low-density lipoprotein receptor and determination of the changes in BD and its clinical importance might contribute to the veterinarians and scientists studying in this area.

A study of the chikungunya virus in humans in Turkey

Background/aim: The chikungunya virus (CHIKV) is a mosquito-borne disease and has recently been causing explosive outbreaks. The CHIKV has spread throughout all continents. Although the first chikungunya case imported from India to Turkey was reported in 2012, there is no detailed epidemiologic study in Turkey yet. The aim of this study was to investigate the seroprevalence of the CHIKV in Turkey. Materials and methods: ELISA was used to screen 500 random serum samples of healthy people collected from Kırıkkale, which is located in central Anatolia in Turkey. The results were verified by indirect immunofluorescence test (IIFT). Results: The results showed that 0.4% samples were positive for CHIKV. In the verification study with IIFT, CHIKV IgG type antibodies were defined as negative. To the best of our knowledge, this is the first serological study on the CHIKV in Turkey. Conclusion: Further studies are needed to elucidate the epidemiological situation in patients that have fever and arthritis.

Complete genome analysis of highly pathogenic bovine ephemeral fever virus isolated in Turkey in 2012

Relatively high prevalence and mortality rates of bovine ephemeral fever (BEF) have been reported in recent epidemics in some countries, including Turkey, when compared with previous outbreaks. A limited number of complete genome sequences of BEF virus (BEFV) are available in the GenBank Database. In this study, the complete genome of highly pathogenic BEFV isolated during an outbreak in Turkey in 2012 was analyzed for genetic characterization. The complete genome of the Turkish BEFV isolate was amplified by reverse transcription-polymerase chain reaction (RT-PCR) and sequenced. It was found that the complete genome of the Turkish BEFV isolate was 14,901 nt in length. The complete genome sequence obtained from the study showed 91-92% identity at nucleotide level to Australian (BB7721) and Chinese (Bovine/China/Henan1/2012) BEFV isolates. Phylogenetic analysis of the glycoprotein gene of the Turkish BEFV isolate also showed that Turkish isolates were closely related to Israeli isolates. Because of the limited number of complete BEFV genome sequences, the results from this study will be useful for understanding the global molecular epidemiology and geodynamics of BEF.

Haematological parameters in blood of maedi-visna virus-infected and uninfected sheep

The maedi-visna virus (MVV) classified as a lentivirus of the retroviridae family, causes a very common economically important disease in sheep, in many parts of the worlds. Presences of the infection in Turkey have been shown by researches in previous studies. In this study all blood samples were examined by ELISA and PCR to detect MVV antibody and antigen responses, respectively. Hematological findings were monitored and comparing antibody and antigen positive naturally infected (n= 5), antibody positive and antigen negative (n=20), antibody and antigen negative (n=20) in sheep was done. When infected sheep were compared with control sheep, Hgb and MPV parameters were shown statistically different (P�0.001). These findings suggested that MVV infections should be considered as an important health risk for sheep flock and Hgb and MPV blood parameters may be helpful to diagnosis of MVV.