• 한국가금학회지
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• 제26권3호
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• pp.149-170
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• 1999

Protozoa of the genus Eimeria are the etiologic agents of avian coccidiosis, the most economically important Parasitic disease for the poultry industry. Coccidia multiply in intestinal epithelial cells of a wide range of hosts, including livestock in addition to poultry. Chemotherapy is extensively used to control coccidiosis. However, development of drug resistance by Eimeria parasites, the intensive cost and labor involved in the identification of new anticoccidial compounds and public awareness of drug residues in foods warrant alternative methods to prevent coccidiocic in the fast growing poultry industry. For these reasons, there is a great interest in developing vaccines against avian coccidiosis. Live Eimeria vaccines confer protective immunity, however a significant disadvantage of using these types of vaccines is their pathogenicity. Live parasites with attenuated pathogenicity also usually produce immunity but may revert back to a pathogenic form and may be contaminated with other pathogenic organisms. Killed Eimeria vaccines are safer but, unlike live attenuated vaccines, are not able to generate cytotoxic T lymphocyte responses. Recombinant vaccines are biochemically purified proteins produced by genetic engineering that consist of particular epitopes or metabolites of Eimeria. Unlike live attenuated organisms, recombinant vaccines do not possess as much risk and generally are able to induce both humoral and cell mediated immunity. DNA vaccines consist of genes encoding immunogenic proteins of pathogens that are directly administered into the host in a manner that the gene is expressed and the resulting protein generates a protective immune response. Although all of these different types of vaccines have been applied to coccidiosis, this disease continues to cause substantial morbidity and mortality in the poultry industry. Future development of an effective vaccine against coccidiosis will depend on further investigation of protective immunity to Eimeria infection and identification of important immundgenic parasite molecules.

• 한국가금학회지
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• 제20권1호
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• pp.17-31
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• 1993

Several aspects about the epidemiological status of chicken coccidiosis, its control measures and recent research activities in Korea are discussed in this paper. Medication with different available anticoccidial drugs has been reasonably effective in treating and preventing serious outbreaks of coccidiosis in chicken, but the disease remains one of the most expensive and common diseases of popultry production in this country, and more recently its incidence is increasing, possibly due to the more intensive methods of husbandry and the immergence of resistant strains of coccidia. Therefore, this necessitates a continuous search for new methods such as medication program (shuttl and rotation program) and immunization using attenuated strains or parasite antigens.

• 한국가금학회지
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• 제26권2호
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• pp.131-144
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• 1999

Coccidiosis, an intestinal infection caused by intracellular protozoan parasites belonging to several different species of Eimeria seriously impairs the growth and feed utilization of livestock and poultry. Due to complex life cycle of organism and intricate host immune responses to Elmeria, coccidia vaccine development has been difficult. Understanding of basic imunobiology of pertinent host-parasite interactions is necessary for the development of novel control strategy. Although chickens infected with Eimeria spp. produce parasite-specific antibodies in both the circulation and mucosal secretions, antibody mediated responses play a minor role in protection gainst coccidiosis. Rather, increasing evidence show that cell-mediated immunity plays a major role in resistance to coccidiosis. T-lymphocytes appear to respond to coccidiosis both through cytokine production and a direct cytotoxic attack on infected cells. The exact mechanisms by which T-cells eliminate the parasites, however, remain to be investigated. Since it is crucial to understand the intestinal immune system in order to develop an immunological control strategy against any intestinal immune system in order to develop an immunological control strategy against any intestinal diseases, this presentation will summarize our current understanding of the avian intestinal immune system and mucosal immune responses to Eimeria, to provide a conceptual overview of the complex molecular and cellular events involved in intestinal immune responses to enteric pathogens.

• Parasites, Hosts and Diseases
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• 제51권2호
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• pp.147-154
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• 2013

To control coccidiosis without using prophylactic medications, a DNA vaccine targeting the gametophyte antigen Gam56 from Eimeria maxima in chickens was constructed, and the immunogenicity and protective effects were evaluated. The ORF of Gam56 gene was cloned into an eukaryotic expression vector pcDNA3.1(zeo)+. Expression of Gam56 protein in COS-7 cells transfected with recombinant plasmid pcDNA-Gam56 was confirmed by indirect immunofluorescence assay. The DNA vaccine was injected intramuscularly to yellow feathered broilers of 1-week old at 3 dosages (25, 50, and $100{\mu}g/chick$). Injection was repeated once 1 week later. One week after the second injection, birds were challenged orally with $5{\times}10^4$ sporulated oocysts of E. maxima, then weighed and killed at day 8 post challenge. Blood samples were collected and examined for specific peripheral blood lymphocyte proliferation activity and serum antibody levels. Compared with control groups, the administration of pcDNA-Gam56 vaccine markedly increased the lymphocyte proliferation activity (P<0.05) at day 7 and 14 after the first immunization. The level of lymphocyte proliferation started to decrease on day 21 after the first immunization. A similar trend was seen in specific antibody levels. Among the 3 pcDNA-Gam56 immunized groups, the median dosage group displayed the highest lymphocyte proliferation and antibody levels (P<0.05). The median dosage group had the greatest relative body weight gain (89.7%), and the greatest oocyst shedding reduction (53.7%). These results indicate that median dosage of DNA vaccine had good immunogenicity and immune protection effects, and may be used in field applications for coccidiosis control.

• 한국가금학회지
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• 제34권1호
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• pp.77-83
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• 2007

Poultry products including meat and eggs constitute a major protein source in the American diet and disease-causing pathogens represent major challenges to the poultry industry. More than 95% of pathogens enter the host through the mucosal surfaces of the respiratory, digestive and reproductive tracts and over the past few decades, the two main mechanisms used to control diseases have been the use of vaccines and antibiotics. However, in the poultry industry, there are mounting concerns over the ability of current vaccines to adequately protect against emerging hyper-virulent strains of pathogens and a lack of suitable, cost effective adjuvants. Thorough investigation of the immunogenetic responses involved in host-pathogen interactions will lead to the development of new and effective strategies for improving poultry health, food safety and the economic viability of the US poultry industry. In this paper, I describe the development of immunogenomic and proteomic tools to fundamentally determine and characterize the immunological mechanisms of the avian host to economically significant mucosal pathogens such as Eimeria. Recent completion of poultry genome sequencing and the development of several tissue-specific cDNA libraries in chickens are facilitating the rapid application of functional immunogenomics in the poultry disease research. Furthermore, research involving functional genomics, immunology and bioinformatics is providing novel insights into the processes of disease and immunity to microbial pathogens at mucosal surfaces. In this presentation, a new strategy of global gene expression using avian macrophage (AMM) to characterize the multiple pathways related to the variable immune responses of the host to Eimeria is described. This functional immunogenomics approach will increase current understanding of how mucosal immunity to infectious agents operates, and how it may be enhanced to enable the rational development of new and effective strategies against coccidiosis and other mucosal pathogens.

• 대한수의학회지
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• 제38권1호
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• pp.129-132
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• 1998

Avian coccidiosis is a very important disease of poultry industry. In recent years, many researchers studied for the immunology of avian coccidiosis. Coccidial vaccines have been used at some poultry farms in many countries. In order to evaluate the anticoccidial effects of coccidial vaccine to chicken treated with anticoccidial drugs, 4 week-old chicken were administered anticoccidial drugs and challenged with avian coccidia at 2 weeks after vaccination of coccidia. The body weight gains, lesion scores, oocyst indices and anticoccidial indices of chicken were investigated at the time of vaccination, challenge and necropsy. The body weight gains and feed conversion rates of groups immunized with coccidial vaccine and treated with anticoccidial drugs were moderately higher and lower than those of groups treated with anticoccidial drugs, respectively. The lesion score and oocyst indices of all groups immunized with coccidial vaccine and/or treated with anticoccidial drugs were milder than those of infected control groups. The anticoccidial indices of groups immunized with coccidial vaccine and treated with anticoccidial drugs were moderately higher and lower than those of groups. treated with anticoccidial drugs. But all of the investigated items were not statistically significant.

• 한국가금학회지
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• 제38권4호
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• pp.275-284
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• 2011

As the world population grows and developing countries become more affluent, the global consumption of meat will increase by more than 50% within the next 10 years. Confronting the increased demand for poultry food products are emerging field diseases, increasing regulatory bans of antimicrobial growth promoters, high-density growth conditions, and waste management. Although biotechnology offers solutions to some of these challenges, basic studies are needed to better understand the complex interaction between the intestinal microbiome, host immunity and the environment. This presentation will focus on emerging strategies to enhance gut immunity and to decrease economic losses due to poultry diseases. This presentation will highlight recent developments in coccidiosis research and provide information on host immunity, immunomodulation, and the latest advances in dietary and nutritional approaches against coccidiosis. Such information will magnify our understanding of host-parasite biology, mucosal immunology, and design of future nutritional interventions and vaccination strategies for coccidiosis.

• 한국임상수의학회지
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• 제12권1호
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• pp.911-916
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• 1995

Ionophorous antibiotics have been used popularly for the protection of avian coccidiosis, though Halo-fuginone which is derived from an extract of the Dichroa febrifuga, was developed as an antimalarial and anticoccidial agent. The antibiotics are regarded as the causes of residues in the avian products, therefore the author has tried to find out more safe herbal materials for the control of avian coccidiosis. Thus, the extracts of 5 kinds of herbs, roots of Pulsatilla koreana Nakai and Sophora flavescens Aiton, nuts of Quisqualis indica Linne, whole herbs of Artemisia annua Linne and Polygonum aviculare Linne, were investigated on the efficacy against E tenella. Survival rates, bloody diarrhea, lesion scores, body-weight gains and feed conversion rate were investigated at the 1st and the 2nd week after infection. The bloody diarrhea in the groups treated with P koreana, A annua, Q indica and P aviculare were milder than those in the groups treated with S flavescens and infected control. The lesion score in the groups treat.4 with herb extracts(2.00$\pm$0.82~2.65$\pm$0.89) were lower than those in the control group (2.80$\pm$0.7l). But, there was not significant in all infected groups. The body weight gai in the groups treated with P koreana, S flavescens, A annua and Q indica(291.74$\pm$15.76~303.43$\pm$51.90) were higher than that in the control group (283.71$\pm$16.53) but there was not significant. In a conclusion, analyzing the data of the survival rates, bloody diarrheal symptoms, lesion scores, body weight gains and oocyst excretions, the extract of S flavescens, P koreana, A annua and Q indica were effective. The further research on the above herbal materials will have been carried out by the author and the other researchers by means of the chemical analysis of the components.

• 한국가금학회지
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• 제19권3호
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• pp.151-160
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• 1992

현재 콕시듐 병의 방제는 약제 투여, 사육관리, 백신을 이용하거나 혹은 이들 방법을 적당히 혼합하여 실시하고 있다. 약제 투여 방법은 약의 내성이라는 문제점을 내재하고 있지만 아직도 콕시듐 방제에 최우선 방법으로 쓰고 있으며 이러한 약제 내성을 조금이나마 지연시키기 위하여 shuttle, 혹은 rotation program을 쓰고 있다. 따라서 약제 내성 검사는 각 농장에 어떠한 약제가 효과가 있는지를 알아보는데 가장 중요한 방법이 되어 왔던 것이다. 콕시듐 방제에 있어서 사육관리에 의한 방법은 아직은 완전한 효과적인 방법으로 정착되지 않았는데 그 이우는 소독제만으로는 콕시듐의 원충을 죽일 수 없기 때문이다. 백신에 의한 방법은 현재까지 살아있는 콕시듐 원충을 제한적으로 쓰고 있는 단계이다. 새로운 형태의 백신개발이 요즈음 연구가 되고 있는데 이 백신은 순화시킨 콕시듐 원충을 사용하거나 유전공학적 방법 혹은 원충의 일부분에 대한 항원을 추출하여 백신으로 이용하는 것이다.

• 한국가금학회지
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• 제38권4호
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• pp.323-330
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• 2011

닭의 단일 클론 항체인 13C8 항체는 조류의 콕시듐증을 유발하는 것으로 알려진 Eimeria acervulina의 포자충(sporozoites) 항원에 결합하는 닭 항체이다. 그러나 닭 하이브리도마 유전자의 불안정성 때문에 분비되는 항체의 생산량이 낮은 단점이 있다. 이러한 단점을 보완하기 위해 hybridoma로 부터 항체의 중사슬 가변 부위(VH)유전자와 경사슬 가변 부위(VL) 유전자를 증폭하여 linker peptide로 연결해준 재조합 ScFv 항체 유전자를 구축하고, E. coli를 형질 전환시켜 재조합 단백질로 발현 정제하였다. ELISA 분석 결과 재조합 13C8 ScFv 항체는 세 종류의 Eimeria spp.에 대해 모두 항원 결합력을 나타내었으며, 염기서열 분석을 수행하여 germline sequence와 비교한 결과 닭 항체유전자의 다양성(diversity)은 pseudogene들의 gene conversion 기작에 의해 이루어짐을 제시해 주었다.