• 한국가금학회지
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• 제35권1호
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• pp.85-99
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• 2008

국내 육계 농장에서 avian reovirus의 감염 여부를 확인하기 위한 ELISA 검사법을 이용한 혈청 검사와 바이러스 분리 및 2개 농장에서 분리된 바이러스를 SPF 닭에 공격 접종하여 병원성을 확인한 결과, 다음과 같은 결론을 얻었다. 1. 1일령 육계 병아리에서 avian reovirus에 대한 모체이행 항체 역가 검사를 통하여 육용종계에서 avian reovirus에 대한 항체 보유 상태가 매우 다양하며, 이로 인해 후 대 병아리의 항체 수준도 매우 불균일하게 분포된다는 것을 알 수 있었다. 2. 육계에서 avian reovirus에 대한 모체 이행 항체 역가는 14일령 전에 대부분 소실되며, 그 이후 혈청 역가가 상승하는 것이 확인되어 국내 육계 농장에서도 avian reovirus가 감염이 되는 것을 확인할 수 있었으며, 각 농장의 감염 상황 및 계군의 면역 정도에 따라 혈청 역가가 다양하게 분포함을 알 수 있었다. 3. RT-PCR을 이용한 avian reovirus 확인 결과, 1일령 병아리에서 모두 음성으로 확인되었고, 14일령과 출하 일령에 2개 농장에서 양성으로 나타나, 국내 육계 농장에서 avian reovirus 감염은 주로 14일령 이후에 나타나는 것으로 판단되었다. 4. 본 실험에서 실시한 ELISA, RT-PCR, 전자현미경 관찰을 통하여 국내 육계 농가에서의 ARV 감염과 존재를 확인할 수 있었다. 그러나 검사 방법간의 결과가 불일치한 것은 avian reovirus의 분리가 감염된 농장의 상황, 닭의 감염 일령 및 분리 장기에 따라 차이가 있음을 알 수 있었다. 5. 9일령 SPF 부화란 접종을 통해 2개의 육계 농장에서 avian reovirus가 분리되었고 분리된 바이러스를 3주령 SPF 닭에 공격 접종 시 혈청 역가의 상승 및 주요 조직에서 바이러스가 확인되었으나, 특이적인 임상 증상은 관찰되지 않았다. 이는 닭의 연령에 따라 avian reovirus에 저항성이 있는 것으로 여겨지며 ARV의 조직 내 잔존은 감염 장기에 따라 다르다는 것을 알 수 있었다.

• Parasites, Hosts and Diseases
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• 제54권6호
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• pp.797-801
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• 2016

Heishui county, located in northwest Sichuan province, southwestern China, is an endemic area of zoonotic visceral leishmaniasis (VL) and is the most intractable area. VL is never destroyed in it. Asymptomatic dogs (Leishmania parasites have been diagnosed but clinically healthy) are considered to be a potential reservoir host in zoonotic VL area, and most can lead to infection of individuals, that is a new challenge for controlling VL in humans. The present study aimed to assess the Leishmania infection rate of asymptomatic dogs in Heishui county. Total 105 asymptomatic domestic dogs were gathered from 4 districts in Heishui county to investigate the infection rate with serological and molecular methods based on ELISA and kinetoplast minicircle DNA(kDNA) PCR, respectively. Out of 105 dogs, 44 (41.9%) were positive by more than 1 method; 21 (20.0%) were positive by ELISA, and 30 (28.6%) were positive by kDNA-PCR. Our study showed that Leishmania infection of domestic dogs which is clinically healthy is prevalent in the studied district, and the asymptomatic dogs infected by Leishmania may be the primary reason for the prevalence of visceral leishmaniasis in the area.

• Journal of Microbiology and Biotechnology
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• 제31권8호
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• pp.1088-1097
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• 2021

Grouper nervous necrosis virus (GNNV) infection causes mass grouper mortality, leading to substantial economic loss in Taiwan. Traditional methods of controlling GNNV infections involve the challenge of controlling disinfectant doses; low doses are ineffective, whereas high doses may cause environmental damage. Identifying potential methods to safely control GNNV infection to prevent viral outbreaks is essential. We engineered a virus-binding bacterium expressing a myxovirus resistance (Mx) protein on its surface for GNNV removal from phosphate-buffered saline (PBS), thus increasing the survival of grouper fin (GF-1) cells. We fused the grouper Mx protein (which recognizes and binds to the coat protein of GNNV) to the C-terminus of outer membrane lipoprotein A (lpp-Mx) and to the N-terminus of a bacterial autotransporter adhesin (Mx-AIDA); these constructs were expressed on the surfaces of Escherichia coli BL21 (BL21/lpp-Mx and BL21/Mx-AIDA). We examined bacterial surface expression capacity and GNNV binding activity through enzyme-linked immunosorbent assay; we also evaluated the GNNV removal efficacy of the bacteria and viral cytotoxicity after bacterial adsorption treatment. Although both constructs were successfully expressed, only BL21/lpp-Mx exhibited GNNV binding activity; BL21/lpp-Mx cells removed GNNV and protected GF-1 cells from GNNV infection more efficiently. Moreover, salinity affected the GNNV removal efficacy of BL21/lpp-Mx. Thus, our GNNV-binding bacterium is an efficient microparticle for removing GNNV from 10‰ brackish water and for preventing GNNV infection in groupers.

• IMMUNE NETWORK
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• 제22권5호
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• pp.41.1-41.16
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• 2022

The human antimicrobial peptide LL-37 has chemotactic and modulatory activities in various immune cells, including dendritic cells. Because of its characteristics, LL-37 can be considered an adjuvant for vaccine development. In this study, we confirmed the possible adjuvant activity of LL-37 in mucosal vaccine development against Middle East respiratory syndrome-coronavirus (MERS-CoV) by means of intranasal immunization in C57BL/6 and human dipeptidyl peptidase 4 (hDPP4)-transgenic (hDPP4-Tg) mice. Intranasal immunization using the receptor-binding domain (RBD) of MERS-CoV spike protein (S-RBD) recombined with LL-37 (S-RBD-LL-37) induced an efficient mucosal IgA and systemic IgG response with virus-neutralizing activity, compared with S-RBD. Ag-specific CTL stimulation was also efficiently induced in the lungs of mice that had been intranasally immunized with S-RBD-LL-37, compared with S-RBD. Importantly, intranasal immunization of hDPP4-Tg mice with S-RBD-LL-37 led to reduced immune cell infiltration into the lungs after infection with MERS-CoV. Finally, intranasal immunization of hDPP4-Tg mice with S-RBD-LL-37 led to enhanced protective efficacy, with increased survival and reduced body weight loss after challenge infection with MERS-CoV. Collectively, these results suggest that S-RBD-LL-37 is an effective intranasal vaccine candidate molecule against MERS-CoV infection.

• The Plant Pathology Journal
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• 제21권3호
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• pp.237-243
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• 2005

Resistance inductions on the leaves of cucumber plant by an arbuscular mycorrhiza Glomus intraradices were investigated. In addition, the infection structures were observed at the penetration sites on the leaves of plant inoculated with Colletotrichum orbiculare using a fluorescence microscope. The severity of anthracnose disease caused by Colletotrichum orbiculare was significantly decreased on the leaves of cucumber plant colonized with G intraradices compared with those of non-treated control plants. As a positive control, pre-treatment with DL-3-aminobutyric acid (BABA) caused a remarkable reduction of the disease severity on the pathogen-inoculated leaves. There were no significant differences in the frequency of either germination or appressorium formation of the plant pathogen between mycorrhiza colonized and non-treated plants. It was also the same on the BABA pre-treated plants. However, the frequency of callose formation was significantly high on the leaves of G intraradices colonized plants compared to those of non-treated control plants at 5 days after challenge inoculation. On the leaves of BABA treated plants callose formation was not significantly high than those of non-treated, although the disease severity was more strongly suppressed. It was suggested that the resistance induced by colonization with G. intraradices might be related to the enhancement of callose formation at the penetrate sites on the leaves invaded by the pathogen, whereas resistance by BABA did not.

• 한국어병학회지
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• 제29권1호
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• pp.13-23
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• 2016

Lectins play significant roles in the innate immune responses through binding to pathogen-associated molecular patterns (PAMPs) on the surfaces of microorganisms. In the present study, tissue distribution and expression analysis of olive flounder lectins were performed after viral hemorrhagic septicemia virus (VHSV) challenge. Fish egg lectin and serum lectin were found to be predominantly expressed in the gills and liver, these results indicate that the transcript expression of olive flounder lectins is concentrated in immune-related tissues. Following a VHSV challenge, an overall increase in the transcript levels of the genes was observed and the expression patterns were distinctly divided into early and later responses during VHSV infection. In conclusion, olive flounder lectins are specifically expressed in immune-related organs and induced in both the immediate and long-lasting immune responses to VHSV in the olive flounder. These results indicate that lectins may be play important roles in the host defense mechanism and involved in the innate and adaptive immune response to viruses in fish.

• 한국동물위생학회지
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• 제32권1호
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• pp.77-82
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• 2009

Salmonella (S.) Typhimurium infection in pigs is a major source of human foodborne salmonellosis. Recently, the swine industry in Korea has been suffered from salmonellosis causing severe economic loss to farms. Organic acids have antibacterial activity which prevents bacteria from multiplying by reducing the pH in the gastrointestinal tract. The aim of the present study is to evaluate whether $Salstop^{(R)}$ mixed with organic acids is able to have influence on growth performance and whether it prevents against S. Typhimurium in weaning pigs. Four experimental treatments were examined: general diet added with 0.3% of $Salstop^{(R)}$ after S. Typhimurium ($1.0{\times}10^{10}CFU/ml$) challenge, group A; commercial feed after Salmonella ($1.0{\times}10^{10}CFU/ml$) challenge, group B; commercial feed and $Salstop^{(R)}$, group C; commercial feed, Group D. At the end of the study, no significant differences in daily body weight gain and feed intake were observed between groups treated with $Salstop^{(R)}$ and groups treated without, whereas feed conversion ratio (FCR) tended to be improved in groups treated with $Salstop^{(R)}$ between days 1 to 14. Serological and microbiological evolution of the infection were examined by ELISA and microbiological culture from serums and fecal samples, respectively. In groups that challenged by S. Typhimuriums, the group without $Salstop^{(R)}$ showed higher prevalence and bacterial shedding compared to the groups treated with $Salstop^{(R)}$. Our results suggest that the administration of $Salstop^{(R)}$ could be used to promote feed efficiency and to reduce the prevalence of salmonellosis in weaners.

• Journal of Microbiology and Biotechnology
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• 제29권3호
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• pp.489-499
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• 2019

Subunit vaccines are safer and more stable than live vaccines although they have the disadvantage of eliciting poor immune response. To develop a subunit vaccine, an effective delivery system targeting the key elements of the protective immune response is a prerequisite. In this study, oxidized carbon nanospheres (OCNs) were used as a subunit vaccine delivery system and tuberculosis (TB) was chosen as a model disease. TB is among the deadliest infectious diseases worldwide and an effective vaccine is urgently needed. The ability of OCNs to deliver recombinant Mycobacterium tuberculosis (Mtb) proteins, Ag85B and HspX, into bone marrow derived macrophages (BMDMs) and dendritic cells (BMDCs) was investigated. For immunization, OCNs were mixed with the two TB antigens as well as the adjuvant monophosphoryl lipid A (MPL). The protective efficacy was analyzed in vaccinated mice by aerosol Mtb challenge with a virulent strain of Mtb and the bacterial burdens were measured. The results showed that OCNs are highly effective in delivering Mtb proteins into the cytosol of BMDMs and BMDCs. Upon immunization, this vaccine formula induced robust Th1 immune response characterized by cytokine profiles from restimulated splenocytes and specific antibody titer. More importantly, enhanced cytotoxic $CD8^+$ T cell activation was observed. However, it did not reduce the bacteria burden in the lung and spleen from the aerosol Mtb challenge. Taken together, OCNs are highly effective in delivering subunit protein vaccine and induce robust Th1 and $CD8^+$ T cell response. This vaccine delivery system is suitable for application in settings where cell-mediated immune response is needed.

• 대한미생물학회지
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• 제21권4호
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• pp.423-434
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• 1986

The role of macrophages in the resistance of ICR mice to Candida albicans and Salmonella typhimurium was assessed using silica, agent which selectively inactivates macrophages or poly-2-vinylpyridine-N-oxide(PVNO), a lysosomal stabilizing agent. In addition, effect of silica on humoral and cellular immune responses to sheep red blood cells(SRBC) or polyvinylpyroridone(PVP) was examind. Colonyforming units(CFU) of C. albicans or S. typhimurium in the spleen, livers and kidneys of silica-treated or diluent-treated mice were enumerated at various times after infection. Silica was given i. v. to mice at 4 days or 1 day before infection. Although there was no apparent differences in the number of CFU of C. albicans cultured from the spleens or livers of silica-treated and control mice at every assay period, significant differences in the number of CFU of C. albicans in the kidneys of silica-treated and control mice. Namely, silica given to mice 1 day before infection significantly increased the number of CFU of C. albicans in the kidneys at 2, 4 and 6 days after infection, but did not change the number of CFU at 8 days after infection. Silica given to mice at 4 days before infection significantly increased the number CFU in the kidneys at 2 and 4 days after infection, but rather decreased the number of CFU at 8 days after infection. The number of CFU of C. albians cultured from the kidneys of splenectomized which were experimentally infected mice was similar to the number recovered from sham-operated mice at 4 and 8 days postinfection irrespective of time of infection relative to operation. The pretreatment of mice with PVNO appeared to abrogate the silica-induced susceptibility of mice to C. albicans. PVNO alone showed somewhat protective effect against challenge with C. albicans. In contrast, silica treatment did not alter the number of CFU of S. typhimurium recovered from the spleens and kidneys of mice. The administration of silica to mice at 4 days or 1 day before SRBC immunization significantly suppressed delayed-type hypersensitivity(DTH) reactions to SRBC and antibody production to SRBC, a thymus-dependent antigen and PVP, a thymus-independent antigen. These results provide evidence that macrophages play an important role in susceptibility to Candida infection and strongly demonstrated that macrophages play an essential role in the induction of immune responses in mice.

• 생명과학회지
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• 제20권8호
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• pp.1181-1185
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• 2010

본 연구는 WSSV의 주요 구조단백질인 VP19와 VP28을 모두 포함하는 VP19+28 fusion protein을 제조하여, Litopenaeus vannamei에서 WSSV에 대한 백신으로서의 효능을 평가하고자 수행하였다. VP19와 VP28 유전자를 fusion하여 제작한 VP19+28 유전자를 pET-28a(+) vector에 삽입하고 단일단백질로서 제작된 VP19+28 유전자를 E. coli BL21 (DE3)에서 발현시켰다. 백신실험을 위해 새우에게 2주 동안 실험용 사료를 급이하였으며, 그 후 바이러스액($1{\times}10^2$배로 희석한 WSSV)을 이용하여 새우에게 주사 감염에 의해 in vivo 공격실험(challenge test)을 수행하였다. 실험결과, vaccination을 하지 않은 새우들은 감염 후 11일째에 100%의 누적폐사율을 보였으며, host control로써 E. coli BL21을 사용하여 vaccination한 새우들은 감염 후 17일째에 100%의 누적폐사율을 보였다. rVP19, rVP28, rVP19+28을 이용하여 vaccination한 새우들의 경우 감염 후 21일째에 각각 66.7%, 41.7%, 41.7%의 누적폐사율을 보였다. 이상의 결과를 통해 rVP28과 rVP19+28이 WSSV에 대해 높은 백신효능을 가짐을 확인하였다. 또한 감염 후 21일째에 fusion protein rVP19+28과 rVP28의 누적폐사율은 동일하였지만 공격실험기간 동안 폐사율이 rVP19+28을 투여 한 실험군이 낮게 나타나는 것을 보아 WSSV에 대한 새우의 방어효능은 rVP19+28이 더 높음을 나타내는 것이다.