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Effect on Milk Quality, Causative Agents and Control
Fox, Laurence K.,Bohach, Gregory A.,Lee, Sang-Un,Park, Kun-Taek,Park, Yong-Ho 한국수의공중보건학회 2003 예방수의학회지 Vol.27 No.2
To summarize, mastitis infections attract white blood cells to move into the mammary gland. Their trafficking to the milk will cause a path of secretory cell destruction in their wake. This results in a leaky milk secretory system where components of the blood leak into the milk, reducing milk quality. Control of both contagious and noncontagious pathogens is warranted. There is a need to monitor the mastitis situation as closely as possible, and to root out the problem when it occurs by looking for the fundamental break-down in control. Mycoplasma mastitis seems to be increasing in prevalence. The best method to keep a hand on the pulse of the mycoplasma mastitis situation in a herd is to perform routine bulk tank milk cultures. The appearance of Mycoplasm sp. in the culture indicates that cows have mycoplasma mastitis. However, bulk tank milk cultures may yield false negative results. At times cows with mycoplasma mastitis may be shedding this pathogen at very low levels, not detectable in bulk tank milk. But with routine, perhaps weekly, bulk tank cultures, a dairy manager should feel confident that mycoplasma mastitis problems will be revealed. Once revealed, it is important that managers search and isolate infected cows, since mycoplasma mastitis is contagious. Yet the source of mycoplasma mastitis may not be exclusively the mammary gland. If future research definitively identifies different sources of this pathogen, such as colonization at other body sites, then new strategies need to be developed to control, and prevent, mycoplasma mastitis. The goal of mastitis control is illustrated in Table 1.
Suppression of bovine T lymphocytes responses by the superantigen staphylococcal enterotoxin C
Witold A. Ferens,Gregory A. Bohach,William C. Davis,Lawrence K. Fox,이상운(Sang Un Lee),박용호(Yong Ho Park) 한국예방수의학회 1998 예방수의학회지 Vol.22 No.3
Staphylococcus aureus에 의한 유방염은 주로 만성으로 경과되며 항생제 치료에 대한 저항성을 나타낸다. 기존의 보고에 의하면, 이 질병은 동일항원 혹은 다른 종류의 항원에 대한 면역반응의 억제와 관련된다고 알려져 있으나, 이러한 효과와 관련된 특이적인 인자는 아직 밝혀지지 않고 있다. 본 실험은 superantigen으로 알려진 포도상구균 장독소가 유방염의 숙주방어기전에 간섭하리라는 가능성을 제시하였다. 본 실험에서 포도상구균 장독소 C형 (SEC)은 in vitro상에서 세포증식의 억제와 CD8⁺T 림프구 표면의 ACT3 marker의 과다 발현에 의해 특징지어지는 소 T 림프구의 일탈된 활성을 유도하였다. SEC에 의한 소 T 림프구의 증식반응은 일시적이었으며, 배양 4일 후에는 ACT1, ACT16 및 IL-2Rα 등 활성세포 표면인자의 증가와 연관되어 왕성한 증식을 나타내었다. 비록 CD4⁺T 림프구와 CD8⁺T림프구는 배양 후 4일과 7일 사이에 증식을 나타내었지만, 상대적으로 CD8⁺T 림프구 아집단의 증식이 더 왕성하였으며 이로 인해 CD4:CD8 비율이 반전되는 결과를 가져왔다.
Immunosuppression by T regulatory cells in cows infected with Staphylococcal superantigen
박용호,Byoung Sun Chang,Gregory A.Bohach,Sang-Un Lee,William C.Davis,Lawrence K.Fox,Witold A.Ferens,Keun Seok Seo,Hye Cheong Koo,Nam Hoon Kwon 대한수의학회 2005 Journal of Veterinary Science Vol.6 No.3
Our recent study has provided that the in vitro SECinduced proliferation of bovine T cells is preceded by a period of a non-proliferative immunoregulation of T cells that may be associated with cytokine production regulated by type 1 or type 2 T cells. Inversion of CD4+:CD8+ T cell ratio and induction of CD8+ T cells with immunoregulatory activity could increase the probability of intracellular survival of Staphylococcus aureus (S. aureus). The increase of activated CD8+ (ACT2+ BoCD8+) T cells in cows with mastitis caused by S. aureus may be associated with immune-regulatory function in the bovine mammary gland. The difference and similarity between bovine activated CD8+ T cells (CD8+CD26+) and well-established human CD4+CD25+ T regulatory (Tr) cells may help to reveal their unique immune regulatory system in the host infected with S. aureus.
Unique features of bovine lymphocytes exposed to a staphylococcal enterotoxin
박용호,Sang Un Lee,Witold A. Ferens,Sparrow Samuels,William C. Davis,Lawrence K. Fox,Jong Sam Ahn,Keun Seok Seo,Byoung Sun Chang,황선영,Gregory A. Bohach 대한수의학회 2006 Journal of Veterinary Science Vol.7 No.3
We previously demonstrated that stimulation of bovine peripheral blood mononuclear cells (PBMCs) with staphylococcal enterotoxin C (SEC), led to an inversion of the CD4+:CD8+ T cell ratio and generation of an atypical CD8+ T cell subpopulation expressing CD26. In the present study, we examined T cell apoptosis and proliferation profiles of PBMC subpopulations in cultures stimulated with SEC. Unlike when stimulated with concanavalin A, nucleic acid synthesis in bovine PBMC cultures stimulated with SEC was low during the first four days but increased greatly on day 5. In contrast, nucleic acid synthesis in human PBMC cultures stimulated with SEC increased continuously. To investigate the mechanism of delayed bovine T cell proliferation, various cell phenotypes were monitored. The inversion of the bovine CD4+:CD8+ T cell ratio in PBMC cultures stimulated by SEC was associated with higher proliferation and lower apoptosis of CD8+ T cells compared to CD4+ T cells. The mRNA levels for interleukin (IL)-4 and IL-13 were sustained over 4 days but IL-12 mRNA levels dropped to background on day 2. These data suggest that SEC induces a prolonged Th-2- biased microenvironment, and together with the inversion of the bovine CD4+:CD8+ T cell ratios in bovine PBMC cultures with SEC, may in part explain the inability of the mammary immune system to establish an effective response to Staphylococcus aureus infections.