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1.
The objective of this study was to determine the mechanism by which insulin-like growth factor-I (IGF1) stimulates proliferation of mammary epithelial cells, using the bovine mammary epithelial cell line MAC-T as a model. IGF1 significantly up- or down-regulated the expression of 155 genes in MAC-T cells. Among the most significantly suppressed was the gene for connective tissue growth factor (CTGF), a secretory protein that has both proliferative and apoptotic effects and is also a low-affinity binding protein of IGF1. IGF1 inhibited CTGF expression through the PI3K-Akt signaling pathway. Administration of growth hormone (GH), a strong stimulator of IGF1 production in vivo, decreased mammary CTGF mRNA in cattle; however, GH did not affect CTGF expression in MAC-T cells, suggesting that IGF1 may also inhibit CTGF expression in the mammary gland. Added alone CTGF stimulated proliferation of MAC-T cells, but in combination with IGF1 it attenuated IGF1's stimulation of proliferation of MAC-T cells. Excess IGF1 reversed this attenuating effect of CTGF. Despite being an IGF binding protein, CTGF did not affect IGF1-induced phosphorylation of IGF1 receptor (IGF1R) or IGF1R expression in MAC-T cells, indicating that the attenuating effect of CTGF on IGF1 stimulated proliferation of MAC-T cells was not mediated by decreasing IGF1's ability to bind to IGF1R or by decreasing IGF1R expression. Overall, these results suggest a novel biochemical and functional relationship between CTGF and IGF1 in the bovine mammary gland, where IGF1 may inhibit CTGF expression to reduce the attenuating effect of CTGF on IGF1 stimulated proliferation of epithelial cells.  相似文献   

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4.
In order to compare the intracellular concentration of antimicrobial agents in phagocytic and nonphagocytic cells, the knowledge of their cell volume is essential. For the first time, the determination of the avian, porcine, and bovine polymorphonuclear neutrophils (PMN), monocyte-derived macrophages, macrophages, and bovine mammary epithelial cell volume was performed using [3H]-water and [14C]-carboxyinulin. The comparison of all the cells showed that the PMN have a size range between 3.58 and 4.04 microL per mg of protein, and are smaller than the monocyte-derived macrophages and mammary epithelial cells (4.32-5.01 microL per mg of protein). The macrophages show the largest size (5.84-6.57 microL per mg of protein). The cellular uptake of tilmicosin in these cells was then determined. The examination of the intracellular/extracellular concentration ratios (Ci/Ce) after 4 h of incubation with 10 mg/mL of [14C]-labelled tilmicosin revealed that tilmicosin was well accumulated and showed a ratio of 137, 169 and 193 in avian PMN, porcine PMN, and bovine alveolar macrophages, respectively. The cellular uptake data also demonstrated that tilmicosin accumulated in nonphagocytic bovine mammary epithelial cells. The importance of the use of the appropriate species and cell type specific cell volume values for calculations was exemplified by calculating the Ci/Ce of tilmicosin using cell volume data found in the literature for human and mouse cells. The subsequent comparison of these data with the Ci/Ce calculated with the actual cell volume appropriate for the species tested revealed an under evaluation of 3-13% in monocyte-macrophages, an over evaluation of 7-18%, 16-31% and 69% in PMN, macrophages, and epithelial cells, respectively. This study highlights the importance of the proper cell volume in order to determine the Ci/Ce. Moreover, the cell volumes determined here for avian, porcine and bovine cells should facilitate further in vitro and in vivo cellular studies by veterinary researchers.  相似文献   

5.
The bovine mammary alveolar cell-T (MAC-T) cell line is able to uniformly differentiate and secrete casein proteins in response to dexamethasone, insulin, and prolactin and is extensively used to study bovine mammary epithelial cell (MEC) function. Somatotropin, or growth hormone (GH), has been shown to increase milk protein synthesis both in vivo and in mammary cell models and to induce cytoskeletal rearrangement in a 3T3 fibroblast cell line and a Chinese hamster ovary cell line. To identify the nature of the effects of GH in MECs cultured with lactogenic hormones, changes in global protein expression were assessed in the MAC-T cell line with the use of two-dimensional gel electrophoresis and matrix-assisted laser desorption ionization tandem time of flight mass spectrometry. Forty proteins were differentially expressed in response to GH (P < 0.05) and were related to metabolism, the cytoskeleton, protein folding, RNA and DNA processing, and oxidant stress. These widespread changes in protein expression are indicative of a global role of GH in overall cellular differentiation that may underlie the direct modulation of milk component synthesis in MEC models that have been described to date.  相似文献   

6.
本试验旨在研究中国蜂胶乙醇提取物（ethanol extract of Chinese propolis，EECP）对细菌脂多糖（lipopolysaccharide，LPS）刺激下体外培养奶牛乳腺上皮细胞炎症相关基因mRNA转录水平和紧密连接渗透性的影响。EECP中总酚酸和总黄酮含量测定采用福林酚法和硝酸铝法，并建立LPS诱导奶牛乳腺上皮细胞（bovine mammary epithelial cells，MAC-T）炎症模型，采用CCK-8法测定EECP对MAC-T相对增殖率的影响，利用实时荧光定量PCR（RT-qPCR）评估EECP对LPS诱导的MAC-T细胞炎症相关因子（IL-6、IL-8、TNF-α和IL-1β）相对mRNA转录水平；以及对紧密连接蛋白（occludin、ZO-1）相对mRNA转录水平进行检测，并进一步利用免疫荧光技术对紧密连接膜蛋白进行定位，确定EECP对LPS诱导MAC-T细胞炎症紧密连接渗透性的影响。结果显示：EECP中总酚酸含量为106.35 mg没食子酸当量（GAE）·g-1、总黄酮含量为320.85 mg芦丁当量（RE）·g-1；CCK-8结果显示EECP的安全浓度为0~15 μg·mL-1，并可有效提高LPS刺激下MAC-T的活力；LPS刺激显著增加了细胞炎症相关因子IL-6、IL-8、TNF-α和IL-1β mRNA的转录量（P<0.001）；但2.5~15.0 μg·mL-1 EECP预处理显著降低了IL-6、IL-8、TNF-α和IL-1β mRNA的转录量；与此类似，LPS刺激显著抑制了紧密连接蛋白基因（occludin、ZO-1）mRNA的转录量（P<0.01），而EECP预处理后紧密连接蛋白基因（occludin和ZO-1）mRNA的转录量显著增加（P<0.05）；免疫荧光染色试验也证实EECP能通过上调紧密连接蛋白（occludin、ZO-1）的表达，缓解LPS诱导的乳腺上皮细胞屏障功能紊乱。该结果证实，EECP对细菌脂多糖诱导奶牛乳腺上皮细胞炎症具有良好的保护作用，这为利用中国蜂胶预防奶牛乳腺炎提供了试验基础。  相似文献   

7.
A microassay system was developed to quantify bovine neutrophil transepithelial migration in vitro. The bovine mammary epithelial cell line (MAC-T) formed a confluent monolayer that served as a biologically meaningful barrier for neutrophil migration. Neutrophils added into the upper compartment of an inverted monolayer were driven to migrate across the epithelium from a basal-to-apical direction by the addition of zymosan activated serum (ZAS) into the lower compartment. The numbers of migrated neutrophils were determined by assaying the neutrophil azurophilic granule marker, myeloperoxidase. Results showed that ZAS stimulated neutrophil migration across the epithelium in a time-and dose-dependent manner. In the presence of 5% ZAS and 2 x 10(6) neutrophils, approximately 2.4 x 10(5) neutrophils migrated across the epithelium in 120 min. The procedures we have developed in this study provide a simple precisely controlled system to investigate the normal dynamics of bovine neutrophil transepithelial migration and a means to detect and study impaired neutrophil migration.  相似文献   

8.
The objectives of the experiment were (1) to determine whether MAC-T cells would accurately mimic the previously observed proliferative responses of primary mammary epithelial cells (MEC) to mammary tissue extracts from high and low-fed heifers and (2) to determine whether mammary tissue extracts from ovariectomized (OVX) heifers would have lower mitogenic activity than intact controls. Addition of mammary tissue extracts to cell culture media of MAC-T cells plated on plastic or collagen-coated plastic to a range of concentrations between 1 and 8% resulted in dose-dependent increases in cell proliferation. Furthermore, mammary tissue extracts from low-fed prepubertal heifers aged 9 months, stimulated significantly more proliferation of MAC-T cells, as measured by 3H-thymidine incorporation into DNA than mammary tissue extracts from high-fed heifers (40.6 cpm x 10(3) per well versus 21.9+/-1.8 cpm x 10(3) per well). These observations suggested that MAC-T cells would be a suitable alternative to primary MECs for measuring the mitogenic activity of mammary tissue extracts. Conversely, no difference was observed in the mitogenic activity of mammary tissue extracts from OVX or control heifers. Possibly, MAC-T cells provide a good model for nutrition- but not ovarian-induced changes in mammary growth. Alternatively, that reduction of in vivo mammary development following OVX did not result in reduced mitogenic activity of the mammary tissue extracts emphasizes that heifer mammary development is the result of complex interactions between local growth factors and systemic hormones.  相似文献   

9.
Neutrophil (PMN) contribution to the acute inflammatory processes may lead to an excessive generation of reactive oxygen metabolites species (ROS) and secretion of granule enzymes. We compared the effects of either phorbol myristate acetate (PMA) or N-formyl-methionyl-leucyl-phenylalanine (fMLP) in combination with a pre-treatment by cytochalasin B (CB) on the production of ROS and the release of total and active myeloperoxidase (MPO) by isolated equine PMNs. The ROS production was assessed by lucigenin dependent chemiluminescence (CL) and ethylene release by α-keto-γ-methylthiobutyric acid (KMB) oxidation. In the supernatant of activated PMNs, total equine MPO was measured by ELISA and active MPO by the SIEFED (Specific Immunologic Extraction Followed by Enzymatic Detection) technique that allows for the study of the interaction of a compound directly with the enzyme. The stimulation of PMNs with CB-fMLP only modestly increased the release of MPO, but more than 70% of released MPO was active. PMA stimulation markedly increased the production of ROS and release of MPO, but more than 95% of released MPO was inactive. When PMNs were pre-incubated with superoxide dismutase (SOD) prior to PMA activation, the lucigenin enhanced CL, which is linked to the superoxide anion (O2−) production, was much more decreased than KMB oxidation, linked to the hydroxyl-like radical production. The addition of SOD prior to the activation of PMNs by PMA also limited the loss of the activity of released MPO. These results confirm the key role of O2− generation in the ROS cascade in PMN and reveal its critical role on MPO inactivation.  相似文献   

10.
The dynamics of apoptosis of polymorphonuclear leukocytes (PMN) during induced influx of PMN into the cavity system of the juvenile bovine mammary gland in order to investigate the role of apoptosis of PMN in the resolution of mastitis was studied. The instillation of a synthetic analogue of muramyl dipeptide into teat sinus of the sixteen mammary glands was followed by a massive influx of PMN culminating after 24 h and resolving after 96 h. Every 24 h following the influx, apoptotic PMN were microscopically detected, based on morphological characteristics. Twenty four hours after the stimulation, apoptotic PMN were already observed, and peak counts of apoptotic PMN were reached 48 h after the stimulation. The lowest differential count of apoptotic PMN, corresponding to the pre-stimulation value, was found 96 h after the stimulation. The presence of macrophages (MAC) containing phagocytized apoptotic PMN was observed by histochemical staining for myeloperoxidase (MPO) and electron microscopy. The percentage of MPO-positive macrophages increased during the resolution phase to reach peak values 48 h after the stimulation. Apoptosis of PMN and phagocytosis by macrophages may represent a removal mechanism that is important in the resolution of the induced influx of PMN in the cavity system of juvenile bovine mammary gland.  相似文献   

11.
Production and regulation of leptin in bovine mammary epithelial cells   总被引：1，自引：0，他引：1  
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12.
Streptococcus uberis is a significant cause of bovine mastitis throughout the world. Previous work from our laboratory demonstrated that S. uberis adhesion molecule (SUAM) is an important factor in adherence to and internalization of S. uberis into bovine mammary epithelial cells. Antibodies directed against SUAM significantly reduced bacterial adherence to and internalization into bovine mammary epithelial cells implying that SUAM is surface exposed. Objectives of this research were to: (1) predict surface exposed peptides, and (2) select peptide sequences for production of synthetic peptides with the final aim of evaluating their role in adherence and internalization and immunogenic potential. The Kyte/Doolittle hydropathicity prediction method; Chou/Fasman β-turn prediction method; and output from Coils, Paircoil and MultiCoil scores for prediction of secondary and tertiary structures were used. Prediction algorithms resulted in identification of five overlapping regions of the SUAM sequence with the most hydrophilic valleys and the highest peaks for β-turns. The five 15-mer SUAM epitopes selected by bioinformatic analysis were produced to evaluate the immunogenic value and pathogenic role of these putative domains. Peptides were bound to fluorescent latex beads, incubated with MAC-T bovine mammary epithelial cells, and internalization into MAC-T cells was evaluated using confocal laser and transmission electron microscopy. All peptides evaluated induced some degree of internalization of fluorescent beads into MAC-T cells; however, 2 peptides induced significantly more internalization of fluorescent beads than the other peptides evaluated. These peptides, designated III and IV, were located in the central region of SUAM, between two coiled-coil regions. Convalescent sera were tested against these biotinylated peptides for SUAM specific immune response using an indirect ELISA format. Among the 5 peptides evaluated, peptides I, II and V elicited significant serological response suggesting that the N-terminal region (peptide I), central region (peptide II) and C-terminal region (peptide V) are immunodominant epitopes of SUAM. Results will be useful to design immunotherapeutic tools based on immunodominant epitopes.  相似文献   

13.
本研究拟通过分析丁酸钠对脂多糖(LPS)诱导的奶牛乳腺上皮细胞系(MAC-T细胞)炎性损伤的修复作用,进一步从体外角度阐述丁酸钠对奶牛乳腺健康的调控机制。在MAC-T细胞中添加不同浓度(0、1、10、100、1 000、10 000 ng/mL)的LPS,检测细胞活力,以确定LPS的适宜浓度,建立细胞氧化损伤模型;并进一步在MAC-T细胞中添加不同浓度(0、2、4、8、16、32μmol/L)的丁酸钠,检测细胞凋亡率,以确定丁酸钠的适宜浓度。最终选用1 000 ng/mL LPS和16μmol/L丁酸钠用于本试验。试验分为3组,分别为对照组、LPS处理组和LPS+丁酸钠处理组,分别对其细胞形态、氧化应激指标及凋亡蛋白mRNA表达水平进行检测。结果表明：1)对照组MAC-T细胞呈扁平的无规则形态,贴壁状态良好;而LPS处理组MAC-T细胞核固缩、破裂,并出现大面积死亡脱落现象;LPS+丁酸钠处理组MAC-T细胞边缘清楚,胞内颗粒较少,死亡脱落现象明显减少。2)与对照组相比,LPS处理组MAC-T细胞中超氧化物歧化酶(SOD)活性和总抗氧化力(T-AOC)显著降低(P<0.05),丙...  相似文献   

14.
Effects of polymorphonuclear neutrophil leukocytes (PMN) on mammary tissue of lactating cows were studied in vitro. The PMN were isolated from mammary glands of nulliparous heifers given an injection of 5 micrograms of Escherichia coli endotoxin. Mammary tissue was obtained from noninfected quarters of 5 lactating Holstein cows and was cultured in supplemented medium 199. Mammary explants were treated by addition of intact or lysed PMN (10(5), 10(6), 10(7)/ml) or PMN (10(5), 10(7)/ml) which were allowed to phagocytose opsonized zymosan. Controls included cultures of mammary tissue alone, PMN alone, and mammary tissue plus zymosan. Cultures were incubated at 37 C for 3, 8, or 24 hours. Tissue from 1 randomly selected culture/treatment was weighed and processed for microscopy. Tissue from remaining cultures was incubated with [3H]amino acids or [14C]acetate to determine rates of protein and fatty acid synthesis. Media from all cultures were assayed for activity of the lysosomal enzyme, N-acetyl-beta-D-glucosaminidase. An increase (P less than 0.02) in the activity of this enzyme was detected in the medium of explant cultures treated with 10(7) phagocytosing PMN/ml at 3 and 8 hours and with 10(7) intact or lysed PMN/ml at 8 hours. Treatment did not inhibit (P greater than 0.05) rates of protein or fatty acid synthesis. Microscopic examination indicated that epithelial cell damage resulted from treatment with 10(6) and 10(7) intact, lysed, or phagocytosing PMN/ml. Greatest morphologic damage resulted from treatment with phagocytosing PMN.  相似文献   

15.
Relaxin is a peptide hormone produced by a wide variety of mammals. In the horse, the placenta is the major source of relaxin. Since pure equine relaxin is difficult to obtain to study its role in the pregnant mare, the objectives of this study were to produce recombinant equine prorelaxin and characterize its immunological and biological activity. First, an equine relaxin gene cassette was transfected into immortalized bovine mammary epithelial (MAC-T) cells. Second, immunological activity of media conditioned by transfected MAC-T cells was tested by Western blotting and quantified using a homologous equine radioimmunoassay. Finally, bioactivity of the conditioned media was tested using the human monocyte cell line, THP-1, which exhibits a rapid and dose-dependent increase in the accumulation of cAMP upon binding relaxin. The results showed that conditioned media, concentrated 5x, yielded 4.11 +/- 0.81 ng/ml recombinant equine prorelaxin. In addition, a 19 kDa immunoreactive band, corresponding to the expected size of equine prorelaxin, was visualized by SDS-PAGE. THP-1 cells incubated with conditioned media (5x) from transfected cells, in the presence of forskolin (1 microM) and isobutylmethylxanthine (50 microM), showed an increase in cAMP production over media from mock-transfected cells alone. In conclusion, recombinant equine prorelaxin secreted by MAC-T cells was both immunologically and biologically active. This study demonstrates the first attempt to produce recombinant equine prorelaxin, important for further study of the role of relaxin in the mare.  相似文献   

16.
奶牛乳腺炎是指在不同理化因素刺激下奶牛乳腺的炎性反应,其严重影响了奶牛养殖业的健康发展。许多细胞因子是炎症调节剂,但与奶牛乳腺炎相关的关键细胞因子还未被鉴定。异体移植炎症因子1（allograft inflammatory factor-1,AIF-1）在免疫调节中扮演重要角色,并在多种炎性疾病中过量表达。因此,本研究探讨了牛AIF-1在乳腺炎中的可能作用。首先,利用ELISA试剂盒检测了乳腺炎牛奶中牛AIF-1的含量,并用RT-PCR方法克隆牛AIF-1基因,然后,用亲和层析纯化牛AIF-1蛋白。用此重组蛋白刺激牛乳腺上皮细胞,ELISA试剂盒检测肿瘤坏死因子α、白细胞介素6和单核细胞趋化蛋白1的分泌,Western blot测定IκBα的磷酸化。结果显示,患乳腺炎奶牛乳中AIF-1的平均含量显著高于健康奶牛,而抗生素治愈后的奶牛乳中AIF-1的含量回落到正常水平。这些结果提示,牛AIF-1是一个分泌型蛋白,可能与乳腺炎相关。为了进一步探索这种关系,本研究克隆了牛AIF-1基因并纯化了牛AIF-1蛋白。此蛋白上调了牛乳腺上皮细胞肿瘤坏死因子α、白细胞介素6和单核细胞趋化蛋白1的分泌,并刺激了IκBα的磷酸化。IκBα磷酸化抑制剂BAY 11-7085阻断了牛AIF-1刺激的炎性细胞因子上调。综上表明,牛AIF-1通过核因子κB信号促进了牛乳腺上皮细胞炎症因子的释放。  相似文献   

17.
Mastitis, inflammation of the mammary gland, is a common and economically important disease in dairy animals. Mammary pathogenic organisms, such as Escherichia coli, invade the teat canal,milk ducts, and mammary alveolar space, replicate in mammary secretions, and elicit a local inflammatory response characterized by massive recruitment of blood polymorphonuclear neutrophil leukocytes (PMN) into the alveoli and milk ducts. CD44 is a trans-membrane glycoprotein previously shown to play a role in mediation and control of blood PMN recruitment in response to inflammatory signals. Here we show, for the first time, increased expression of CD44 on recruited milk PMN in bovine mastitis and the expression of a CD44 variant, CD44v10, on these PMN. Furthermore, we demonstrate that CD44 mediates specific adhesion of bovine blood PMN to hyaluronic acid and mammary epithelial cells. Our results suggest that in mastitis CD44 plays a role in recruiting blood PMN into the mammary glands, the exact nature of this role needs to be elucidated.  相似文献   

18.
The effect of diapedesis on the phagocytic and oxidative burst activity of polymorphonuclear neutrophil (PMN) was examined, using an in vitro cell culture model consisting of a monolayer of primary mammary epithelial cells. Isolated blood PMN from 10 cows were added to the basal side of the epithelial cell monolayer. Diapedesis was induced by the addition of complement factor C5a to the apical side of the monolayer. PMN phagocytosis of Staphylococcus aureus and oxidative burst were measured before diapedesis on PMN that were non-activated and activated by incubation with C5a and on PMN after diapedesis, using flow cytometry. The percentages of PMN fluorescing due to phagocytosis of S. aureus and oxidative burst were reduced by 21.2 and 14.4%, respectively, after diapedesis. Pre-incubation in the presence of C5a had no effect on percentage PMN fluorescing due to phagocytosis or oxidative burst. The capacity for individual migrated PMN to phagocytose S. aureus and to produce an oxidative burst, as measured by the intensity of fluorescence, decreased by 34.2 and 30.3%. Activation of PMN with C5a increased intensity due to the oxidative burst, but had no effect on intensity due to phagocytosis. These data show that PMN diapedesis across mammary epithelium results in decreased phagocytosis and oxidative burst of the PMN.  相似文献   

19.
本试验旨在研究不同浓度的组氨酸对体外培养奶牛乳腺上皮细胞β-酪蛋白及酪氨酸激酶2(JAK2)-信号转导与转录激活子5(STAT5)/哺乳动物雷帕霉素靶蛋白(m TOR)信号通路相关磷酸化蛋白表达的影响。将原代奶牛乳腺上皮细胞进行体外培养,分为对照组和7个试验组,采用无必需氨基酸的培养基,对照组不添加组氨酸,试验组是在对照组基础上分别添加0.15、0.60、1.20、2.40、4.80、9.60、19.20 mmol/L的组氨酸。采用噻唑蓝比色法检测原代奶牛乳腺上皮细胞12 h增殖情况;运用蛋白质免疫印迹检测β-酪蛋白和8个信号通路相关磷酸化蛋白表达。结果表明:1)当组氨酸浓度为0.15~9.60 mmol/L时,与对照组相比,奶牛乳腺上皮细胞数量均增加。2)β-酪蛋白表达量随组氨酸浓度的增加出现先升高后降低的趋势,但试验组均极显著高于对照组(P0.01)。3)与对照组相比,组氨酸的添加可极显著促进各信号通路相关磷酸化蛋白的表达(P0.01);试验组中,随着组氨酸浓度的升高,磷酸化哺乳动物雷帕霉素靶蛋白[P-m TOR(Ser2481)]和磷酸化真核细胞翻译延伸因子2[P-e EF2(Thr56)]蛋白的表达量下降,而磷酸化核糖体S6蛋白激酶1[P-S6K1(Thr389)]的蛋白表达增加;当组氨酸浓度为2.40 mmol/L时,磷酸化酪氨酸激酶2[P-JAK2(Tyr1007/1008)]、磷酸化真核细胞始动因子4E结合蛋白1[P-4EBP1(Thr37)]和磷酸化真核细胞起始因子2α[P-e IF2α(Ser51)]蛋白的表达量最高,磷酸化信号转导与转录激活子5[P-STAT5(Tyr694)]、磷酸化m TOR调控蛋白[P-raptor(Ser863)]和m TOR复合物1中的绑定蛋白(GβL)蛋白在组氨酸浓度为9.60 mmol/L时表达量最高。综合可知,组氨酸的添加可通过促进JAK2-STAT5信号通路中P-JAK2(Tyr1007/1008)和PSTAT5(Tyr694)蛋白的表达来进而调控β-酪蛋白表达。最适浓度(0.15~9.60 mmol/L)范围内的组氨酸还可通过m TORC1的P-raptor(Ser863)蛋白作用于下游靶点P-4EBP1(Thr37)来促进β-酪蛋白表达,最终调控乳蛋白合成。  相似文献   

20.
Staphylococcus aureus is recognized worldwide as a major pathogen causing clinical or subclinical intramammary infections in lactating cows, sheep and goats. S. aureus produces a wide arsenal of cell surface and extracellular proteins involved in virulence. Among these are two conserved proteins with glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity named glyceraldehyde-3-phosphate dehydrogenase-B (GapB) and -C (GapC). In this study, we used the S. aureus wild type strain RN6390 and its isogenic gapC mutant H330 in in vitro and in vivo studies and determined that the S. aureus GapC protein plays a role on adherence to and internalization into bovine mammary epithelial (MAC-T) cells. In addition, we found that S. aureus H330 did not caused mastitis after an experimental infection of ovine mammary glands. Together, these results show that GapC is important in the pathogenesis of S. aureus mastitis.  相似文献   

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