被动免疫轮状病毒NSP4&VP7双抗原重组腺病毒对感染乳鼠的排毒保护作用

为建立小鼠轮状病毒(Rotavirus,RV)感染动物模型,研究可同时表达轮状病毒NSP4 (Nonstructural protein 4)和VP7(Viral protein 7)的重组腺病毒疫苗免疫孕鼠后对新生乳鼠感染RV的被动保护作用.新生乳鼠口服异源株轮状病毒Wa、ZTR-68或SA11株后(分2次给予,每次含5×104 CCID50的RV),观察乳鼠是否有腹泻症状、肠道病理变化,检测乳鼠粪便排毒百分率;另以重组腺病毒rAd-NSP4-VP7免疫孕鼠后,检测母鼠血清抗体产生情况,并对比乳鼠粪便中RV抗原检出率初步评价疫苗的被动免疫保护作用.发现口服异源株RV的乳鼠未出现类似人类婴幼儿感染后的明显腹泻症状,但在粪便中可检测到RV抗原的存在(Wa、ZTR-68攻毒组均超过80％).经rAd-NSP4-VP7被动免疫的乳鼠接受Wa和ZTR-68攻毒后其粪便中的RV检出率比未受到被动免疫保护的对照组降低(P＜0.05).rAd-NSP4-VP7重组腺病毒免疫母鼠可显示出对孕鼠感染RV的被动免疫保护作用.     

人轮状病毒NSP4蛋白的表达及其致小鼠腹泻作用的初步研究

研究人轮状病毒非结构蛋白NSP4在轮状病毒致病性中的作用。分离得到我国人轮状病毒97SZ8株,以谷胱甘肽S-转移酶融合蛋白的形式在大肠杆菌BL-21中表达NSN蛋白C端86-175氨基酸并用G1utathione SepharoseTM 4B亲和纯化。将纯化蛋白分别以0．4nmol和1．5nmol的剂量腹腔注射新生Balb／C乳鼠,记录腹泻发生和体重变化情况。当注射0．4nmol GST-NSP4重组蛋白时,有1只小鼠发生-过性腹泻(1／6),给予1．5nmol重组蛋白时,实验组所有乳鼠都先后出现了腹泻,存在一定的剂量依赖性。本研究初步在新生小鼠建立了一种人轮状病毒腹泻动物模型,该模型有望在人轮状病毒的致腹泻机理、治疗和预防研究中发挥重要作用。     

人轮状病毒NSP4蛋白的表达及其致小鼠腹泻作用的初步研究

研究人轮状病毒非结构蛋白NSP4在轮状病毒致病性中的作用.分离得到我国人轮状病毒97SZ8株,以谷胱甘肽S-转移酶融合蛋白的形式在大肠杆菌BL-21中表达NSP4蛋白C端86-175氨基酸并用GlutathioneSepharoseTM 4B亲和纯化.将纯化蛋白分别以0.4nmol和1.5nmol的剂量腹腔注射新生Balb/C乳鼠,记录腹泻发生和体重变化情况.当注射0.4nmol GST-NSP4T重组蛋白时,有1只小鼠发生一过性腹泻(1/6),给予1.5nmol重组蛋白时,实验组所有乳鼠都先后出现了腹泻,存在一定的剂量依赖性.本研究初步在新生小鼠建立了一种人轮状病毒腹泻动物模型,该模型有望在人轮状病毒的致腹泻机理、治疗和预防研究中发挥重要作用.     

汉滩病毒核蛋白与热休克蛋白GRP94、HSP27的相互作用

为研究汉滩病毒(Hantaan virus, HTNV)感染诱导乳鼠脑组织热休克蛋白GRP94、HSP27与病毒蛋白的相互关系,选出生2～3d的昆明乳鼠实验性感染汉滩病毒,取8d后发病乳鼠脑组织部分制石蜡切片,用免疫组化结合共聚焦显微镜检测组织中病毒抗原及GRP94、HSP27的表达,部分制匀浆液,用ELISA、免疫共沉淀方法分析病毒抗原和GRP94、HSP27的关系.结果示汉滩病毒感染诱导乳鼠脑组织神经细胞高表达GRP94且与细胞内病毒抗原有共定位关系,但未见HSP27诱导高表达;免疫共沉淀显示汉滩病毒核心抗原(HINV-NP)与GRP94、HSP27呈非共价复合物形式存在.该结果为进一步探讨HSPs在病毒感染复制中的作用以及抗病毒感染方面提供了有意义的实验资料.     

汉滩病毒核蛋白与热休克蛋白GRP94、HSP27的相互作用

为研究汉滩病毒(Hantaan virus,HTNV)感染诱导乳鼠脑组织热休克蛋白GRP94、HSP27与病毒蛋白的相互关系,选出生2—3d的昆明乳鼠实验性感染汉滩病毒,取8d后发病乳鼠脑组织部分制石蜡切片,用免疫组化结合共聚焦显微镜检测组织中病毒抗原及GRP94、HSP27的表达,部分制匀浆液,用ELISA、免疫共沉淀方法分析病毒抗原和GRP94、HSP27的关系。结果示汉滩病毒感染诱导乳鼠脑组织神经细胞高表达GRP94且与细胞内病毒抗原有共定位关系,但未见HSP27诱导高表达;免疫共沉淀显示汉滩病毒核心抗原(HINV—NP)与GRP94、HSP27呈非共价复合物形式存在。该结果为进一步探讨HSPs在病毒感染复制中的作用以及抗病毒感染方面提供了有意义的实验资料。     

鸡产蛋下降综合征病毒NE4毒株对KM小鼠感染特性观察

目的初步探究鸡产蛋下降综合征病毒NE4（EDSV NE4）毒株对昆明小鼠的感染特性。方法用106TCID50攻毒量的EDSV NE4株对4～6周龄的KM小鼠进行攻毒试验,同时以正常尿囊液接种作为阴性对照。用荧光定量PCR对小鼠组织及粪便中的EDSV进行检测,同时用HE染色及免疫组化法对小鼠组织切片进行病理组织学观察和抗原定位。结果 EDSV攻毒对小鼠的采食情况产生一定影响,但并未引起明显的临床症状;攻毒组小鼠可产生针对EDSV特异性的抗体,HI抗体滴度可高达212,阴性对照组小鼠体内抗体检测为阴性;攻毒后小鼠大部分组织器官如肝脏、子宫、肾脏、肺脏等与攻毒7 d后粪便中均可检测到EDSV,阴性对照小鼠所有受检组织中均未检测到病毒;EDSV攻毒未能引起小鼠组织的病理学变化,攻毒后不同时间内,可在子宫、肺脏、肝脏、肾脏中可检测到阳性信号,最为典型的定殖位置是子宫腺体上皮细胞及肌层细胞的胞质中。结论 EDSV NE4株可以感染KM小鼠。     

EV71小鼠适应株制备及体内外感染特点

目的用1日龄ICR小鼠传代制备EV71小鼠适应株,研究EV71亲代株与小鼠适应株的体内外感染特点,建立EV71感染ICR小鼠动物模型,为病毒疫苗和抗病毒药物的研究提供实用的动物评价工具。方法用1日龄ICR小鼠进行EV71病毒(Fuyang-0805)的传代,得到小鼠传代株。以一定浓度亲代株和传代株病毒分别接种RD、Vero、SY5Y、Caco-2四种细胞,定量方法检测各时间点不同毒株在四种细胞上的复制数量,CCK8方法测定各时间点细胞的存活率;同时,两毒株分别腹腔注射感染1日龄小鼠,定期安乐死动物,采集肺、小肠、骨骼肌、大脑四种器官组织,进行动物体内病毒半定量和定量分析,同时进行各器官组织病理学观察、免疫组织化学鉴定。结果与亲代毒株相比较,小鼠传代株(EV71-MMP4)表现出更强的肌肉来源细胞嗜性与毒性;同时,两毒株腹腔注射感染1日龄小鼠后,EV71-MMP4感染的小鼠体重增长较正常小鼠体重增长缓慢;半定量和定量RT-PCR显示,在小鼠肌肉中的病毒载量于感染后1d和5d达到高峰。EV71-MMP4感染组感染率较高、病毒组织分布较广、感染持续性较好、病毒载量较高,高剂量病毒感染后小鼠小肠、心肌和骨骼肌可观察到细胞空泡变性、淋巴细胞浸润等病理变化。免疫组织化学显示感染后小鼠骨骼肌有EV71病毒特异分布。结论阜阳EV71小鼠适应株表现出较亲代毒株更好的小鼠易感性、细胞毒性,所建立的动物模型可用于EV71病毒致病机制、感染特点的研究和病毒疫苗及药物的评价。     

小儿副轮状病毒的检出

用聚丙烯酰胺凝胶电泳法,从婴幼儿急性腹泻粪便中检出轮状病毒RNA电泳阳性293份,发现一株副轮状病毒(青-27株),此株病毒经电泳观察,呈典型的轮状病毒形态,但易破碎。ELISA检测表明不具有一般轮状病毒的特异性群抗原,病毒RNA基因组由11个片段组成,但电泳图型特殊,吴4:3:2:2排列模式,本文证实,此一小儿副轮状病毒与国外报道的,散发罕见的小儿副轮状病毒RNA电泳图型相同,提示此病毒的重要意义。     

免疫抑制剂地塞米松可明显延长乙型肝炎病毒抗原在水动力法转染HBV小鼠模型中的表达

建立基于高压水动力法的乙型肝炎病毒(HBV)转染小鼠模型,并进一步建立和优化乙肝动物模型研究方法。首先构建了含腺相关病毒倒转末端重复序列元件与包含1.3个拷贝HBV基因组(ayw亚型)的HBV表达质粒(pAAV-HBV1.3);并将pAAV-HBV1.3质粒经高压水动力法尾静脉注射C57BL/6小鼠,不同时间点采集血液和肝组织标本,ELISA检测血清HBsAg、HBeAg表达;Real-time PCR检测血清及肝组织病毒载量;HE染色、免疫组化染色检测肝组织病理学改变及病毒抗原在肝组织中的定位及表达;最后采用免疫抑制剂地塞米松注射液(DEX)腹腔注射小鼠,建立免疫功能抑制小鼠模型,在此基础上制备乙肝病毒转染小鼠模型,并进行血清HBsAg、HBeAg检测。结果是正常免疫状态下,小鼠转染pAAV-HBV1.3 10d时血清及肝组织HBV相关抗原阳性,30d后HBV相关抗原检测阴性,但30d和60d血清及肝组织病毒载量检测均为阳性,且与对照组差异显著(P0.01,P0.05);经地塞米松注射后处于免疫抑制状态下的高压水动力法建立的乙肝病毒转染小鼠,则在60d仍可检测到HBsAg、HBeAg的表达。以上结果表明通过高压水动力法建立了急性乙肝小鼠模型,通过抑制小鼠免疫状态,可延长病毒在小鼠体内存留时间。该模型建立为HBV疫苗评价、药物开发及乙肝相关致病机理研究奠定了基础。     

中药止泻液对乳鼠轮状病毒肠炎水通道蛋白表达的影响

目的:用中药止泻液对轮状病毒肠炎乳鼠进行干预后,检测乳鼠空肠,回肠与近端结肠粘膜水通道蛋白(aquaporin,AQP)1,3,4,8mRNA的表达情况,研究中药止泻液对乳鼠轮状病毒肠炎AQP1,3,4,8mRNA表达的影响.方法:在实验条件下,用恒河猴SAll株轮状病毒感染6日龄乳鼠24h后,予各乳鼠灌注止泻液,每日3次,于接毒后48 h始,每天处死2只乳鼠,连续6天.采用实时荧光定量PCR方法对乳鼠的空肠,回肠与近端结肠黏膜细胞的AQP1,3,4,8 mRNA进行定性和相对定量分析研究,探讨中药止泻液对轮状病毒腹泻模型乳鼠肠道AQP1,3,4,8mRNA表达的影响.结果:结肠AQP1 mRNA在中药干预组乳鼠中表达量显著高于空白组(t=-3.47,P<0.05). AQP3,4,8mRNA表达量无统计学差异.在空肠,回肠中,中药干预组与空白组AQP1,3,4,8 mRNA袁达量均无统计学差异.结论:中药干预组乳鼠结肠AQP1 mRNA表达上升,提示中药止泻液能明显提高乳鼠结肠组织AQP1 mRNA的表达,通过增加结肠对水分的吸收,来达到收敛止泻的作用.在本研究中,中药止泻液对轮状病毒肠炎乳鼠肠道AQP3,4,8 mRNA表达没有明显的影响.     

轮状病毒感染成年小鼠的研究

目的研究成年昆明种小鼠对实验感染人轮状病毒(rotavirus,RV)的敏感性。方法在实验条件下,用A组人Wa和恒河猴SA11株RV感染成年昆明种小鼠,观察小鼠的临床反应和排毒情况。结果成年昆明种小鼠感染Wa和SA11RV第二天后出现明显的临床腹泻症状,第四天达到高峰;至少在感染后连续6天的动物大便中可检测到较高滴度的RV抗原。结论成年昆明种小鼠对RV感染有很高的敏感性,可做为动物模型,在RV感染的药物治疗效果评价和疫苗保护性效果评价中具有重要价值。     

Analyses of clinical, pathological and virological features of human rotavirus strain, YO induced gastroenteritis in infant BALB/c mice

Experimental studies of human rotavirus infections in mice are limited and there is lack of information on the quantitative assessment of rotaviral replication and its relationship with histological changes. In the present study, consequences of human rotavirus strain, YO induced gastroenteritis in infant BALB/c mice were analyzed for the occurrence of clinical symptoms, histopathology and virological events. The infected animals developed diarrhea and dehydration and showed accumulation of vacuolated enterocytes with lodging of the rotavirus antigens and shortening of villi in the intestine over a period of 5 days. The ileum was identified as the most susceptible and supportive part of small intestine for perpetuation of rotavirus infection in mice. Rotaviral antigen/RNA in stool and RNA in intestine were detected throughout the clinical disease period. At 48-72?h post inoculation, diarrhea was at the peak (90-95%) in the infected animals with increased load of viral RNA and intense pathological lesions suggesting it as the critical time point in the course of infection. The rising titers of antirotavirus neutralizing antibodies ascertained the replication of human rotavirus strain, YO in mice. These data may contribute to the understanding of pathophysiological, immunological and virological characteristics of rotavirus infections in mice.     

Rotavirus infection is not associated with small intestinal fluid secretion in the adult mouse

In contrast to humans, adult but not infant small animals are resistant to rotavirus diarrhea. The pathophysiological mechanism behind this age-restricted diarrhea is currently unresolved, and this question was investigated by studying the secretory state of the small intestines of adult mice infected with rotavirus. Immunohistochemistry and histological examinations revealed that rotavirus (strain EDIM) infects all parts of the small intestines of adult mice, with significant numbers of infected cells in the ilea at 2 and 4 days postinfection. Furthermore, quantitative PCR revealed that 100-fold more viral RNA was produced in the ilea than in the jejuna or duodena of adult mice. In vitro perfusion experiments of the small intestine did not reveal any significant changes in net fluid secretion among mice infected for 3 days or 4 days or in those that were noninfected (37 +/- 9 microl . h(-1) . cm(-1), 22 +/- 13 microl . h(-1) . cm(-1), and 33 +/- 6 microl . h(-1) . cm(-1), respectively) or in transmucosal potential difference (4.0 +/- 0.3 mV versus 3.9 +/- 0.4 mV), a marker for active chloride secretion, between control and rotavirus-infected mice. In vivo experiments also did not show any differences in potential difference between uninfected and infected small intestines. Furthermore, no significant differences in weight between infected and uninfected small intestines were found, nor were any differences in fecal output observed between infected and control mice. Altogether, these data suggest that rotavirus infection is not sufficient to stimulate chloride and water secretion from the small intestines of adult mice.     

Gastroenteritis caused by human rotaviruses (serotype three) in a suckling mouse model

The pathogenic potential of human rotaviruses of serotypes 1 through 4 was evaluated in suckling mice. Oral inoculation of three different human rotaviruses of serotype 3 into 5-6 day old CD-1 mice caused disease characterized by diarrhea and dehydration. The mean 50% diarrhea inducing dose (DD50) was 5 X 10(5) pfu. Histopathological examination of small intestines revealed villus epithelial cell vacuolization localized to the distal one-third of the villus. Only Serotype 3 rotaviruses exhibited a rapid phase of viral growth in the intestine between 7 and 12 hours post-inoculation. Larger inocula of rotavirus serotypes 1, 2, and 4 did not cause disease or typical histopathologic changes. However, immunoperoxidase staining for rotavirus antigen was positive in all serotypes tested indicating that infection can occur without apparent disease and is not serotype specific. This convenient in-vivo model can be used to evaluate attenuation of human origin vaccine candidates of serotype 3.     

Group A Rotavirus Infection and Age-Dependent Diarrheal Disease in Rats: a New Animal Model To Study the Pathophysiology of Rotavirus Infection

Group A rotaviruses are major pathogens causing acute gastroenteritis in children and animals. To determine if group A rotavirus replicates and induces disease in rats, antibody-negative Lewis neonatal or adult rats were inoculated orally with tissue culture-adapted human (Wa, WI61, and HAL1166), simian (rhesus rotavirus [RRV] and SA11), bovine (WC3), lapine (ALA), or porcine (OSU) rotavirus strains, wild-type murine (EC(wt)) rotavirus strain, or phosphate-buffered saline (PBS). Rotavirus infection in rats was evaluated by (i) clinical findings, (ii) virus antigen shedding or infectious virus titers in the feces or intestinal contents measured by enzyme-linked immunosorbent assay or fluorescent-focus assay, (iii) histopathological changes in the small intestine, (iv) distribution of rotavirus antigen in small-intestine sections by immunofluorescence, and (v) growth rate. Rotavirus infection of 5-day-old but not > or =21-day-old rats resulted in diarrhea that lasted from 1 to 10 days postinoculation. The severity of disease and spread of infection to naIve littermates differed depending on the virus strain used for inoculation. The duration of virus antigen shedding following infection was considerably prolonged (up to 10 days) in neonatal rats compared to that in 21-day-old rats (1 or 2 days). Based on lack of virus antigen shedding and disease induction, the murine EC(wt) rotavirus was the only strain tested that did not infect rats. Histopathological changes in the small-intestine mucosa of 5-day-old RRV-inoculated rats but not of PBS-inoculated rats was limited to extensive enterocyte vacuolation in the ileum. In RRV-inoculated neonatal rats, rotavirus antigen was detected in the epithelial cells on the upper half of the intestinal villi of the jejunum and ileum. In addition, infection of neonatal rats with RRV but not with PBS resulted in reduced weight gain. Rats infected with group A rotaviruses provide a new animal model with unique features amenable to investigate rotavirus pathogenesis and the molecular mechanisms of intestinal development, including physiological factors that may regulate age-dependent rotavirus-induced diarrhea.     

Rotavirus viremia and extraintestinal viral infection in the neonatal rat model

Rotaviruses infect mature, differentiated enterocytes of the small intestine and, by an unknown mechanism, escape the gastrointestinal tract and cause viremia. The neonatal rat model of rotavirus infection was used to determine the kinetics of viremia, spread, and pathology of rotavirus in extraintestinal organs. Five-day-old rat pups were inoculated intragastrically with an animal (RRV) or human (HAL1166) rotavirus or phosphate-buffered saline. Blood was collected from a subset of rat pups, and following perfusion to remove residual blood, organs were removed and homogenized to analyze rotavirus-specific antigen by enzyme-linked immunosorbent assay and infectious rotavirus by fluorescent focus assay or fixed in formalin for histology and immunohistochemistry. Viremia was detected following rotavirus infection with RRV and HAL1166. The RRV 50% antigenemia dose was 1.8 x 10(3) PFU, and the 50% diarrhea dose was 7.7 x 10(5) PFU, indicating that infection and viremia occurred in the absence of diarrhea and that detecting rotavirus antigen in the blood was a more sensitive measure of infection than diarrhea. Rotavirus antigens and infectious virus were detected in multiple organs (stomach, intestines, liver, lungs, spleen, kidneys, pancreas, thymus, and bladder). Histopathological changes due to rotavirus infection included acute inflammation of the portal tract and bile duct, microsteatosis, necrosis, and inflammatory cell infiltrates in the parenchymas of the liver and lungs. Colocalization of structural and nonstructural proteins with histopathology in the liver and lungs indicated that the histological changes observed were due to rotavirus infection and replication. Replicating rotavirus was also detected in macrophages in the lungs and blood vessels, indicating a possible mechanism of rotavirus dissemination. Extraintestinal infectious rotavirus, but not diarrhea, was observed in the presence of passively or actively acquired rotavirus-specific antibody. These findings alter the previously accepted concept of rotavirus pathogenesis to include not only gastroenteritis but also viremia, and they indicate that rotavirus could cause a broad array of systemic diseases in a number of different organs.     

Gastroenteritis in suckling mice caused by human rotavirus can be prevented with egg yolk immunoglobulin (IgY) and treated with a protein-bound polysaccharide preparation (PSK)

Oral inoculation of human rotavirus MO strain (serotype 3) into 5-day-old BALB/c mice cause gastroenteritis characterized by diarrhea. Clinical symptoms, histopathological changes in the small intestine, and the detection of rotavirus antigen in enterocytes were all characteristic of rotavirus-induced gastroenteritis. Using this small animal model, passive protection of suckling mice against human rotavirus infection was achieved with the use of immunoglobulin (IgY) from the yolks of eggs of rotavirus-immunized hens. When IgY against a rotavirus strain homotypic to the challenge virus (MO strain) was administered in the mice, complete protection against rotavirus infection was achieved. On the other hand, with oral administration of IgY against a heterotypic strain (serotype 1, Wa strain), a lower protective effect was nevertheless obtained. The four different strains of human rotavirus (Wa, KUN, MO, and ST3) were inactivated in vitro by treatment with PSK, a protein-bound polysaccharide preparation, in a dose-dependent manner. Oral administration of 2.5 mg of PSK caused a therapeutic effect on experimentally MO-infected suckling mice. The antiviral effect of PSK was indicated by the reduction of the duration of diarrhea.     

Development of a Heterologous Model in Germfree Suckling Rats for Studies of Rotavirus Diarrhea

Germfree suckling rats were infected with an SA11 rotavirus strain. Infected pups developed diarrhea associated with histopathological changes. The virus was detected in feces and in the small intestine. Cellular vacuolation was observed in the villi of the jejunum. These results provide a new model for further investigations of group A rotavirus infection.     

Protection against rotavirus diarrhoea in mice by trypsin inhibitor

To investigate the role of soyabean trypsin inhibitor (TI) during rotavirus (RV) diarrhoea, changes in enzyme activities of six relevant mucosal enzymes (lactase, sucrase, maltase, trehalase, glucoamylase and alkaline phosphatase) were assayed following inoculation of suckling mice with EB rotavirus (serotype 3) along with the TI and compared with the age-matched healthy control mice. The animals were divided into three groups i.e. group 1 (controls), group 2 (RV inoculated) and group 3 (RV + TI inoculated and sacrificed under light anaesthesia on 0, 1, 3, 5, 7 and 10 day post inoculation (dpi). Then intestines were excised and divided into two parts (jejunum and ileum). They were separately homogenized in 0.9% cold normal saline and activities of mucosal enzyme were measured. Alkaline phosphatase and disaccharidases were found to be decreased significantly in RV inoculated animals in both the anatomical portions of small intestine of mice. These enzyme levels were restored with the administration of TI i.e. in group 3 and became comparable to the controls in both intestinal portions. These studies suggest that activity of intestinal enzymes which are important in digestive absorptive functions of small intestine were restored with the addition of TI whengiven to infant mice showing its protective efficacy during rotavirus infection.     

Mycobacterium avium subspecies paratuberculosis triggers intestinal pathophysiologic changes in beige/scid mice

We investigated whether infection of beige/scid mice with Mycobacterium avium subspecies paratuberculosis can induce intestinal pathophysiologic changes. Six-week-old beige/scid mice were inoculated intraperitoneally with M. paratuberculosis, then were killed 32 weeks after inoculation when the small intestine was evaluated for physiologic and morphologic abnormalities. All infected mice developed clinical disease. The lamina propria of the intestine from infected mice was mildly infiltrated with mononuclear cells containing acid-fast bacteria, and had significantly increased villus width. In vitro physiologic studies in Ussing chambers indicated that M. paratuberculosis infection caused significant abnormalities in intestinal transport parameters. Baseline short circuit current and potential difference were abnormally high in tissues from infected, compared with control mice, indicative of increased ion secretion. Baseline conductance was significantly decreased in infected mice, suggesting that intestinal tissue from infected mice was less permeable to ions. The change in short circuit current following transmural electrical and glucose stimulation was significantly reduced in intestines from infected mice, suggesting that inflamed intestine had neural and/or epithelial cell damage. We conclude that infection of beige/scid mice with M. paratuberculosis triggers significant intestinal pathophysiologic changes consistent with chronic inflammation. These functional abnormalities may contribute to the pathogenesis of the wasting syndrome seen in bovids with paratuberculosis. This animal model provides evidence that T cell-independent mechanisms are sufficient to cause mucosal pathophysiologic changes and inflammation in response to a specific pathogen, and may be of relevance to inflammatory bowel disease in humans.