胸腺基质淋巴细胞生成素对小鼠巨噬细胞抗原提呈功能及炎性分泌功能的影响

目的:研究胸腺基质淋巴细胞生成素(TSLP)对小鼠巨噬细胞抗原提呈能力及炎性分泌功能的影响和可能作用机制。方法:分离野生型C57B小鼠及TSLPR基因敲除(TSLPR-/-)C57B小鼠腹腔巨噬细胞,给予TSLP进行刺激。采用流式细胞术检测巨噬细胞MHCⅡ、CD86的表达;采用实时定量PCR以及ELISA方法检测小鼠巨噬细胞内以及培养上清液炎症因子MCP-1、TNF-α和IL-10的表达。结果:与野生型对照组比较,野生型实验组小鼠巨噬细胞表面抗原提呈分子(MHCⅡ,CD86)表达明显升高,炎症因子MCP-1和TNF-α表达及分泌均增高,IL-10表达及分泌无明显变化;与TSLPR基因敲除对照组相比较,TSLPR基因敲除小鼠巨噬细胞经TSLP刺激后细胞表面抗原提呈分子(MHCⅡ,CD86)表达及炎症因子MCP-1、TNF-α和IL-10的表达及分泌均无明显变化;与野生型实验组相比较,TSLPR基因敲除可明显抑制TSLP诱导的小鼠巨噬细胞抗原提呈分子增加以及炎症因子表达。结论:TSLP可通过与TSLPR结合促进小鼠巨噬细胞活化,增加巨噬细胞抗原递呈能力,产生炎症因子,促使小鼠巨噬细胞向促炎巨噬细胞表型M1型转化。     

Egr-1基因转染对糖尿病小鼠肾脏炎症反应的影响

目的:观察Egr-1基因转染对糖尿病小鼠肾组织肿瘤坏死因子α(TNF-α)及细胞间黏附分子1(ICAM-1)表达的影响,探讨Egr-1在糖尿病肾病发病机制中的作用。方法:制备糖尿病小鼠模型,成模后随机选取10只作为糖尿病组,剩余40只每周1次经尾静脉分别注射空质粒、Egr-1表达质粒和Egr-1 siRNA质粒,并设立正常对照组。实验共4周,于第4周末收集各组小鼠肾组织标本,分别应用western blot和免疫组织化学染色测定肾组织中Egr-1、TNF-α和ICAM-1的表达;应用电镜观察肾小球超微结构的改变。结果:糖尿病小鼠肾组织Egr-1、TNF-α及ICAM-1表达增强,基底膜普遍增厚,系膜区基质增多,上皮细胞足突融合;Egr-1基因转染后上述变化趋势更加显著。siRNA质粒转染组上述变化较糖尿病组明显减轻。结论:Egr-1可上调TNF-α及ICAM-1表达,促进系膜细胞增殖及系膜外基质积聚,可能是加速肾小球硬化的可能机制之一。     

清胰汤对L-精氨酸诱发的重症急性胰腺炎小鼠胰腺p-STAT3表达的影响

目的: 观察L-精氨酸(L-Arg)诱发的重症急性胰腺炎小鼠胰腺组织p-STAT3表达的变化,以及清胰汤对p-STAT3表达的影响,从而探讨STAT3在急性胰腺炎中的作用和清胰汤治疗急性胰腺炎的机制。方法: 健康雄性成年昆明种小鼠30只,随机分为3组(n=10):对照组、模型组和清胰汤组。除对照组外,其余各组给予腹腔注射20 % L-精氨酸(3 g/kg,间隔1 h再注射1次);清胰汤组在第2 次腹腔注射20 %L-Arg 30 min 后给予清胰汤浓缩液灌胃(10 mL/kg),之后每天灌胃2次。在造模后72 h麻醉处死动物检测血清淀粉酶活性;取胰腺组织计算胰腺湿重比,HE染色观察胰腺病理学改变;取肺组织匀浆检测髓过氧化物酶(MPO)的活性,HE染色观察肺病理学改变; Western blotting及real-time PCR分别检测胰腺组织p-STAT3蛋白及单核细胞趋化蛋白-1(MCP－1)mRNA的表达变化。结果: L-Arg诱发急性胰腺炎72 h后,血清淀粉酶活性明显升高、胰腺湿重比增加、肺组织MPO显著增加,与对照组比较差异显著(P<0.05);而清胰汤组血清淀粉酶的活性、胰腺湿重比、MPO水平明显降低,与模型组相比差异显著(P<0.01);模型组72 h胰腺及肺可见明显病理损伤,胰腺组织p-STAT3蛋白及MCP-1 mRNA的表达明显增强;清胰汤治疗组胰腺及肺病理损伤减轻,胰腺组织p-STAT3蛋白及MCP-1 mRNA的表达减少。结论: L-Arg诱发的重症急性胰腺炎小鼠胰腺组织STAT3蛋白表达明显增加,STAT3活化可能参与了L-Arg诱发的急性胰腺炎进展;抑制胰腺STAT3活化是清胰汤治疗急性胰腺炎的作用机制之一。     

N-乙酰半胱氨酸对重症急性胰腺炎大鼠肺损伤作用的实验研究

目的:探讨N-乙酰半胱氨酸(NAC)对重症急性胰腺炎(SAP)大鼠肺损伤的作用。方法:雄性SD大鼠30只,随机分为假手术组(SO组)、SAP组、NAC组。胆胰管逆行注射5%牛磺胆酸钠制备SAP模型,造模后30min腹腔注射5%NAC(0.2ml/100g)干预SAP模型,12h后处死大鼠。检测各组血清淀粉酶(AMY)、肺组织髓过氧化物酶(MPO)、胰腺和肺组织病理学评分、肺组织肿瘤坏死因子-α(TNF-α)和细胞间粘附分子-1(ICAM-1)mRNA表达的变化。结果:与SO组比较,SAP组AMY、MPO、胰腺和肺组织病理学评分明显升高(P<0.01),TNF-α和ICAM-1mRNA表达明显增强(P<0.01);应用NAC处理后,AMY和MPO水平下降,胰腺和肺组织损伤缓解,TNF-α和ICAM-1mRNA表达减弱,与SAP组有明显差异(P<0.01)。结论:NAC对SAP大鼠肺损伤具有保护作用,其机制可能与抑制肺组织TNF-α和ICAM-1mRNA的表达有关。     

流体剪切力调节内皮细胞组织因子表达的初步探讨

目的探讨流体剪切力调节内皮细胞组织因子(tissue factor,TF)表达的机制。方法将脐静脉内皮细胞置于平行板流动腔中接受1．2 Pa(1 dyn／cm2=0．1 Pa)剪切力作用20 min后,采用凝胶电泳迁移率改变法(electorohoretic mobility shift analysis,EMSA)和蛋白免疫印迹分析(Western Blot,WB)检测转录因子Egr-1和Sp1在TF基因表达过程中的表达情况。结果 (1)静止组可见Sp1表达而无Egr-1表达;(2)剪切力组Sp1磷酸化水平和Egr-1表达水平均明显增高;(3)EMSA显示,对于Sp1／Egr-1结合位点,Egr-1对Sp1具有较强的竞争抑制作用。结论流体剪切力调节TF基因表达过程中,不同转录因子起着不同的作用:Sp1主要维持内皮细胞TF基因的基础表达;Egr-1竞争靶位点上的Sp1和磷酸化Sp1可能共同参与流体剪切力诱导TF基因表达。     

人肝癌及相关组织中Egr—1基因的转录表达及其意义

目的：探讨Egr-1在肝癌癌变过程中的作用。方法：采用原位杂交和免疫组化技术,检测了肝癌及相关组织中Egr-1的mRNA转录水平和蛋白表达,以人乳腺和小鼠肝及大脑组织为对照。结果：在肝癌组织和正常肝组织中,Egr-1的转录水平明显减低或无转录信号;癌旁组织如肝癌癌旁的异型增生（LCD）和“萎缩样肝索”中Egr-1的转录水平明显增高。Egr-1基因在肝癌组织的表达与mRNA检测结果基本一致。在乳腺及小鼠脑组织Egr-1的表达明显增高。结论：Egr-1在肝癌中的缺失表达可能在其癌变过程中正常生长失调方面起作用;Egr-1在正常肝、乳腺及细胞中的表达差异可能与这些细胞的增殖、分化状态及细胞类型特异性有关。     

抗B7-H3单克隆抗体抑制雨蛙肽诱导的小鼠急性胰腺炎炎症反应和组织损伤

目的探究抗B7-H3单克隆抗体(m Ab)在雨蛙肽诱导的急性胰腺炎(AP)中的作用。方法将小鼠随机分为对照组、AP组、抗B7-H3 m Ab治疗组。采用腹腔注射雨蛙肽的方法制备小鼠AP模型,治疗组于造模前1 h皮下注射抗B7-H3 m Ab,于造模后6、12、24 h,收集各组小鼠血液、胰腺及肺组织。采用Western blot法和免疫组织化学染色检测对照组及AP组小鼠胰腺组织B7-H3蛋白表达。应用全自动生化免疫分析仪检测各组小鼠血清淀粉酶及脂肪酶活性;胰腺组织湿干比评估各组小鼠胰腺组织水肿变化;HE染色评估各组小鼠胰腺及肺组织病理变化,利用ELISA检测各组小鼠血清中肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)、IL-1β水平。结果 B7-H3蛋白在AP模型小鼠胰腺组织高表达,且在12 h左右达到高峰;AP组血清淀粉酶及脂肪酶明显高于对照组,抗B7-H3 m Ab处理后明显降低;AP组胰腺及肺组织出现明显炎症反应,治疗组炎症反应明显减弱,胰腺组织湿干比大幅降低;AP组TNF-α、IL-6、IL-1β水平随时间延长而升高,12 h达到高峰后开始下降,而治疗组促炎因子水平相对降低。结论 B7-H3在雨蛙肽诱导的AP模型中存在高表达,抗B7-H3 m Ab可以减弱炎症反应,缓解胰腺及肺组织的损伤。     

Megsin基因转染对糖尿病小鼠肾脏炎症反应的影响及其机制研究

目的观察megsin基因转染对糖尿病小鼠肾组织单核细胞趋化蛋白-1(MCP-1)及细胞间黏附分子-1(ICAM-1)表达的影响,探讨megsin在糖尿病肾病发病机制中的作用。方法制备糖尿病小鼠模型,成模后随机选取10只作为糖尿病组(B组),剩余30只每周1次经尾静脉分别注射空质粒(C组),megsin表达质粒(D组),并设立正常对照组(A组)。实验共4周,于第4周末收集各组小鼠肾组织标本,分别应用Western blot和免疫组织化学染色测定肾组织中megsin、MCP-1、ICAM-1的表达;应用电镜观察肾小球超微结构的改变。结果糖尿病小鼠肾组织megsin、MCP-1及ICAM-1表达增强,基底膜普遍增厚,系膜区基质增多,上皮细胞足突融合;megsin基因转染后上述变化趋势更加显著。结论 megsin可上调MCP-1及ICAM-1表达,促进系膜细胞增殖及系膜外基质积聚,是加速肾小球硬化的可能机制之一。     

清胰汤Ⅱ号冲剂对急性胰腺炎小鼠的保护作用及机制

目的:探讨清胰汤Ⅱ号冲剂(QYT)对急性胰腺炎(acute pancreatitis,AP)小鼠的保护作用及机制。方法:成年C57BL/6小鼠24只,雌雄各半,随机均分为3组。AP组和AP+QYT组首先经腹腔注射雨蛙肽(50μg/kg)及脂多糖(10 mg/kg)复制重症AP模型,AP组小鼠给予饮用水灌胃,AP+QYT组给予QYT灌胃;正常对照组小鼠给予等量生理盐水注射及饮用水灌胃。于末次注药后3 h麻醉处死动物。检测和分析胰腺组织的病理改变、肠道细菌总数和分类、Peyer’s结T淋巴细胞亚群的变化、血浆淀粉酶、白细胞介素6(IL-6)、单核细胞趋化蛋白1(MCP-1)水平以及胰腺和肺脏组织髓过氧化物酶(MPO)活性等。结果:与对照组相比,AP小鼠的胰腺组织病理学评分、肠道细菌数量、血浆淀粉酶活性、IL-6及MCP-1水平、胰和肺组织的MPO活性都有明显升高(P0.05);QYT可在一定程度上逆转AP时相关指标的变化(P0.05)。小肠Peyer’s结数量在各组无明显差异,但AP组的CD3+T淋巴细胞百分比较对照组明显降低(P0.05),而且,AP组和AP+QYT组,尤其是后者CD4+T淋巴细胞百分比和CD4+/CD8+比值较对照组明显升高(P0.05)。结论:清胰汤II号冲剂对雨蛙肽和脂多糖诱导的小鼠急性胰腺炎具有明显的拮抗作用,其机制可能与其抑制炎症反应、促进肠内细菌的清除和调节肠道T淋巴细胞功能有关。     

生长抑素联合大柴胡汤对重症急性胰腺炎大鼠的作用

目的:建立重症急性胰腺炎大鼠模型,研究生长抑素(奥曲肽)联合大柴胡汤对急性重症胰腺炎的作用及初步机制。方法:50只大鼠随机分为假手术组、模型组、奥曲肽组、大柴胡汤组与联合组,经相应处理后记录腹水量,测定血清中淀粉酶(amylase,AMY)、丙氨酸氨基转移酶(alanine aminotransferase,ALT)和肌酐(creatinine,Cr)的水平,HE染色后观察胰腺组织形态,Western blot检测胰腺细胞核中NF-κB与细胞中IκBα的蛋白表达水平,qPCR检测胰腺细胞中ICAM-1与IL-1的mRNA表达水平。结果:生长抑素联合大柴胡汤能有效降低重症急性胰腺炎大鼠的腹水量以及血清中AMY、ALT和Cr的水平;重症急性胰腺炎可导致胰腺细胞核NF-κB蛋白表达升高,IκBα蛋白表达降低,ICAM-1和IL-1 mRNA表达升高。生长抑素联合大柴胡汤可逆转这些改变。结论:生长抑素联合大柴胡汤可以减轻大鼠的急性重症胰腺炎,其机制可能与抑制NF-κB信号通路以及ICAM-1和IL-1表达有关。     

Influence of gender and interleukin-10 deficiency on the inflammatory response during lung infection with Pseudomonas aeruginosa in mice

Cystic fibrosis females have a worse prognosis compared to male patients. Furthermore, cystic fibrosis patients infected with Pseudomonas aeruginosa have been shown to have dysregulated cytokine profiles, as higher levels of tumour necrosis factor alpha (TNF-alpha), interleukin (IL)-8, and lower levels of IL-10 are found in the bronchoalveolar lavage fluid compared to healthy controls. The present study was aimed at investigating the importance of gender and IL-10 in the susceptibility of C57BL/6 mice to pulmonary infection with Pseudomonas aeruginosa. We found that wildtype females were more susceptible than males to infection, as we observed greater weight loss, higher bacterial load, and inflammatory mediators in their lungs. IL-10 knockout mice, both females and males, had higher levels of TNF-alpha in the lungs compared to wildtype mice and maintained higher levels of polymorphonuclear cells and lower levels of macrophages for a longer period of time. Our results demonstrate that the number of bacteria recovered from the lungs of IL-10 knockout male mice was significantly higher than that observed in their wildtype male counterparts and we show that neutralization of IL-10 in infected female mice for a prolonged period of time leads to increased susceptibility to infection. Results reported in this study clearly demonstrate that females, both wildtype and IL-10 knockout mice are more susceptible to Pseudomonas aeruginosa infection than males, and that they mount a stronger inflammatory response in the lungs.     

Neurokinin-1 receptor antagonist treatment protects mice against lung injury in polymicrobial sepsis

Earlier work from our laboratory has suggested a role for the neuropeptide substance P (SP) in inducing lung injury in sepsis. In that study, mice lacking the preprotachykinin-A gene, which encodes for SP, were protected against lung injury in sepsis. To further substantiate the role of SP in sepsis and to study its mechanism, we have evaluated the effect of SR140333, a SP receptor antagonist, on lung injury in sepsis, which was induced in male Swiss mice by cecal ligation and puncture (CLP). Sham-operated animals received the same surgical procedure, except CLP. Vehicle or SR140333 (1 mg/kg, s.c.) was administered to CLP mice 30 min before or 1 h after the CLP. Eight hours after surgery, lung tissue was collected and analyzed for myeloperoxidase (MPO) activity, chemokines, cytokines, and adhesion molecules. The CLP procedure alone caused a significant increase in the lung levels of MIP-2, MCP-1, IL-1beta, IL-6, ICAM-1, E- and P-selectin, and MPO activity when compared with sham-operated mice. SR140333 injected 30 min before or 1 h after CLP significantly attenuated the increased lung MPO activity and levels of MIP-2, MCP-1, IL-1beta, IL-6, ICAM-1, and E- and P-selectin compared with CLP-operated mice injected with the vehicle. Histological evaluation of the lung sections further supported the beneficial effect of SR140333 on lung inflammation. Therefore, SP receptor antagonism can be a potential therapeutic target in polymicrobial sepsis, and this effect is brought about via reduction in leukocyte recruitment.     

后处理对缺血再灌注损伤大鼠肺Egr-1和IL-1β表达的影响

目的: 研究后处理对在体缺血再灌注损伤大鼠肺早期生长反应因子1(Egr-1)和白细胞介素1β(IL-1β)表达的影响,并分析其可能的肺保护作用机制。方法: 建立大鼠在体肺脏缺血再灌注损伤模型,将SD大鼠24只随机分为假手术(sham)组、缺血再灌注(I/R)组和缺血后处理(IPostC)组,每组8只。在体鼠I/R损伤模型制备完成后,阻断左肺门,终止血供及通气,造成左肺缺血,达预定时间后松开阻断带恢复血供及通气形成再灌注损伤。sham组只游离左侧肺门、套阻断带但不阻断,等待3 h后直接取标本;I/R组缺血1 h后再灌注2 h;IPostC组缺血1 h后给予重复3次的5 min灌注和5 min缺血的后处理,继以恢复血供行再灌注1.5 h。3组实验结束后均留取左侧肺组织,制成10%的组织匀浆,用于测定髓过氧化物酶(MPO)的含量;留取小块肺组织测定肺湿／干重比(W/D),并在光镜下观察肺组织的病理变化;RT-PCR法检测Egr-1 mRNA及IL-1β mRNA的表达量。结果: 3组间各项检测指标比较,差异均显著(P<0.05)。与sham组比较,I/R组肺组织中Egr-1 mRNA、IL-1β mRNA的表达量、MPO的活性及W/D值均明显升高(P<0.05);肺组织炎症反应明显加重。IPostC组肺组织中Egr-1 mRNA及IL-1β mRNA的表达量、MPO的活性及W/D值与I/R组相比均明显下降(P<0.05);肺组织炎症反应明显减轻。结论: 后处理能够明显减轻大鼠肺缺血再灌注损伤,其机制可能与抑制Egr-1和IL-1β的表达有关。     

腺苷A2A受体激动剂CGS21680对脂多糖诱导的小鼠急性肺损伤的保护作用

 目的：探讨腺苷A2A受体激动剂对脂多糖(LPS)诱导的急性肺损伤（ALI）小鼠的作用。方法：采用LPS（10 mg/kg）气管内注射6 h后的ALI小鼠模型。实验动物随机分为生理盐水对照组、ALI组、CGS21680治疗组和CGS21680对照组。测定各组6 h后肺湿重/干重比值（W/D）。比色法测定各组肺组织中髓过氧化物酶(MPO)活性。Western blotting分析各组肺组织中细胞间黏附分子1（ICAM-1）和血管细胞黏附分子1（VCAM-1）的表达。酶联免疫吸附法（ELISA）检测各组小鼠血清中单核细胞趋化蛋白1（MCP-1）的浓度。观察各组肺组织病理改变。结果：ALI组肺W/D、MPO活性、ICAM-1及VCAM-1表达和MCP-1浓度均较对照组显著升高。CGS21680治疗组前述各项指标较ALI组有显著下降。CGS21680组较对照组各项指标无显著差异。肺组织病理显示,ALI组可见肺间质明显充血水肿,大量炎症细胞浸润,部分肺泡腔内可见红细胞。CGS21680治疗组可显著改善肺组织的病理变化。结论：腺苷A2A受体激动剂CGS21680可明显减轻LPS诱导的ALI小鼠肺组织的炎症反应及肺组织水肿,提示腺苷A2A受体激动剂在急性肺损伤中具有保护作用。     

Enhanced viral clearance in interleukin-18 gene-deficient mice after pulmonary infection with influenza A virus

T helper 1 driven immune responses facilitate host defence during viral infections. Because interleukin-18 (IL-18) mediates T helper 1 driven immune responses, and since mature IL-18 is up-regulated in human macrophages after influenza virus infection in vitro, it has been suggested that IL-18 plays an important role in the immune response to influenza. To determine the role of IL-18 in respiratory tract infection with influenza, IL-18 gene-deficient (IL-18(-/-)) and normal wildtype mice were intranasally inoculated with influenza A virus. Influenza resulted in an increase in constitutively expressed IL-18 in the lungs of wildtype mice. The clearance of influenza A was inhibited by IL-18, as indicated by reduced viral loads on day 8 and day 12 after infection in IL-18(-/-) mice. This enhanced viral clearance correlated with increased CD4(+) T-cell activation in the lungs as reflected by CD69 expression on the cell surface. Surprisingly, interferon-gamma (IFN-gamma) levels were similar in the lungs of IL-18(-/-) mice and wildtype mice. Intracellular IFN-gamma staining revealed similar expression levels in lung-derived natural killer cells, CD4(+) and CD8(+) T cells, indicating that IFN-gamma production is IL-18-independent during influenza virus infection. Tumour necrosis factor-alpha production by CD4(+) T cells was significantly lower in IL-18(-/-) mice than in wildtype mice. Our data indicate that endogenous IL-18 impairs viral clearance during influenza A infection.     

Intracoronary delivery of DNAzymes targeting human EGR-1 reduces infarct size following myocardial ischaemia reperfusion

Despite improvements in treatment, myocardial infarction (MI) remains an important cause of morbidity and mortality. Inflammation arising from ischaemic and reperfusion injury is a key mechanism which underpins myocardial damage and impairment of cardiac function. Early growth response-1 (Egr-1) is an early immediate gene and a master regulator that has been implicated in the pathogenesis of ischaemia-reperfusion (IR) injury. This study sought to examine the effect of selective inhibition of Egr-1 using catalytic deoxyribonucleic acid molecules (DNAzymes, DZs) delivered via the clinically relevant coronary route in a large animal model of myocardial IR. It was hypothesized that Egr-1 inhibition with intracoronary DZ would reduce infarction size by modulating its downstream effector molecules. Egr-1 DZs inhibited the adherence of THP-1 monocytes to IL-1β-activated endothelial cells in vitro and retained its catalytic activity up to 225 min after in vivo administration. In a porcine model of myocardial IR (45 min ischaemia/3 h reperfusion), DZ was taken up in the cytoplasm and nuclei of cardiomyocytes and endothelial cells in the myocardium after intracoronary delivery. Egr-1 DZs reduced infarct size and improved cardiac functional recovery following intracoronary delivery at the initiation of IR in this large animal model of MI. This was associated with inhibition of pro-inflammatory Egr-1 and ICAM-1 expression, and the reduced expression of TNF-α, PAI-1, TF, and myocardial MPO activity in tissue derived from the border zone of the infarct. Taken together, these data suggest that strategies targeting Egr-1 via the intracoronary route after IR injury in pigs have potential therapeutic implications in human MI.     

Novel chemokine responsiveness and mobilization of neutrophils during sepsis

Blood neutrophils (PMN) are usually unresponsive to CC chemokines such as monacyte chemotactic protein-1 and macrophage inflammatory protein-1 alpha. In rodents, the lung buildup of PMN as determined by myeloperoxidase (MPO) activity after airway instillation of bacterial lipopolysaccharide (LPS) was independent of MCP-1 and MIP-1 alpha. In striking contrast, during sepsis following cecal ligation and puncture (CLP), blood PMN demonstrated mRNA for CC chemokine receptors. Furthermore, PMN from CLP, but not from sham rodents, bound MCP-1 and MIP-1 alpha and responded chemotactically in vitro to both MCP-1 and MIP-1 alpha. In CCR2(-/-) mice or WT mice treated in vivo with antibodies to either MCP-1 or MIP-1 alpha, MPO activity was greatly attenuated in CLP animals. In CLP mice, increased serum IL-6 levels were found to be dependent on CCR2, MCP-1, and MIP-1 alpha. When PMN from CLP rodents were incubated in vitro with either MCP-1 or MIP-1 alpha, release of IL-6 was also shown. These findings suggest that sepsis fundamentally alters the trafficking of PMN into the lung in a manner that now engages functional responses to CC chemokines.     

Monocyte chemoattractant protein 1 contributes to an adequate immune response in influenza pneumonia

Monocyte chemoattractant protein 1 (MCP-1) and its receptor CCR2 have been shown to play an import role in leukocyte recruitment to sites of infection and inflammation. To investigate the role of MCP-1 during infection with influenza we inoculated wild-type (WT) and MCP-1 knockout (KO) mice with a non-lethal dose of a mouse adapted strain of influenza A. Influenza infection of WT mice resulted in a profound increase in pulmonary MCP-1 levels. MCP-1 KO mice had enhanced weight loss and did not fully regain their body weight during the 14-day observation period. In addition, MCP-1 KO mice demonstrated elevated viral loads 8 days after infection, which was accompanied by reduced leukocyte recruitment into the infected lungs, primarily caused by a diminished influx of macrophages and granulocytes. Moreover, pulmonary levels of IgA were reduced in MCP-1 KO mice. The pulmonary concentrations of tumor necrosis factor-alpha, interleukin-6, macrophage inflammatory protein 2 and interferon-gamma were higher in MCP-1 KO mice. This study shows that MCP-1 contributes to an adequate protective immune response against influenza infection in mice.