MEKK3信号通路在炎症和免疫应答中的研究

有丝分裂原活化蛋白激酶激酶激酶3(MEKK3)是MAP3K超家族MEKK/STE11亚群中的一种丝氨酸/苏氨酸蛋白激酶。在一定条件下MEKK3能够活化多种下游MAPK,包括细胞外信号调节激酶(ERK)~(1/2)、c-Jun氨基末端激酶(JNK)、p38以及ERK5。MEKK3组成性地表达于固有免疫细胞和适应性免疫细胞,在免疫应答过程中以及免疫细胞发育、分化、活化和存活过程中起着重要的调节作用。MEKK3不仅参与调节促炎症细胞因子和Toll样受体(TLR)诱导的IKK/NF-κB活化以及多种下游MAPK活化,还参与调节T细胞稳态、活化和分化过程。本文综述了MEKK3蛋白结构、磷酸化与活化机制,及其在炎症和免疫应答中参与调节的信号通路,特别是对促炎因子和TLR引起的固有免疫应答和T细胞表面受体(TCR)介导的适应性免疫应答中信号通路的调节作用。     

rIL-2对T细胞CD69、CD137和CD28表达的影响

T细胞的活化是体内特异性免疫应答的重要环节,且T细胞的活化需双信号刺激。起始信号可使T淋巴细胞初步活化,共刺激信号的存在使初步活化的T淋巴细胞进入完全活化状态,发挥免疫效应,本研究用流式细胞仪检测健康人PBMC经rIL 2刺激后对T细胞及其亚群活化和共刺激信号分子表达的影响。1　材料与方法1 1　主要试剂、仪器　CD4CD6 9CD3、CD8CD6 9CD3、γ1FITC/γ1PE/CD3PerCP单克隆抗体(BD公司)。CD3、CD8单克隆抗体(ExcellenceeBioscience公司)。CD1 37单克隆抗体(Ancell公司)。CD2 8单克隆抗体(ExalphaBiologicals公司)。…     

血小板生成素对体外人血小板活化的影响

目的: 研究血小板生成素(TPO)及其他造血生长因子在体外对人血小板活化的影响。方法:应用荧光标记单克隆抗体和流式细胞技术。结果:终浓度120 ng/mL的TPO在体外能直接诱导人血小板活化,活化率为8.89%~39.92%,中位数17.43%,40 ng/mL的较低浓度TPO及100 ng/mL粒细胞-巨噬细胞集落刺激因子(GM-CSF)和白细胞介素-3(IL-3)对血小板活化无影响。结论:TPO对血小板功能有促进作用,较高浓度的TPO可直接诱导血小板活化。     

未知酪氨酸激酶对骨髓瘤细胞中IL—6诱导Ras／MAPK／NF—IL—6途径活化的调节作用

目的 研究两条主要的IL-6信号转导途径-JAK/STAT和Ras/MAPK/NFG-IL-6在人骨髓瘤细胞系KM-3中的诱导活化情况和调控机制。方法 首先分别采用凝胶阻滞电泳（EMSA）和免疫沉淀（IP）方法检测参与 IL-6信号转导功能的转录因子（STAT3、NF-IL-6）和蛋白激酶（JAK1、MAPK）在KM-3细胞中的诱导活化情况。然后采用特异性酢氨酸蛋白激酶 抑制剂Genistein作用于KM-3细胞,观察酢氨酸磷酸化作用对KM-3细胞中IL-6信号转导功能的影响。结果 IL-6刺激后,KM-3细胞中只出现了Ras/MAPK/NF-IL-6信号转导途径的诱导激活,而JAK/STAT途径则不参与IL-6在KM-3细胞中的信号转导功能。Gwenistein的作用可明显抑制Ras/MAPK/NF-IL-6途径的活化。结论 一种目前尚无法确定的非JAK1酪氨酸蛋白激酶可参与并调节Ras/MAPK/NF-IL-6信号转导途径在KM-3细胞中的诱导活化。     

NO抑制体外IFN-γ刺激成肌细胞/肌管NLRP3炎性小体活化

目的观察一氧化氮供体硝普钠(SNP)、一氧化氮合酶抑制剂(L-NAME)对体外炎性培养(IFN-γ刺激)成肌细胞/肌管NLRP3炎症小体活化的影响。方法利用IFN-γ刺激小鼠C2C12成肌细胞/肌管,q PCR和Western blot分析炎性小体(ASC、NLRP3、caspase-1)的形成及活化、ELISA检测细胞培养上清IL-1β的分泌。进一步利用L-NAME和SNP处理IFN-γ诱导的C2C12细胞/肌管,分析炎性小体的形成、活化及IL-1β的分泌。结果 IFN-γ刺激培养后,成肌细胞/肌管中NLRP3、ASC和mature-caspase-1表达水平上调(P0.01)。较之未刺激的细胞,IFN-γ诱导会显著上调成肌细胞/肌管培养基中的IL-1β浓度(P0.01)。SNP处理后6 h,分化肌管(IFN-γ刺激48 h)内炎性小体(ASC、NLRP3、caspase-1)mRNA和蛋白水平较单纯刺激细胞显著下调(P0.01),L-NAME则上调ASC、NLRP3、caspase-1表达水平(P0.05)。与上述结果一致,SNP和L-NAME处理同时分别下调或上调培养基中IL-1β浓度(P0.05)。结论在炎性条件下,成肌细胞/肌管具备合成并活化NLRP3炎性小体的能力。NO对炎性小体的形成及活化有一定的抑制作用。     

T200类糖蛋白参与人T细胞旁路活化途径

T细胞可通过T细胞受体和CD_2旁路途径活化。为了研究影响T细胞旁路活化途径的细胞表面分子,作者检测了分泌单克隆抗体(McAb)的杂交瘤上清对anti T11_2+anti-T11_3(anti T11_(2/3)刺激的T 细胞旁路活化途径的影响。结果发现,名叫TA/211的McAb 其本身并不激活T 细胞增殖,但能引起亚适量的anti T11_(2/3)刺激T 细胞产生强烈的增殖反应,经免疫沉淀和SDS-聚丙烯酰胺凝胶电泳分析发现,TA/211从静止T 细胞沉淀分子量为180KD、190KD、200KD 和220KD 的四条带上,表明TA/211识别人CD45分子上的共同抗原决定簇。有     

固相PF18-3单抗促进亚适量ConA诱导的胸腺细胞活化后凋亡

目的　研究PF18 3单抗识别分子和胸腺细胞活化及凋亡的关系。方法　应用3H TdR掺入实验及流式细胞术 (FACS)技术 ,分析了胸腺细胞与固相单抗PF18 3共育后细胞活化过程中3H TdR掺入、细胞周期及DNA亚二倍体变化、早期活化及凋亡分子的表达。结果　固相单抗PF18 3有弱的促胸腺细胞3H TdR掺入和促进CD2 5的表达 ,当有亚适量ConA存在时作用更明显。与对照组相比 ,PF18 3及亚适量ConA共育后 ,2 4、48h时活细胞数量减少。细胞周期分析 ,G0 /G1期细胞相对减少 ,S期相对增多 ,但G2 /M期无明显变化。凋亡相关分析 ,共育后 2 4、48h时DNA亚二倍体阳性细胞及 12h时AnnexinV结合阳性细胞增多。结论　PF18 3单抗识别分子能协同亚适量ConA对胸腺细胞的活化 ,并诱导胸腺细胞活化后凋亡     

卵巢癌耐药细胞对活化CD4~+T细胞免疫活性的抑制及其机制

目的探讨卵巢癌顺铂耐药肿瘤细胞对活化CD4~+T细胞的抑制作用及其机制,为卵巢癌耐药患者的免疫治疗提供理论依据。方法用中等浓度间歇作用法建立耐顺铂卵巢癌细胞SKOV3/CDDP,MTT法测定细胞耐药指数及交叉耐药性,流式细胞术(FCM)检测细胞凋亡率。ELISA检测肿瘤细胞培养上清液中TGF-β1、IL-10的含量。抽取正常人外周血用免疫磁珠分离CD4~+T细胞,用CD3和CD28抗体刺激活化CD4~+T细胞。用含20%肿瘤培养上清液培养,ELISA检测CD4~+T细胞IL-2表达量的变化,Western blot检测CD4~+T细胞内NF-κB、Snail的表达变化及肿瘤细胞中TGF-β1、P-smad2/3的表达变化;将肿瘤细胞与活化的CD4~+T淋巴细胞共培养,计数CD4~+T细胞增殖情况,HE染色观察肿瘤细胞对活化CD4~+T细胞黏附的抑制作用。结果SKOV3/CDDP的耐药指数为32.4,对阿霉素、紫杉醇产生交叉耐药性,在CDDP作用下,SKOV3/CDDP凋亡率明显降低。与SKOV3细胞相比,SKOV3/CDDP细胞培养上清TGF-β1表达量升高,SKOV3/CDDP培养上清能抑制活化的CD4~+T淋巴细胞IL-2的表达,抑制CD4~+T淋巴细胞的增殖及黏附作用;Western blot检测显示CD4~+T细胞内NF-κB、Snail的表达降低;SKOV3/CDDP细胞中TGF-β1和P-smad2/3的表达升高(P0.01)。结论 SKOV3/CDDP耐药细胞TGF-β1/P-smad信号通路激活,细胞分泌TGF-β1增多,对活化CD4~+T淋巴细胞的增殖及黏附起抑制作用,可能是通过抑制CD4~+T细胞内的NF-κB/Snail信号通路实现的。     

羧胺三唑对RBL-2H3细胞活化脱颗粒的影响

目的研究羧胺三唑(CAI)对RBL-2H3肥大细胞增殖、凋亡及活化脱颗粒的影响,探索CAI的抗感染作用机制。方法以C48/80诱导RBL-2H3细胞活化脱颗粒模型,中性红染色法观察细胞脱颗粒的形态学,分别用ELISA法和底物显色法检测细胞培养上清中组胺和β-氨基己糖苷酶的释放水平,CCK-8法测定细胞活力,Hoechst 33342荧光染色法检测细胞凋亡。结果与对照组相比,10、20和40μmol/L CAI能够不同程度抑制C48/80诱导的RBL-2H3细胞脱颗粒反应,20和40μmol/L CAI能够降低C48/80诱导的组胺释放(P0.01),40μmol/L CAI能够降低β-氨基己糖苷酶的释放(P0.01)。另外,所用各浓度的CAI对细胞增殖和凋亡均无明显影响。结论 CAI能有效抑制RBL-2H3肥大细胞的活化脱颗粒,此作用并不是通过细胞毒发挥作用的。CAI可能部分通过下调肥大细胞的功能活化,发挥其抗感染作用。     

识别不同结构域的PTA1/CD226的mAb与活化血小板的关系

目的:研究识别不同PTA1/CD226分子结构域的mAb与刺激血小板活化的关系。方法:采用识别不同结构域的抗PTA1/CD226的mAb(FMU17),应用免疫荧光染色、流式细胞术和血小板凝集试验,研究识别不同结构域mAb对血小板的活化作用。结果:识别CD226第1个结构域的3株mAb(FMU1、2和3)可以与血小板结合,并可刺激血小板发生凝集,而识别CD226第2个结构域的mAbFMU6、FMU7以及识别两个结构域之间序列的FMU4和FMU5既不能与血小板表面天然的CD226分子结合,也不能刺激血小板活化。结论:抗PTA1/CD226mAb刺激血小板活化与抗体识别的结构域有关。     

Glutamatergic and gabaergic postsynaptic responses of striatal spiny neurons to intrastriatal and cortical stimulation recorded in slice preparations

Glutamatergic and GABAergic responses of the neostriatal spiny neurons to intrastriatal and cortical stimulation were characterized by intracellular recording in brain slice preparations. This study also demonstrated the role of each response in the spike activity of the spiny neuron. Single neostriatal stimulation induced postsynaptic potentials consisting of multiple components. The early part of the postsynaptic potential, which was isolated by the GABA_A antagonist bicuculline methiodide and the N-methyl-d-aspartate antagonist 3-(2-carboxypiperzin-4-yl)-propyl-1-phosphonic acid (CPP), was mainly an -amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)/kainate receptor-mediated response. Perfusion of magnesium-free medium containing bicuculline methiodide and the AMPA/kainate antagonist 3-dihydroxy-6-nitro-7-sulfamoyl-benzo]f]quinoxaline (NBQX) disclosed a large, slow N-methyl-d-aspartate receptor-mediated response. the N-methyl-d-aspartate response in magnesium-containing perfusing medium was small in neurons at the resting membrane potential, but became a significant component when the neurons were depolarized to subthreshold membrane potential. The duration of the N-methyl-d-aspartate response was over 300 ms. The nicotinic antagonists dihydro-β-erythroidine hydrobromide and mecamylamine failed to change responses to single stimulation.

Repetitive intrastriatal stimulation induced a large, long-duration depolarization with action potentials in the spiny neurons. This stimulation-induced response resembles that of the depolarization stage observed in anesthetized animals. Bicuculline methiodide increased the response amplitude. In contrast, CPP reduced the amplitude of the response to the below the spike generation threshold. The CPP-sensitive N-methyl-d-aspartate response was large and lasted several hundred milliseconds after the termination of repetitive stimulation. Responses of the neostriatal neurons to cortical stimulation were similar to those induced after intrastriatal stimulation. CPP greatly reduced both the response amplitude and the number of spikes triggered from the response. Bicuculline methiodide, on the other hand, greatly increased the response amplitude and the number of spikes. The AMPA/kainate response alone, which was isolated by application of bicuculline methiodide and CPP, did not induce sustained depolarization in spiny neurons to repetitive cortical stimulation. Application of NBQX diminished GABA_A response to cortical stimulation. This observation indicates that, for neostriatal spiny neurons to respond with GABA_A response after cortical stimulation, the AMPA/kainate response must be induced in the GABAergic secondary neurons in the neostriatum.

This study indicates that the main synaptic driving forces of neostriatal spiny neurons include AMPA/kainate, N-methyl-d-aspartate and GABA_A responses. Although AMPA/kainate response is the main synaptic input, the generation of the action potentials in neostriatal neurons is greatly influenced by both GABA_A and N-methyl-d-aspartate responses.     

Mechanical and electromyographic responses to stretch of the human anterior tibial muscle at different levels of contraction

Summary The EMG response and the mechanical response to 2 degree stretch of the human anterior tibial muscle was studied during contractions ranging from 0% to 80% of maximal voluntary contraction (MVC). The EMG response showed three distinct peaks M1, M2, and M3 with peak latencies of 59 ms, 86 ms, and 120 ms respectively. At low background torques M1 dominated while M2 and M3 were small or absent. M2 and M3 dominated above 40% of MVC and M2 in particular showed automatic gain compensation, i.e. it constituted a — more or less — constant proportion of the background EMG for all contraction levels. The ratio between M1 amplitude and background EMG steadily decreased with contraction level. Even though the summed contributions of M1, M2, and M3 to some degree showed automatic gain compensation, this was not the case for the mechanical response to stretch. Between 0% and 30% of MVC the reflex mediated mechanical response increased approximately in proportion to the contraction level, but the reflex mediated mechanical response peaked at 40% of MVC and declined to zero at 80% of MVC. This discrepancy between EMG and mechanical response was explained by a simple model. The regression line between rectified and filtered tibialis anterior EMG and torque was used to predict the mechanical response from the EMG response. At increasing contraction levels the twitch elicited by supramaximal electrical stimulation decreases, and we reduced the predicted mechanical response by the same factor as the twitch. This simple model predicted the mechanical response for all contraction levels, making it possible to assess the functionality of reflexes even when accurate measurements of muscle force or intrinsic muscle properties are not possible.     

THE HEART RATE RESPONSE TO A BRIEF AUDITORY AND VISUAL STIMULUS

The adult heart rate (HR) response was studied in 18 male subjects following a series of 10 tones and 10 light flashes. Both stimuli were of moderate intensity (54 db and 8.0 ml) and had rise times of 30 milliseconds. The tone evoked a predominantly acceleratory response and no decrement with repetition. Initially, the light flash evoked a predominantly deceleratory response which changed to one of acceleration as the stimulus was repeated. Analysis of respiration revealed that an increase in rate and amplitude followed both stimuli and that the magnitude of respiratory changes did not diminish with stimulus repetition. Viewed according to Sokolov's criteria for identifying orienting, defensive, and adaptive responses the results support the conclusions that: (1) HR deceleration is a component of the orienting response; and (2) HR acceleration is neither an orienting, defensive, nor adaptive response but is largely secondary to respiratory changes. On the basis of the evidence, a tentative model of the HR response to simple auditory and visual stimuli is offered.     

Rapid viral response and treatment outcome in genotype 2 and 3 chronic hepatitis C: comparison between two HCV RNA quantitation methods

Fifty consecutive patients with genotype 2 or 3 chronic hepatitis C were treated with peg-IFN alfa-2a 135 microg weekly and ribavirin (11 mg/kg body weight) daily during 24 weeks. Rapid viral response treatment week 4, end-of-treatment response, and sustained viral response were analyzed by two different HCV RNA quantitation methods, the Cobas Amplicor Monitor test and the TaqMan test with a sensitivity of 600 and 15 IU/ml, respectively. The TaqMan test differentiated patients with rapid viral response finally achieving sustained viral response better. Hence, patients with and without rapid viral response as tested by the TaqMan test finally achieved sustained viral response in 97% (32/33) versus in 75% (12/16), P < 0.017. The corresponding figures for the Cobas Amplicor test was 91% (41/45) versus (80%) 4/5 a non-significant difference. In conclusion, the more sensitive TaqMan test yielded a lower number of patients with rapid viral response than the less sensitive Amplicor Monitor test, but predicted sustained viral response in a higher percentage of patients with rapid viral response than the Amplicor Monitor test. A rapid viral response meaning HCV RNA levels <15 IU/ml predicted a sustained viral response in 97% of patients with genotype 2 or 3.     

Local and peripheral cell-mediated immune response to influenza virus in mice

Presentation of different influenza virus antigens generates different immune responses. Intranasal immunization with either live (VA) or formalin-inactivated (VF) A/PR/8/34 (HON1) influenza virus induced local as well as peripheral cell-mediated immune response (CMI), as evidenced by elevation in 3H-thymidine incorporation. Cell-mediated immune response was detected as soon as 24-48 hr following the application of VA and 4-5 days following VF. Cell-mediated immune response in both instances peaked on the 12th day and disappeared between 16 and 20 days after application. Local CMI response was threefold higher after immunization with VA (SI = 28.6) than with VF (SI = 9.4), while VF induced higher peripheral response (32.0 vs 17.7). The mononuclear cell population in the lungs increased, correlating with a rise in the stimulation index (SI). The percentage of IgA surface-bearing B lymphocytes was significantly higher following IN administration of VA, but not following VF instillation. This corroborated the finding that VF failed to induce local antibody response in the lungs in spite of its capacity to stimulate humoral antibody and CMI responses. Mice immunized intramuscularly with both viral preparations developed a fair humoral antibody response without detectable CMI (peripheral or local).     

Immune-mediated mechanisms of atherosclerosis and implications for the clinic

Introduction: A large body of evidence supports the inflammatory hypothesis of atherosclerosis, and both innate and adaptive immune responses play important roles in all disease stages.

Areas covered: Here, we review our understanding of the role of the immune response in atherosclerosis, focusing on the pathways currently amenable to therapeutic modulation. We also discuss the advantages or undesirable effects that may be foreseen from targeting the immune response in patients at high cardiovascular risk, suggesting new avenues for research.

Expert commentary: There is an extraordinary opportunity to directly test the inflammatory hypothesis of atherosclerosis in the clinic using currently available therapeutics. However, a more balanced interpretation of the experimental and translational data is needed, which may help address and identify in more detail the appropriate settings where an immune pathway can be targeted with minimal risk.     

Fc-Dependent Monoclonal IgG1-Mediated Suppression of Antibody Response

It has been known for a long time that passively administered antibodies (Abs) or immune complexes regulate the immune response to their specific antigen (Ag). IgG may sometimes suppress the humoral immune response against soluble antigens. The exact mechanism behind this phenomenon has not been understood yet and the requirement for the Fc part is still a matter of controversy. The present study was undertaken to clarify whether there is a true IgG-mediated Fc-dependent suppression of the immune response. Antigen and monoclonal antibody (mAb) used in this study were recombinant human interferon gamma (r-hIFN-γ) and mouse monoclonal antibodies specific for human IFN-γ [anti-hIFN-γ mAb (CAy-IFNγ38)] respectively. An intact IgG-free preparation of Fab plus various Fc fragments was prepared from papain-digested CAy-IFNγ38. Ag/IgG and Ag/Fab complexes were prepared at various molar ratios. Keeping the Ag doses constant, mice were immunized either with Ag, Ag/IgG or Ag/Fab complexes. Primary immunization and the boosting were performed with the samples in complete and incomplete Freund's adjuvants respectively. Specific antibody levels were measured by an ELISA. Immunization performed with Ag/Fab complexes even at a molar ratio of 1:1.36 did not result in marked suppression of the response when compared to that of Ag only-immunization. In contrast, Ag/IgG complexes resulted in nearly 90% suppression of the antibody response. Our observations suggest that Fc part of IgG molecule plays a crucial role in suppression of the in vivo antibody response against the Ag when complexed with intact IgG.     

THE CARDIAC RESPONSE TO A PERCEPTUAL COGNITIVE TASK IN THE YOUNG CHILD

It has been argued that an important determinant of the cardiac response is the subject's intended transaction with his environment. The present study was designed to investigate whether cardiac deceleration would accompany the solution of a perceptual discrimination problem, whether the degree of cardiac deceleration would be related to the accuracy of the response, and the relationship between general intellectual ability and the cardiac response to the problem. Fifty-one subjects, 44 months of age, were each given 20 trials of a matching figures task. This task required that S match a figure (called standard) to one of four variations (one of which was identical to the standard). EKG was continuously recorded along with the latency and the accuracy of the response. If the first response was incorrect, S was asked to choose again. The results indicated: (1) There was a significant cardiac deceleration from the time S received the standard until he made his first choice. If the first response was correct, the cardiac rate, within 1–3 beats, returned to resting level; however, if S was told to guess again, the cardiac rate remained decelerated. (2) While accuracy of response was found to be related to the cardiac response, the effect was eliminated when response speed was controlled. (3) The degree of cardiac deceleration was correlated with general intellectual function as measured by a standard IQ test; however, it was significant only for girls.     

No increase in response rate by adding a web response option to a postal population survey: a randomized trial

Background

There is substantial interest in use of the Internet for surveys, but there have been few health-oriented, large, randomized trials of general population surveys on the Internet. It is unclear whether providing the option to respond via Internet increases the response rate, and to what degree the results will differ.

Objective

The aim of the study was to evaluate changes in response rate and outcomes in a postal respiratory health survey by adding an optional Web response alternative.

Methods

This was a randomized trial of a random sample of 4213 permanent residents of Norway, aged 20-40 years. Participants were randomized into a traditional survey arm, where they were asked to return the survey by mail, and an arm where they were also offered the option to respond via a Web form.

Results

A total of 1928/4213 subjects responded, a response rate of 45.8% across both arms. The total response rate was 44.8% (944/2105) in the postal plus optional Internet response arm and 46.7% (984/2108) in the usual postal survey arm, with no statistically significant difference between the randomized groups (P = .24). In the optional Internet arm, 8.3% (175/2105) of the sample responded using the Internet and 36.5% (769/2105) responded by post. Thus, Internet response was chosen by 18.5% (175/944) of those who replied in the optional Internet arm. In the multivariate analysis, Internet response was associated with being male, frequency and type of Internet access (home users more likely to respond by Internet than work users), and smoking habit, with current smokers being more likely to be Internet responders. 57% preferred postal response (1102/1928), 38% preferred Internet response (733/1928), and 3% preferred telephone interview (54/1928), with no difference between randomization arms (P = .56). But among those who indicated that they preferred the Internet response and who were randomized to the optional Internet arm, only 47% actually chose the Internet response. Asthma prevalence was higher among participants choosing the Internet response mode (16.7% vs 12.4%).

Conclusions

We failed to increase survey response rates by adding an optional Internet response. Asthma diagnosis was higher in the Internet response group, suggesting nonresponse bias. Method comparison studies should be carried out before Internet studies are accepted in new populations or new subject matters.     

Acute murine H5N1 influenza A encephalitis

Avian influenza A virus H5N1 has the proven capacity to infect humans through cross‐species transmission, but to date, efficient human‐to‐human transmission is limited. In natural avian hosts, animal models and sporadic human outbreaks, H5N1 infection has been associated with neurological disease. We infected BALB/c mice intranasally with H5N1 influenza A/Viet Nam/1203/2004 to study the immune response during acute encephalitis. Using immunohistochemistry and in situ hybridization, we compared the time course of viral infection with activation of immunity. By 5 days postinfection (DPI), mice had lost substantial body weight and required sacrifice by 7 DPI. H5N1 influenza was detected in the lung as early as 1 DPI, whereas infected neurons were not observed until 4 DPI. H5N1 infection of BALB/c mice developed into severe acute panencephalitis. Infected neurons lacked evidence of a perineuronal net and exhibited signs of apoptosis. Whereas lung influenza infection was associated with an early type I interferon (IFN) response followed by a reduction in viral burden concordant with appearance of IFN‐γ, the central nervous system environment exhibited a blunted type I IFN response.