CD4、CD8分子在被动吸烟诱导的肺气肿大鼠中的表达及意义

目的探讨CD4、CD8分子在被动吸烟诱导的肺气肿大鼠中的表达及意义。方法 26只大鼠随机分为2组：正常对照组、肺气肿组。单纯吸烟法建立肺气肿模型,熏烟暴露共计74d。以酶联免疫吸附法（ELISA）测定2组血清和支气管肺泡灌洗液（BALF）中的CD4、CD8分子、肿瘤坏死因子-α（TNF-α）和白介素-8（IL-8）的浓度。肺组织切片行苏木素-伊红染色观察形态学改变,并定量测定肺平均内衬间隔（MLI）、平均肺泡数（MAN）。结果 （1）肺气肿组血清CD4含量、CD4/CD8较正常对照组降低（P〈0.05）;但其BALF中CD4分子含量、CD4/CD8和正常对照组比较,差异无显著意义（P〉0.05）。（2）肺气肿组血清及BALF中TNF-α、IL-8浓度较正常对照组增加（P〈0.05）。（3）肺气肿组MLI比正常对照组增高,MAN比正常对照组降低（P〈0.05）。（4）血清CD4分子和IL-8浓度呈负相关（r=-0.59,P〈0.05）,但和TNF-α浓度无明显相关（r=-0.26,P〉0.05）;血清CD4/CD8和TNF-α、IL-8浓度呈负相关（r分别为-0.51,-0.60,P〈0.05）。结论吸烟肺气肿大鼠可出现全身免疫功能降低,易诱发血清中炎症因子浓度升高。     

Th2相关炎症因子在湿疹发病中的作用机制

湿疹是临床常见的炎症性皮肤病,具有剧烈瘙痒、反复发作等特点。其病因复杂,包括多种内、外因素相互作用。主要发病机制与Th2免疫应答失衡有关,相关的炎症因子更是发挥十分重要的作用。上皮衍生因子胸腺基质淋巴细胞生成素以及白介素-33（IL-33）能够引发Th2免疫失衡,促进IL-4、IL-5、IL-13等炎症因子分泌,后者进一步诱导嗜酸性粒细胞增多、IgE生成。综述Th2相关炎症因子在湿疹发病中的作用机制,对湿疹治疗具有重要意义。     

板蓝根提取物对肺炎支原体感染小鼠血清白介素-6、肿瘤坏死因子-α和白介素-17A的影响研究

目的探讨板蓝根提取物对肺炎支原体感染小鼠血清细胞因子白介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、白介素-17A(IL-17A)水平的影响。方法 选取40只BALB/c小鼠并随机分为对照组、模型组、三种不同浓度（250、125、62.5 mg/ml）板蓝根提取物组,每组8只。采用肺炎支原体标准菌株M19滴鼻法建立肺炎支原体感染小鼠模型。建模成功后灌胃不同浓度的板蓝根提取物,对照组和模型组灌胃等量的生理盐水。苏木精-伊红染色法观察肺组织病理变化,流式法检测小鼠血清IL-6、TNF-α、IL-17A的水平。结果 模型组血清IL-6、TNF-α、IL-17A水平高于对照组;板蓝根低、中、高浓度组IL-6和IL-17A水平均低于模型组,板蓝根中、高浓度组TNF-α水平均低于模型组,差异有统计学意义（P<0.05）。结论 板蓝根能缓解肺炎支原体感染引起的肺组织炎性病变及过量炎症因子IL-6、TNF-α、IL-17A的释放,抑制过度免疫反应,减轻免疫病理损伤。     

结核性胸腔积液病人IL-12、IL-18、TNF-α的水平及变化

目的：探讨三种与结核病（TB）保护性免疫有关的细胞因子白介素-12（IL-12）、白介素-18（IL-18）和肿瘤坏死因子-α（TNF-α）在结核病（TB）免疫发病机制中的作用,为设计新的疫苗和开展辅助性免疫疗法提供依据。方法：检测39例结核性胸腔积液病人胸水中和血清中IL-12、IL-18、TNF-α的水平;并对治疗好转过程中10例Ⅲ型病人和5例Ⅳ型病人这些细胞因子在胸水中的变化进行观测。结果：除IL-18外,其他两种细胞因子胸水中与血清中含量均有显著性差异;IL-12与TNF-α之间有相关关系。治疗好转过程中,Ⅲ型病人绝大多数见IL-12、IL-18水平增高。结论：IL-18用于疫苗佐剂应该优于IL-12;复治组病人IL-12与TNF-α之间呈显著正相关,开展免疫疗法时可参考。     

小剂量地塞米松对新生儿胎粪吸入综合征患儿血清IL-5、IL-13和TNF-α的影响

目的探讨小剂量地塞米松对新生儿胎粪吸入综合征患儿血清中白介素-5（IL-5）、白介素-13（IL-13）和肿瘤坏死因子-α（TNF-α）的影响。方法新生儿胎粪吸入综合征患儿40例,随机分为治疗组和对照组,除了治疗组从第1、2、3天加用小剂量地塞米松[0.5mg/（kg·d）]治疗外,两组其余治疗方案均相同;以足月顺产的正常新生儿20例作为正常组。检测3组研究对象第1、4、7天血清IL-5、IL-13、TNF-α的变化。结果对照组第1、4、7天血清IL-5、IL-13、TNF-α水平均高于正常组（P〈0.05）;对照组和治疗组第4天血清IL-5、IL-13、TNF-α明显升高,且对照组的水平高于治疗组（P〈0.05）。结论在新生儿胎粪吸入综合征患儿治疗过程中,小剂量地塞米松可抑制炎症反应,减轻气道高反应性。     

当归对阴虚哮喘小鼠的平喘作用及肺组织中水通道蛋白5表达的影响

目的 探讨当归对阴虚哮喘小鼠的平喘作用及对肺组织中水通道蛋白5 (AQP5)表达的影响.方法 通过注射卵清白蛋白(OVA)致敏、吸入OVA激发的方法复制哮喘小鼠模型,实验后期给予甲状腺素复制阴虚哮喘模型,观测哮喘发作及其程度、肺功能、肺液清除功能,血清白介素-13(IL-13)、α-肿瘤坏死因子(TNF-α)的水平和肺组织中AQP5及其基因的表达.结果 当归能抑制哮喘发作并缓解其症状,改善肺功能,促进肺组织AQP5及其基因的表达,降低血清IL-13与TNF-α的水平;当归与地塞米松配伍后,对改善肺功能、调节AQP5及其基因表达等有一定的协同作用.结论 当归具有一定的平喘作用,调节AQP5及基因表达进而促进肺组织水代谢平衡是其作用机制之一.     

雷公藤多甙与白介素-10对人外周血树突细胞的影响

目的：体外研究雷公藤多甙与白介素-10（IL-10）对人外周血树突细胞表面HLA-DR、CD80抗原表达及IL-12 p40蛋白表达和mRNA转录的影响。方法：采用GM-CSF、IL-4和TNFα体外培养体系获得人外周血树突细胞（DC）,HLA-DR和CD80抗原的表达经免疫荧光染色后采用流式细胞仪进行分析,用酶联免疫吸附测定和逆转录聚合酶链反应分别检测IL-12 p40蛋白水平和mRNA的转录。结果：雷公藤多甙5-20mg/L显著下调HLA-DR和CD80抗原的表达,IL-10 50-200μg/L能抑制HLA-DR和CD80抗原的表达,并都具有剂量依赖关系;雷公藤多甙5-20mg/L和IL-10 50-200μg/L均能抑制DC分泌IL-12 p40蛋白,同时经雷公藤多甙20mg/L和IL-10 200μg/L处理的DC中IL-12 p40 mRNA的表达受到显著抑制。结论：雷公藤多甙和IL-10能通过抑制DC表面分子的表达和IL-12的合成而发挥免疫抑制作用。     

TNF-α和IL-6在扁平苔藓中的表达和意义

目的检测扁平苔藓患者皮损处肿瘤坏死因子-α（TNF-α）和白介素-6（IL-6）的表达,探讨其在扁平苔藓发病过程中的作用。方法选取30例扁平苔藓组织和30例正常皮肤组织,采用免疫组织化学技术观察TNF-α和IL-6的表达。结果 TNF-α和IL-6在扁平苔藓组中的表达均高于在正常皮肤组中的表达（P〈0.001）且二者在扁平苔藓皮损处的表达呈正相关（r=0.804,P〈0.001）。结论 TNF-α和IL-6的高表达可能参与了扁平苔藓的发病。     

脑梗死继发癫痫患者血清神经烯醇化酶与细胞因子浓度的相关性研究

目的探讨脑梗死继发癫痫患者外周血清神经元特异性烯醇化酶（NSE）与肿瘤坏死因子-α（TNF—α）、白介素-2（IL-2）和白介素石（IL-6）水平变化及其与NSE的关系。方法选择2006年6月至2009年6月收治的脑梗死继发癫痫患者42例和同期单纯脑梗死患者、健康体检者各30例。采用ELISA法测定血清NSE与TNF-α、IL-2和IL-6水平,同步进行美国国立卫生研究院卒中量表（NIHSS）评分,研究患者NSE与TNF-α、IL-2和IL-6水平的关系。结果脑梗死继发癫痫患者血清NSE与TNF-α、IL-2和IL-6水平均明显高于单纯脑梗死患者及健康体检者（P〈0．01）;继发癫痫患者血清NSE与TNF-α、IL-2和IL-6表达水平之间呈正相关（P〈0．01）;血清NSE水平与NIH评分亦呈正相关（P〈0．01）。结论脑梗死继发癫痫患者神经组织损伤严重,免疫系统处于活化状态,细胞因子水平的失衡参与了癫痫的免疫病理过程。     

直肠接种含抗原的微球体诱导的Th2应答强于口腔接种

直肠作为诱生全身和局部免疫应答的有效部位很少引起人们的注意。为了解含卵白蛋白 ( OVA)的微球体 ( MS- OVA)作为一种抗原进行直肠接种能否有效地诱导小鼠产生局部和全身性免疫应答 ,作者分别在 0、7、1 4天给予雌性 BALB/ c小鼠口服或直肠接种磷酸盐缓冲盐水 ( PBS)、空微球 ( MS)、OVA或 MS- OVA。第 1次接种后第 7、1 4、2 1、2 8和 35天收集血样 ,第 35天收集小鼠的粪便提取物 ,用夹心 ELISA法检测血清和粪便OVA特异性 Ig A和 Ig G水平 ,用酶联免疫斑点法 ( EL ISPOT)测定抗原特异性抗体形成细胞 ( AFC) ;从小肠、…     

Nivalenol inhibits total and antigen-specific IgE production in mice

Nivalenol (NIV) has been reported to induce hyperproduction of IgA, which is regulated by T-helper 2 cells (Th2); however, whether IgE production, which is under the regulation of Th2 cells, is induced by this compound remains largely unknown. We examined the effect of NIV on antigen-specific IgE production using ovalbumin (OVA)-specific T cell receptor alphabeta-transgenic mice. The mice produced significant amounts of total and antigen-specific IgE, IgG1, and IgA in serum when given OVA orally. Administration of NIV with OVA suppressed total IgE and OVA-specific IgE, IgG1, and IgA production significantly. Cytokine assay using splenocytes obtained from mice given the OVA plus NIV diet revealed that interleukin 4 (IL-4) production was suppressed and interleuin-2 (IL-2) production was enhanced. These results suggest that the inhibition of IL-4 production and enhancement of IL-2 production induced by NIV suppressed total and antigen-specific IgE production.     

The feeding of beta-carotene down-regulates serum IgE levels and inhibits the type I allergic response in mice

Feed containing beta-carotene was administered orally to BALB/c mice immunized intraperitoneally with ovalbumin (OVA) for approximately 1 month. The titers of OVA-specific IgE, OVA-specific IgG1 and OVA-specific IgG2a in the mouse sera were determined. The OVA-specific IgE titer and OVA-specific IgG1 titer by mice fed beta-carotene were significantly inhibited. On the other hand, the OVA-specific IgG2a titer in mice fed beta-carotene was significantly greater than those of control mice. The OVA-specific IgE suppression of beta-carotene feeding was dose-dependent. We also examined the effect of fed beta-carotene on active systemic anaphylaxis. Feeding beta-carotene to mice immunized with OVA inhibited the immediate reduction of the body temperature induced by antigen stimulation. Furthermore, the increase in serum histamine in the mice fed beta-carotene under active systemic anaphylaxis was lower than in controls. We then examined the pattern of cytokine production by spleen cells from mice followed by restimulation with OVA in vitro. The spleen cells from the mice fed beta-carotene produced more IFN-gamma, IL-12 and IL-2 than those from the control group. In contrast, the spleen cells from the mice fed beta-carotene produced less IL-4, IL-5, IL-6, IL-10 than those from the control group. Furthermore, analysis of IFN-gamma mRNA levels of the splenocytes using the real-time quantitative RT-PCR technique revealed higher levels in the splenocytes from the mice fed beta-carotene. These findings suggest that feeding beta-carotene improves the helper T cell (T(H))1-T(H)2 balance, inhibiting specific IgE and IgG1 production and antigen-induced anaphylactic response.     

CpG ODN mediated prevention from ovalbumin-induced anaphylaxis in mouse through B cell pathway

Allergic inflammation is induced by type 2 T helper cell (Th2) and Th2 cytokines such as interleukin (IL)-4, IL-5 and IL-13. These cytokines induce the production of allergen-specific immunoglobulin (Ig)E by B cells, and the ensuing degranulation of mast cells via IgE cross-linking leads to most clinical manifestations of allergic diseases. We examined the ability of immunomodulatory unmethylated CpG oligodeoxynucleotides (ODN), which are potent inducers of Th1 cytokines, to prevent allergic symptoms in mice immunized and sensitized with allergen. Coadministration of CpG ODN with ovalbumin (OVA) before OVA sensitization substantially prevented mice from allergic anaphylaxis representing enhanced circulating concentrations of OVA-specific IgE and histamine, and decreased body temperature. Although CpG ODN provokes an abundance of Th1-skewing cytokines, including IL-12, interferon (IFN)-alpha and IFN-gamma, administration of CpG ODN in IFN-gamma deficient mice inhibited IgE production and prevented from OVA-induced anaphylaxis, indicating a dispensable role of IFN-gamma in mediating these protective effects. In vitro analysis revealed that CpG ODN inhibited class switching from IgM to IgE and IgG1 in response to CD40 and IL-4 in B cells, and this effect did not correlate with up-regulation of IFN-alpha production. These results imply a B cell-intrinsic, T cell-independent mechanism by which CpG ODN directly acts on B cells and inhibits IgE and IgG1 production leading to cause prevention from allergic symptoms.     

Vaccination with an ovalbumin/interleukin-4 fusion DNA efficiently induces Th2 cell-mediated immune responses in an ovalbumin-specific manner

To more effectively drive immune responses toward antigen-specific T helper type 2 (Th2) cellmediated responses, we constructed a mammalian expression vector (pOVA/IL4) carrying a fused gene in which the ovalbumin (OVA) cDNA was covalently linked to murine interleukin-4 (IL-4) cDNA. A biologically active OVA/IL4 protein was expressed by the transfected COS cells with the pOVA/IL4 DNA, as demonstrated by Western blotting and cytokine bioassay. Intramuscular injection of BALB/c mice with the pOVA/IL4 DNA increased both the production of OVA-specific IL-4 by CD4⁺ T cells and the ratio of anti-OVA IgG1 to anti-OVA IgG2a isotypes, while the injection with the pOVA DNA alone, or with the mixture of the pOVA and plL4 DNA did no or little increase. Furthermore, the OVA-specific, Th2 cell-mediated immune responses were significantly enhanced by multiple injections with the pOVA/IL4 DNA. These studies indicate that the direct linkage of an OVA gene to an IL-4 gene in the expression plasmid confines the effects of IL-4 to the OVA-specific cells, efficiently driving the immune response toward OVA-specific., Th2 cell-mediated responses.     

Possible involvement of suppression of Th2 differentiation in the anti-allergic effect of Sho-seiryu-to in mice

The clinical effectiveness of the Kampo medicine Sho-seiryu-to (SST) has recently been demonstrated in a double-blind randomized study of allergic asthma and rhinitis. We investigated the effect of SST on a type 1 allergic model in mice. Ovalbumin (OVA)-induced sneezing and the total and OVA-specific IgE levels were significantly suppressed with SST at 1.0 g/kg, but that of OVA-specific IgG(2a) was not. In the splenocytes isolated from SST-administered mice, OVA-induced interleukin (IL)-4 production decreased while interferon (IFN)-gamma production was not. The co-culture experiments using purified CD4(+)T cells and antigen-presenting cells (APCs) suggested that SST influenced both cell types. Flow-cytometric analysis showed that SST suppressed the number of IL-4 producing CD4(+)T cells but not the number of IFN-gamma producing CD4(+)T cells. The CD86(+) major histocompatibility complex class II(+) (MHC II)(+) cells and CD28(+)CD4(+)T cells were decreased by SST treatment, while CD80(+)MHC II(+) cells, CD40(+)MHC II(+) cells and CD154(+)CD4(+)T cells showed no change. These data suggested that SST may suppress IL-4 production in CD4(+)T cells via influencing CD28-CD86 interaction. In addition to the previously reported inhibitory activity on histamine release, suppression of Th2 differentiation at the stage of APC-CD4(+)T cell interaction may be involved in the anti-allergic effects of SST.     

Effects of gasoline engine emissions on preexisting allergic airway responses in mice

Gasoline-powered vehicle emissions contribute significantly to ambient air pollution. We hypothesized that exposure to gasoline engine emissions (GEE) may exacerbate preexisting allergic airway responses. Male BALB/c mice were sensitized by injection with ovalbumin (OVA) and then received a 10-min aerosolized OVA challenge. Parallel groups were sham-sensitized with saline. Mice were exposed 6 h/day to air (control, C) or GEE containing particulate matter (PM) at low (L), medium (M), or high (H) concentrations, or to the H level with PM removed by filtration (high-filtered, HF). Immediately after GEE exposure mice received another 10-min aerosol OVA challenge (pre-OVA protocol). In a second (post-OVA) protocol, mice were similarly sensitized but only challenged to OVA before air or GEE exposure. Measurements of airway hyperresponsiveness (AHR), bronchoalveolar lavage (BAL), and blood collection were performed approximately 24 h after the last exposure. In both protocols, M, H, and HF GEE exposure significantly decreased BAL neutrophils from nonsensitized mice but had no significant effect on BAL cells from OVA-sensitized mice. In the pre-OVA protocol, GEE exposure increased OVA-specific IgG(1) but had no effect on BAL interleukin (IL)-2, IL-4, IL-13, or interferon (IFN)-gamma in OVA-sensitized mice. Nonsensitized GEE-exposed mice had increased OVA-specific IgG(2a), IgE, and IL-2, but decreased total IgE. In the post-OVA protocol, GEE exposure reduced BAL IL-4, IL-5, and IFN-gamma in nonsensitized mice but had no effect on sensitized mice. These results suggest acute exposure to the gas-vapor phase of GEE suppressed inflammatory cells and cytokines from nonsensitized mice but did not substantially exacerbate allergic responses.     

Effects of Gasoline Engine Emissions on Preexisting Allergic Airway Responses in Mice

Gasoline-powered vehicle emissions contribute significantly to ambient air pollution. We hypothesized that exposure to gasoline engine emissions (GEE) may exacerbate preexisting allergic airway responses. Male BALB/c mice were sensitized by injection with ovalbumin (OVA) and then received a 10-min aerosolized OVA challenge. Parallel groups were sham-sensitized with saline. Mice were exposed 6 h/day to air (control, C) or GEE containing particulate matter (PM) at low (L), medium (M), or high (H) concentrations, or to the H level with PM removed by filtration (high-filtered, HF). Immediately after GEE exposure mice received another 10-min aerosol OVA challenge (pre-OVA protocol). In a second (post-OVA) protocol, mice were similarly sensitized but only challenged to OVA before air or GEE exposure. Measurements of airway hyperresponsiveness (AHR), bronchoalveolar lavage (BAL), and blood collection were performed ～24 h after the last exposure. In both protocols, M, H, and HF GEE exposure significantly decreased BAL neutrophils from nonsensitized mice but had no significant effect on BAL cells from OVA-sensitized mice. In the pre-OVA protocol, GEE exposure increased OVA-specific IgG₁ but had no effect on BAL interleukin (IL)-2, IL-4, IL-13, or interferon (IFN)-γ in OVA-sensitized mice. Nonsensitized GEE-exposed mice had increased OVA-specific IgG_2a, IgE, and IL-2, but decreased total IgE. In the post-OVA protocol, GEE exposure reduced BAL IL-4, IL-5, and IFN-γ in nonsensitized mice but had no effect on sensitized mice. These results suggest acute exposure to the gas–vapor phase of GEE suppressed inflammatory cells and cytokines from nonsensitized mice but did not substantially exacerbate allergic responses.     

Surface-linked liposomal antigen induces IgE selective unresponsiveness in a T-cell independent fashion

We previously reported that surface-linked liposomal antigen induced IgE-selective unresponsiveness. The results were consistent even when different coupling procedures for antigen with liposomes, or for liposomes with different lipid components, were employed. During the course of an investigation intended to clarify the mechanism of IgE-selective unresponsiveness induced by surface-coupled liposomal antigens, we discovered an alternative approach to regulate the production of IgE, one that is independent of the activity of T-cells. Immunization of mice with OVA-liposome conjugates induced IgE- selective unresponsiveness without apparent Th1 polarization. Neither interleukin-12 (IL-12), IL-10, nor CD8(+) T-cells participated in the regulation. Further, CD4(+) T-cells of mice immunized with OVA-liposome were capable of inducing antigen-specific IgE synthesis in athymic nude mice immunized with alum-adsorbed OVA. On the other hand, immunization of the recipient mice with OVA-liposome did not induce anti-OVA IgE production, even when CD4(+) T-cells of mice immunized with alum-adsorbed OVA were transferred. In the secondary immune response, OVA-liposome enhanced anti-OVA IgG antibody production but not the ongoing IgE production, suggesting that the IgE-selective unresponsiveness induced by the liposomal antigen involved direct effects on IgE but not IgG switching in vivo. These results suggest the role of an alternative mechanism, one not involving T-cells, in the regulation of IgE synthesis, and raise the possibility that surface-linked liposomal antigen is potentially applicable for the development of a novel vaccine that induces the least IgE synthesis. Moreover, given the relatively low allergic response to and increased antigenicity of the allergen, this form of antigen preparation would be applicable to allergen immunotherapy.     

Pinocembrin attenuates allergic airway inflammation via inhibition of NF-κB pathway in mice

Pinocembrin, one of the primary flavonoids in propolis, possesses many biological activities, including anti-inflammation, anti-oxidation and immunoregulation. This study aimed to evaluate whether pinocembrin could attenuate ovalbumin (OVA)-induced allergic airway inflammation in mice and to explore the possible mechanism. BALB/c mice sensitized and challenged with OVA were administered intraperitoneally with pinocembrin. Airway inflammation and airway hyperresponsiveness were examined. T-helper type (Th) 2 cytokines in bronchoalveolar lavage fluid (BALF) and OVA-specific immunoglobulin E (IgE) in serum were determined. The activation of nuclear factor kappa B (NF-κB) p65 were also measured. Our results showed that pinocembrin resulted in significant inhibition of pathophysiological signs of allergic asthma, including increased pulmonary eosinophilia infiltration, mucus hypersecretion and airway hyperresponsiveness (AHR). Treatment with pinocembrin significantly reduced Th2 cytokines interleukin (IL)-4, IL-5 and IL-13 in BALF, and OVA-specific IgE in serum. Moreover, pinocembrin treatment suppressed phosphorylation of inhibitor-κBα (IκBα) and NF-κB subunit p65 activation in lung tissue of OVA-sensitized mice. These data suggest that pinocembrin may inhibit allergic airway inflammation, and providing potential benefits in the treatment of inflammatory disease.     

Covalent linkage of IL-12 and ovalbumin confines the effects of IL-12 to ovalbumin-specific immune responses

In order to direct the form of the immune response in an antigen-specific manner, we constructed a fusion protein (OVA/IL12) that contained the T cell-dependent antigen, ovalbumin (OVA), covalently linked to murine interleukin-12 (IL-12). The OVA/IL12 protein was produced in a baculovirus expression system and was purified by anti-OVA immunoaffinity chromatography. The purified OVA/IL12 protein displayed potent IL-12 bioactivity in an IL-12 proliferation assay. BALB/c mice immunized with the OVA/IL12 protein produced increased quantities of anti-OVA IgG2a antibody compared with mice immunized with recombinant OVA alone. Lymph node cells from the immunized mice with the OVA/IL12 protein produced large amounts of IFN-gamma when restimulatedin vitro with OVA, while those from mice immunized with the OVA protein produced little or no IFN-gamma. In contrast, immunization with a mixture of OVA and free recombinant IL-12 also induced IFN-gamma production, which was not OVA-specific. These studies indicate that the OVA/IL12 fusion protein can induce OVA-specific, Th1-dominated imnune responses, and that the covalent linkage of OVA and IL-12 confines the effect of IL-12 to OVA-specific cells.