矽肺大鼠肺脏对不同侵入途径、不同抗原的免疫应答

目的 通过观察矽肺大鼠肺脏对不同途径、不同抗原的免疫应答,探讨矽肺易受感染的免疫学机制。方法分别2次通过气道、腹腔途径给予矽肺大鼠模型及正常对照动物绵羊红细胞(SRBC)或卡介苗(BCG)进行免疫后,再观察皮内注射SRBC及BCG动物迟发性变态反应;实验终期检测血清和肺灌洗回收液特异性IgG水平及细胞因子浓度。结果SRBC免疫后矽肺气道免疫组表现出异常强烈的迟发性变态反应,矽肺气道BCG免疫各组出现相同反应;两种抗原免疫后矽肺动物血清及肺灌洗液特异性IgG水平显著高于正常对照组;BCG免疫动物中,矽肺气道免疫组动物肺灌洗液IFN-γ水平显著高于矽肺腹腔免疫组及正常对照组,3个组的TNF-α水平差异无显著性;SRBC免疫动物3个组的IFN-γ水平差异无显著性。结论矽肺对肺局部以及机体免疫功能具有明显影响,导致对外来抗原产生异常强烈的体液免疫反应和迟发性变态反应;肺局部参与细胞免疫调节的细胞因子对不同抗原有不同反应。     

白介素—8水平与医院感染性肺炎关系的初步研究

目的 :探讨全身及局部白介素 - 8(IL - 8)水平与医院内感染性肺炎 (NosocomialPneumonia ,NP)发生的关系 ,为NP发病免疫机制的研究提供实验依据。方法 :以气管切开 (或插管 )病人为研究对象 ,按全国医院感染监控中心制订的标准确诊NP。用防污染标本刷 (PSB)采集下呼吸道分泌物 ,ELISA法测定下呼吸道分泌物及血清中IL - 8的水平。结果 :NP组较对照组血清IL - 8水平显著升高 ,第 5天分别为 ( 3.96± 2 .75) μg·L- 1和 ( 3.54± 1.82 ) μg·L- 1,第 7天分别为 ( 4 .4 6± 1.13) μg·L- 1和 ( 3.4 1± 1.56) μg·L- 1;下呼吸道分泌物中的IL - 8水平第 5天分别为( 4 .36± 2 .68) μg·L- 1和 ( 3.79± 1.89) μg·L- 1,第 7天分别为 ( 4 .99± 2 .0 1) μg·L- 1和 ( 3.58± 2 .2 3)μg·L- 1,且高于血清IL - 8水平。NP组在入院第 5～ 7天血清IL - 8呈上升趋势 ,与出现NP的时间相吻合。结论 :IL - 8可能是免疫炎症反应中重要的细胞因子 ,IL - 8水平升高可能是NP发生的早期标志 ,具有一定的诊断价值。     

金属研磨尘染毒大鼠支气管肺泡灌洗液的变化

目的　观察金属研磨的混合粉尘对大鼠呼吸系统的损伤作用。方法　大鼠经支气管注入磨工粉尘染尘后饲养 2周 ,采用大鼠支气管肺灌洗技术 ,分析灌洗液中细胞含量、分类、存活率及乳酸脱氢酶 (LDH)、碱性磷酸酶 (ALP)活力的变化。结果　染尘大鼠肺泡灌洗液中细胞含量随磨工粉尘染尘剂量的加大而增大 ,且均高于SiO2 尘组。大鼠支气管肺泡灌洗液中性粒细胞比例 [SiO2 粉尘组为 (33 .83± 4 .54) % ,1 0、2 5、50mg/ml磨工粉尘组分别为 (2 6 .50± 3 .99) %、(36 .0 0± 3 .58) %和 (38.0 0±2 .1 0 ) % ]均较对照组 [(2 .83± 0 .75) % ]明显增加 ;巨噬细胞比例 [SiO2 粉尘组为 (62 .1 7± 4 .54) % ,1 0、2 5、50mg/ml磨工粉尘组分别为 (70 .83± 3 .66) %、(60 .83± 2 .1 4 ) %和 (58.1 7± 2 .48) % ]比对照组[(95 .67± 1 .2 1 ) % ]相应降低 ,差异均有显著性 (P <0 .0 1 )。对照组大鼠肺泡灌洗液细胞存活率达80 %以上 ,与磨工粉尘组、TiO2 组的差异有显著性 (P <0 .0 1 )。各染尘组大鼠肺灌洗上清液中LDH、ALP活力明显增加 ,与对照组的差异有显著性 (P <0 .0 1或P <0 .0 5) ,随磨工粉尘染尘剂量加大 ,LDH、ALP活力逐渐升高。结论　磨工粉尘对大鼠肺细胞有损害作用 ,进一步证实磨工粉尘可能对肺脏有致纤     

染矽尘小鼠肺组织中转化生长因子β1表达的逆转录聚合酶链反应检测

目的　探讨染矽尘小鼠肺组织转化生长因子 β1(TGF β1)基因的表达在矽肺发病中的意义。方法　采用暴露式气管内注入法给小鼠一次性染矽尘 (0 .2g/kg体重 ) ,染尘后第 1、3、5、7、14、2 8天 ,每组各处死 8只小鼠 ,取肺组织 ,用逆转录聚合酶链式反应 (RT PCR)方法测定小鼠肺组织TGF β1基因的表达。结果　染尘后第 3天 ,小鼠肺组织中TGF β1基因表达开始升高 (1.2 0± 0 .15 ) ;第 7天达高峰 (1.74± 0 .19) ,与对照组 (1.0 1± 0 .16 )和染尘第 5天 (1.35± 0 .15 )比较 ,差异均有显著性 (P <0 .0 5 ) ;第 14天开始下降 ,但直到第 2 8天仍高于对照组。染矽尘小鼠肺组织羟脯氨酸含量随染毒后时间的延长 (1～ 2 8d)呈现持续上升的趋势。结论　TGF β1在矽肺早期的发生、发展过程中可能有重要作用。     

醋酸铅对大鼠脑细胞凋亡及bcl-2基因表达的影响

目的　探讨醋酸铅 (PbAc)对大鼠脑细胞凋亡的诱发作用及对bcl 2基因表达的影响。方法　SD大鼠腹腔分别注射PbAc 2 5、5 0、10 0mg/kg 5d ,第 6天用流式细胞仪分别测定其大脑皮层、海马和小脑组织的细胞凋亡率和bcl 2基因的表达产物Bcl 2蛋白含量。结果　染铅大鼠大脑皮层、海马、小脑细胞凋亡率 (% ) :2 5mg/kgPbAc组为 5 .80± 0 .87、4.82± 0 .37、4.82± 1.2 3 ,5 0 mg/kg组值高于 2 5mg/kg组 ,10 0mg/kg组值高于 5 0mg/kg组 ,均比对照组 (1.40± 0 .70、2 .0 0± 0 .6 3、1.6 6±0 .49)高 ,差异有显著性 (P <0 .0 1) ;并有剂量 -反应关系 (r值分别为 0 .998、0 .989、0 .997)。染铅大鼠大脑皮层、海马、小脑bcl 2基因表达 (FI指数 ) :2 5mg/kgPbAc组为 0 .6 8± 0 .0 3、0 .6 1± 0 .0 6、0 .6 9± 0 .0 5 ;5 0mg/kg、10 0mg/kg组值均与 2 5mg/kg组接近 ,但均比对照组 (1.0 0± 0 .13、1.0 0±0 .17、1.0 0± 0 .13)降低 ,差异有显著性 (P <0 .0 1) ;并有剂量 -反应关系 (r值分别为 0 .886、0 .787、0 .832 )。大鼠大脑皮层、海马和小脑细胞凋亡率与Bcl 2含量呈负相关 (r值分别为 - 0 .75 0、- 0 .5 0 9、- 0 .6 6 7)。结论　铅可以诱发大鼠脑细胞凋亡 ,其机制可能与脑组织内bcl 2基因表达下调有关     

苦瓜皂甙对老年荷瘤小鼠免疫功能的影响

目的 :探讨苦瓜皂甙对老年荷瘤小鼠免疫功能的调节作用。方法 :15月龄雌性昆明小鼠 ,随机分为老年对照组、实验对照组、实验 1组和实验 2组。均喂以普通饲料 ,其中两对照组饮用自来水 ,两个实验组饮用分别为 10 0mg·L- 1和 2 0 0mg·L- 1苦瓜皂甙水。饲养 5周后 ,对后三组动物腹腔均接种 0 .1ml浓度为 10 6 ·ml 1的S180肿瘤细胞 ,1周后处死动物取标本待测。结果 :两个使用苦瓜皂甙组小鼠胸腺和脾脏组织中CD8+T细胞数有增高趋势 ,胸腺中CD4 +CD8+双阳性T细胞数显著降低〔老年对照组 :(6 8.0 9± 5 .2 6 ) % ,实验对照组 :(5 8.82± 6 .5 2 ) % ,实验 1组 :(5 0 .5 8± 3.74 ) % ,实验 2组 :(45 .85± 5 .75 ) %〕 ;血清IL - 2水平回升明显 ,血清TNFα含量显著增高 ;老年对照组、实验对照组、实验 1组和实验 2组 ,血清IL - 2分别为 (2 8.5 7± 4 .90 )、(17.14± 3.2 7)、(2 2 .86± 3.2 7)、(2 7.76± 4 .2 0 )ng·L- 1,血清TNFα分别为 (185 .5 3± 35 .34)、(2 4 5 .83±2 7.39)、(2 92 .2 1± 2 4 .74 )、(2 89.12± 2 5 .18)ng·L- 1。但是两个使用苦瓜皂甙组之间 ,所有指标均没有统计学差异。结论 :苦瓜皂甙可改善老年荷瘤小鼠免疫功能 ,增强机体抗肿瘤能力     

矽肺大鼠肺脏对卡介苗、鸡红细胞抗原的免疫应答研究

目的：通过观察矽肺大鼠肺脏对抗原的免疫应答以及肺泡巨噬细胞吞噬功能,探讨矽肺易受感染的免疫学基础。方法：分别两次通过气道、腹腔给予矽肺大鼠模型及正常对照动物卡介苗（BCG）,动态检测两次免疫后血清特异性IgG水平,试验终末测定肺灌洗液特异性IgG水平;皮内注射BCG观察动物迟型超敏反应;气道注入鸡红细胞,评价肺泡巨噬细胞的吞噬功能;体外检测脾淋巴细胞分泌特异性IgG水平。结果：抗原免疫后矽肺气道/腹腔免疫组血清与肺灌洗液特异性IgG水平显著高于正常对照组,肺泡巨噬细胞吞噬率、吞噬指数显著低于正常对照大鼠,迟发性变态反应与正常对照相似。结论：矽肺大鼠对抗原刺激表现出强烈的特异性IgG反应,矽肺动物肺泡巨噬细胞吞噬功能显著下降。     

镉对小鼠子代体液免疫的影响及其与锌的关系

为了探讨锌对镉所致的子代免疫毒性的拮抗作用 ,我们进行了下列研究。1 材料与方法 :选用中山医科大学动物中心提供的昆明小鼠 ,雌雄 2∶1同笼 ,次晨检查发现阴栓者确定为受孕 ,共获孕鼠 6 1只 ,随机分为 6组。以氯化镉和硫酸锌灌胃 ,剂量和时间见表 1。实验期间每 3ｄ称重 1次 ,按体重调整灌胃表 1　孕鼠灌胃时间和药物剂量及仔鼠血清溶菌酶含量和溶血素滴度 (ｎ =10 )组别孕鼠受孕第 5天受孕第6～ 15天仔鼠溶菌酶(ｍｇ/Ｌ , ｘ±ｓ)溶血素滴度( ｘＧ±ｓ)1对照组双蒸水双蒸水 12 2± 2 2 10 2 0± 0 6 32补锌组　10 0ｍｇ锌 /ｋｇ双蒸水…     

睡眠剥夺对大鼠脑组织SOD的影响

目的 :观察睡眠剥夺后大鼠脑组织SOD含量的影响 ,探讨睡眠剥夺引起的脑损害机制及干预药物的作用。方法 :采用小平台水环境法 (FlowerPot)制作大鼠睡眠剥夺模型 ,以黄嘌呤氧化酶法测定睡眠剥夺后大鼠额叶、海马、脑干和下丘脑SOD含量变化 ,并观察黄芪干预对SOD活性的影响。结果 :睡眠剥夺 3d后大鼠脑额叶、海马、中脑和下丘脑的SOD活性分别为 (44 .3±5 .9)、(47.5± 7.8)、(5 7.8± 6 .0 )、(6 4.5± 6 .8)、NU·mgpro 1高于正常对照组的 (16 .7± 5 .8)、(11.3± 2 .8)、(2 0 .3± 3.8)和 (17.0± 5 .7)NU·mgpro 1(P <0 .0 1)。经黄芪干预后额叶、海马、中脑及下丘脑SOD活性分别降为 (31.3± 5 .7)、(2 7.3± 5 .8)、(32 .8± 6 .9)、(31.7± 7.8)NU·mgpro 1,低于生理盐水对照的 (46 .9± 5 .8)、(5 1.3± 10 .4 )、(5 9.4± 7.6 )和 (5 9.6± 8.3)NU·mgpro 1(P <0 .0 1)。结论 :睡眠剥夺过程可能存在自由基损害影响 ,黄芪有一定的抗氧化应激作用     

晕船大鼠体内铁含量的变化

目的　探讨模拟晕船条件下大鼠机体组织铁含量和尿铁排出的变化。方法　将SD大鼠随机分为晕船组和对照组 ,原子吸收分光光度法检测大鼠血清、尿液和部分器官中铁元素的含量。结果　血清、肝脏、大脑、小脑、肾上腺铁含量在对照组依次为 (46 9± 3 5) μmol/L、(94 9± 8 5) μg/g、(3 8 5± 7 5) μg/g、(86 9± 9 5) μg/g、(159 9± 2 1 6) μg/g ,在晕船组依次为 (2 8 1± 4 8) μmol/L、(47 9± 9 1) μg/g、(2 3 6± 6 1) μg/g、(53 0± 8 7) μg/g、(2 96 2± 2 6 5) μg/g ,两组比较 ,差异均具有统计学意义 ;与对照组相比 ,尿液铁在旋转第一天时 ,晕船组大鼠排出量显著减少 ,为 (40 1 4± 2 6 7) μg/d ,第二、三天时显著性增多 ,分别为 (750 7± 2 4 1) μg/d ,(764 3± 2 7 9) μg/d ;而心脏、脑干、下丘脑铁含量与对照组相比有升高的趋势 ,但差异无统计学意义。结论　晕船可能影响大鼠机体铁元素的分布 ,这种变化在晕船发生中的作用值得进一步探索。     

Effect of lung damage by acute exposure to nitrogen dioxide on lung immunity in the rat

Exposure to nitrogen dioxide (NO₂) damages Type I alveolar epithelial cells and the epithelium of the terminal bronchiole. Because an intact epithelium may help control the number of inhaled particles that are cleared by the pulmonary lymphatics, damage to the alveolar epithelium could alter the antigen load to the lung-associated lymph nodes (LALN). To determine the effects of lung damage by NO₂ inhalation on lung immunity, we exposed adult, male rats to 26 ppm NO₂ for 24 hr at various time intervals before and after intratracheal immunization with 10⁸ sheep red blood cells (SRBC). Seven days after immunization, we determined the number of anti-SRBC antibody-forming cells (AFC) in the LALN, cervical lymph nodes, and spleen. The immunologic response to SRBC was limited to the LALN, with few or no AFC in either the cervical lymph nodes or spleen. A fivefold increase in the number of IgG anti-SRBC $\text{AFC}\text{10}{}^6$ LALN cells was evident in rats immunized 1 day after NO₂ exposure. The increase was followed by a slight suppression of the IgG response when rats were immunized 3 days after exposure, returning to normal levels by 7 days after exposure. Histopathological examination of lung tissues showed a slight respiratory bronchiolitis which was followed by a bronchiolar epithelial cell hyperplasia and Type II cell hyperplasia in the adjacent alveoli. Based on these observations, it appears that the fluctuations observed in the LALN response may be the result of damage and subsequent repair of bronchiolar and alveolar epithelium following NO₂ inhalation.     

Effects on rat lung immunity by acute lung exposure to benzo(a)pyrene

This study describes the effect of intratracheal instillation of benzo(a)pyrene (BaP) on immunological responses in the lung-associated lymph nodes, cervical lymph nodes, and spleen after deposition of 10(8) sheep red blood cells (SRBC) in the lung or peritoneal cavity of rats. An increased number of anti-SRBC antibody-forming cells was observed in the lung-associated lymph nodes when rats were immunized simultaneously with BaP installation. A suppression in the number of anti-SRBC antibody-forming cells occurred when SRBC were given intratracheally 4 or 7 days after BaP. The effects of the BaP appeared to be on the function of the cells in the lung-associated lymph nodes rather than due to changes in the exposed lung. BaP-induced changes in antigen handling or in regulatory populations of immune cells in the lung-associated lymph nodes may be responsible for the immune alterations observed.     

二甲基苯蒽对金属硫蛋白基因敲除小鼠免疫功能的影响

目的：观察二甲基苯蒽（DMBA）对金属硫蛋白（MT）基因敲除小鼠[MT（－／－）]的免疫毒性。方法：选用MT（－／－）小鼠和MT（＋／＋]野生型小鼠进行对照,DMBA25mg/kg和50mg/kg分别1次腹腔注射染毒后,检测动物对静脉注射绵羊红细胞（SRBC）诱导的体液和细胞免疫反应,体液免疫指标为脾脏抗体形成细胞（PFC）数量变化,细胞免疫功能指标选择迟发型变态反应,即动物足跖肿胀厚度变化。结果：DMBA25mg/kg组,MT（－／－）小鼠脾脏和胸腺重量都减轻,体液免疫功能受到抑制（抑制率为72％）,而MT（＋／＋）小鼠仅脾脏重量减轻,两种小鼠的细胞免疫功能均未见明显变化,DMBA50 mg/kg组,MT（－／－）小鼠的体液免疫和细胞免疫功能受到抑制程度均比DMBA25mg/kg组严重（抑制率分别为91％和72％）。MT（＋／＋）小鼠虽脾脏和胸腺重量减轻,体液免疫受到抑制,但变化程度明显小于MT小鼠（－／－）。MT（＋／＋）小鼠没有出现明显的细胞免疫功能抑制。结论：MT（－／－）小鼠的体液免疫和细胞免疫功能更易被DMBA抑制。提示MT具有保护DMBA所致免疫伤的功能。     

Adequate immune response to tetanus toxoid and failure of vitamin A and E supplementation to enhance antibody response in healthy children

The effects of vitamin A and vitamin E supplementation on the IgG response to tetanus toxoid after primary immunization were evaluated in a prospective, randomized controlled clinical trial involving 89 healthy infants with normal serum vitamin A and E levels at 2 months of age. Before the first dose of DPT vaccine, the infants were randomly enrolled into four different study groups [Group I (n=24): 30,000 IU vitamin A for 3 days just after each three doses of primary vaccination, Group II (n=21): 150 mg oral vitamin E for only 1 day after the injections for primary immunization, Group III (n=21): vitamins A and E together in the same order, Group IV (n=23) no vitamin after DPT vaccines]. Serum tetanus antitoxin (IgG) titres were measured three times; initially at 2 months of age before the first dose of DPT, secondly at 5 months of age 1 month after primary immunization and thirdly at 16-18 months of age before the booster dose of DPT. Before the first dose of the DPT vaccine, 1 month after the third DPT injection and at 16-18 months before the booster dose of DPT, there was no significant difference in serum tetanus antitoxin levels between these four groups. A significant increase was observed in all the groups when serum tetanus antitoxin levels before (2 months) and after (5 months) primary immunization were compared. In addition, serum antibody levels against tetanus significantly decreased in the four groups before booster vaccination. Before the beginning of primary immunization, 15 infants (16.8%) had serum tetanus antitoxins (IgG) below protective level. After three doses of DPT, all the infants had protective antitoxin levels. At 16-18 months of age before booster dose, four infants (10%) also had serum tetanus antitoxins (IgG) below the protective level. No side-effects were observed except bulging fontanelle in two infants in Group I.     

Interference in the development of a secondary immune response in mice by zinc deprivation: persistence of effects

The purpose of this study was to determine the effects of a moderate period of zinc deficiency on the secondary responses of mice primed with antigen prior to nutritional insufficiency. Adult A/J mice were primed with sheep red blood cells (SRBC) 2 weeks prior to being placed on zinc-deficient, zinc-adequate or intake-restricted diets. After 28 days some of the mice in each treatment group were given a second injection of SRBC. Deficient mice could produce only 43% as many IgG anti-SRBC plaque-forming cells (PFC) per spleen as could the zinc-adequate or restricted-fed mice. To compare the secondary response of cells from each dietary group in a uniform environment, additional mice were killed as a source of primed splenocyte for transfer to irradiated hosts. Compared to controls, splenocytes from deficient mice gave suboptimal secondary responses even in normal irradiated hosts. Finally, the remaining mice were provided with zinc-adequate diet for a period of 4 weeks to allow for repair of the memory response, but it was only partially restored by this means. The data suggest that zinc deficiency may have destroyed a substantial portion of SRBC memory cells.     

Effect of honey on antibody production against thymus-dependent and thymus-independent antigens in primary and secondary immune responses

The objective was to study the effect of natural pure honey on the antibody production against thymus-dependent antigen [sheep red blood cells (SRBCs)] and thymus-independent antigen (Escherichia coli) in mice. Forty-two mice (mean weight 28.33 +/- 3.44 g) were divided into two groups: group A (21 mice) fed regular diet and group B (21 mice) fed regular diet plus 0.8 g/kg of body weight/day of honey administered in four equally divided doses. Each animal was injected intraperitoneally with 0.1 mL of 5% SRBCs and 0.1 mL of killed E. coli. The same dose of both antigens was given after 17 days. At days 7 and 16 after primary immunization and at day 4 after secondary immunization, blood samples were collected from seven mice at each time interval from group A and group B to estimate antibody titer using the hemoaggulination test. At day 7 after primary immunization, the mean antibody titer against SRBCs was 9.14 +/- 3.02 in group A and 13.7 +/- 3.9 in group B (P < .05), while the mean antibody titer against E. coli was 14.8 +/- 8.5 in group A and 14.8 +/- 9.35 in group B. At day 16, the mean antibody titer against SRBCs was 13.71 +/- 3.9 in group A and 20 +/- 9.8 in group B, while the mean antibody titer against E. coli was 14.69 +/- 935 in group A and 26.67 +/- 8.26 in group B (P < .05). Four days after secondary immunization, the mean antibody titer against SRBCs was 13.33 +/- 4.62 in group A and 16 +/- 8.7 in group B, while the mean antibody titer against E. coli was 42.67 +/- 18.4 in group A and 69.33 +/- 31.4 in group B. It might be concluded that oral honey stimulates antibody production during primary and secondary immune responses against thymus-dependent and thymus-independent antigens.     

Effects of inhaled hexachlorobenzene aerosols on rat pulmonary host defenses

Pulmonary bactericidal activity, macrophage phagocytic activity, alveolar macrophage (AM) enzyme activity, and T- and B-cell mitogenesis of lymphocytes from lung associated lymph nodes (LALN) or mesenteric lymph nodes (MESLN) were assessed in Sprague-Dawley rats exposed 4 hr/d, 4 days/wk for 1, 4, or 16 days to hexachlorobenzene (HCB) aerosols. Pulmonary bactericidal activity was depressed after 1 or 4 but not 16 exposures to 35 mg/m3 of HCB. AM phagocytosis of 51Cr-RBC in vitro was increased after 4 but not 1 or 16 exposures to HCB, and no effect was observed in peritoneal macrophages. HCB significantly enhanced mitogenesis in MESLN to the B-cell mitogen Salmonella typhimurium lipopolysaccharide (STM) after 4 exposures; LALN STM mitogenesis and LALN and MESLN mitogenesis to phytohemagglutinin (PHA) were not affected. After 16 exposures, however, the PHA responses in LALN and MESLN were significantly increased and decreased, respectively.     

Flow cytometric analysis of lymphocyte subpopulations in the spleen and thymus of mice exposed to an acute immunosuppressive dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

The objective of the present studies was to determine if acute exposure to an immunotoxic dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) produces alterations in the expression of lymphocyte surface markers as measured by multiparameter flow cytometry. The immunotoxicity of a single oral dose of TCDD was assessed by the anti-SRBC PFC response; an ED50 of 0.74 micrograms/kg was determined. Subpopulations in the spleen and thymus of C57B1/6 mice were analyzed 2 days following exposure to 2 micrograms/kg TCDD. In addition, splenic lymphocyte subsets were examined on Days 1-4 following SRBC challenge of mice treated with 0, 2, or 5 micrograms/kg TCDD. T and B cells were identified by single parameter analysis of Thy 1.2 and Ig expression. T cell subsets were defined by dual parameter analysis of CD4 and CD8 expression. In TCDD-treated mice, the percentage and the total number of double-positive CD4+ CD8+ thymocytes were significantly decreased while the percentage but not the total number of double-negative CD4- CD8- thymocytes was significantly increased. No changes in the percentage or total number of single positive (CD4+ CD8- or CD4- CD8+) thymocyte subsets were observed. In contrast to the thymus, lymphocyte subsets in the spleen were not significantly altered in percentage or total number 2 days following acute TCDD exposure. When splenic lymphocytes were analyzed daily following SRBC challenge, Ig+, Thy 1.2+, and CD4+ CD8- subpopulations remained relatively unchanged in both control and TCDD-treated animals. A small but significant decrease in the percentage of CD4- CD8+ T cells was observed on Day 3 in mice treated with 2 or 5 micrograms/kg TCDD when compared to that of vehicle-treated mice. The total number of CD4- CD8+ splenocytes was also significantly lower in the 5-micrograms/kg group on Day 3. However, this effect appeared to result from an elevation of the CD4- CD8+ subset in the controls rather than from a reduction in the TCDD-treated groups. Double-positive (CD4+ CD8+) lymphocytes were not detected in either control or TCDD-treated spleens. These results indicate that an acute dose of TCDD which reduced the splenic anti-SRBC response by 65-80% did not cause detectable changes in major splenic lymphocyte subpopulations. This is an important finding from the standpoint of utilizing lymphocyte subset analysis to screen for potential immunotoxic effects of TCDD. Specifically, the absence of subset changes does not preclude the presence of functional immunosuppression.     

Impairment of humoral immune responses in mice exposed to nitrogen dioxide and ozone mixtures

The relationship between immune defense mechanisms and environmental pollutants remains unknown because of uncertainty about the effects of combined or mixed pollutants. To investigate whether exposure to toxic gas mixtures change the effect of a single gas exposure on immune function, BALB/c mice were continuously exposed to 4.0 ppm nitrogen dioxide (NO2), 0.8 ppm ozone (O3), or the mixture of NO2 plus O3 for 3, 7, 14, and 56 days. Organ weights (lung, thymus, and spleen) and antibody responses to sheep red blood cells (SRBC), and to DNP-Ficoll were measured immediately after the exposure. Lung weights in mice exposed to O3 or the mixture were increased significantly in all exposure periods. The weights of thymus and spleen in mice exposed for 3, 7, and 14 days to the mixture were decreased. O3 exposure for 56 days showed significant decreases of the weights of both organs. Antibody response to SRBC in mice exposed for 3, 7, and 14 days to O3 or the mixture was markedly suppressed, but exposure to the mixture for 56 days did not show the suppression of anti-SRBC antibody response. No differences in anti-DNP antibody response between exposed and control mice were observed, except those exposed to O3 or the mixture for 14 days. These results suggest that mixed gas exposures variously modify the effects of a single gas exposure on antibody production in mice.     

油菜蜂花粉及其丙酮提取物对免疫增强作用的研究

本文观察了油菜蜂花粉及其丙酮提取物对正常和由于免疫抑制剂环磷酰胺、荷瘤及抗淋巴细胞血清所致免疫低下小鼠的免疫增强作用。结果表明,蜂花粉及其丙酮提取物对正常幼年和成年小鼠能提高血清抗SRBC抗体的含量(HC_(50))和增加脾脏空斑形成细胞(PFC)。蜂花粉丙酮提取物对环磷酰胺、荷瘤及抗淋巴细胞血清等所致免疫低下小鼠的血清抗SRBC抗体、定量脾细胞体外分泌抗SRBC抗体(QHS)、脾脏空斑形成细胞(PFC)和特异玫瑰花形成细胞(SRFC)减少均有明显对抗作用。上述结果提示,油菜蜂花粉及其丙酮提取物有免疫增强作用,丙酮提取物可能是该花粉所含一种增强兔疫作用的活性物质。