弓形虫昆山分离株P30蛋白的纯化、复性和鉴定

目的表达并纯化弓形虫昆山分离株膜蛋白P30。方法将构建的pET28b-P30重组质粒转入大肠埃希菌BL21,挑重组菌于LB培养基中增菌,IPTG诱导其表达,然后纯化包涵体,用尿素溶解包涵体,Ni2 螯合柱纯化产物,以透析法复性蛋白,并用SDS-PAGE和Western blot进行鉴定。结果大肠埃希菌表达的P30蛋白以包涵体的形式存在,P30蛋白经Ni2 螯合柱纯化后纯度大于95%。经Western blot鉴定,复性蛋白能被弓形虫感染的鼠血清识别。结论得到了纯度高的膜蛋白P30。     

弓形虫P30基因重组质粒的构建及其免疫效果

目的　通过构建含弓形虫P30不同表达形式 (膜型、分泌型及细胞内型 )的重组质粒 ,并将其用于免疫小鼠 ,测定抗体水平 ,以期初步筛选出一种对弓形虫感染具有良好保护作用的核酸疫苗。　方法　利用PCR技术和亚克隆技术分别构建弓形虫表膜型P30基因重组质粒 (含完整的P30编码序列 ,包括信号肽及疏水尾 )pcDNA3 P30Mb ,分泌型P30基因重组质粒 (含完整的P30编码序列 ,不包括疏水尾 )pcDNA3 P30Se以及细胞内型P30基因重组质粒 (含完整的P30编码序列 ,但不包括信号肽 )pcDNA3 P30In。将以上 3种重组质粒分别与脂质体混合后免疫小鼠 ,ELISA及免疫印迹测定小鼠血清中特异的IgG抗体。　结果　成功构建了弓形虫P30基因 3种表达形式的重组质粒 ,经双酶切鉴定及DNA序列测定 ,3种重组质粒中的插入片段确为P30的编码基因 ,且读码框架正确 ;抗体测定显示 :3个免疫组均能诱导小鼠产生特异的IgG抗体 ,但各组之间IgG出现的时间及强度有一定的差异。　结论　用编码弓形虫P30抗原的重组质粒进行核酸免疫 ,能诱导免疫小鼠产生特异性的IgG抗体 ;膜型及分泌型免疫小鼠的特异IgG抗体出现的时间早于细胞内型免疫鼠 ,但 4wk后 3组间差异无显著性。     

含弓形虫P30基因插入昆虫杆状病毒的研究

目的：将弓形虫ＺＳ１株主要表膜抗原（Ｐ３０）基因插入到昆虫杆状病毒基因组中，为在昆虫细胞或昆虫体内表达及生产Ｐ３０作准备。方法：先将Ｐ３０基因亚克隆到转移载体质粒ｐＳＸ－ＩＶＶＩ＋Ｘ３中，然后用此重组载体质粒ＤＮＡ与亲本株病毒ＤＮＡ共转染培养的草地夜蛾细胞，经空斑纯化筛选出重组病毒株。结果：已得到含Ｐ３０基因的重组杆状病毒ＴｎＮＰＶ－Ｐ３０。结论：本文已将弓形虫ＺＳ１株Ｐ３０基因亚克隆到昆虫杆状病毒ＴｎＮＰＶ中。     

弓形虫GRA4和SAG2基因重组BCG疫苗免疫保护性的比较研究

目的 比较弓形虫致密颗粒蛋白4（GRA4）基因和表面抗原2（SAG2）基因的重组卡介苗（BCG）对小鼠的免疫保护效果。 方法 108只SPF级雌性BALB/c小鼠随机分成6组：PBS组、BCG空白菌组、BCG?鄄空白载体组、BCG?鄄SAG2组、BCG-GRA4组和BCG-SAG2+GRA4组,每组18只。每鼠分别注射对应液体/疫苗100 μl,共2次,间隔2周。接种前尾静脉采血,接种后4、6、8周每组分别剖杀3只,取脾和眼眶血检测细胞因子、IgG与IgM抗体,T淋巴细胞亚群计数,淋巴细胞转化率等。末次免疫后3周,每组剩余小鼠分别腹腔接种RH株弓形虫速殖子50个进行攻击感染,观察各组小鼠存活时间。 结果 弓形虫SAG2和GRA4重组BCG疫苗均能诱导小鼠产生免疫应答。第4周时,BCG-GRA4+SAG2免疫组小鼠的CD3⁺CD4⁺/CD3⁺CD8⁺ 的比值最高,为14.06%±1.17%。第6周时,BCG-GRA4+SAG2免疫组小鼠的IgG抗体水平最高, 为0.18±0.02。第8周时,BCG-SAG2免疫组小鼠的IgM抗体水平最高,为0.82±0.05;弓形虫速殖子攻击后,BCG-SAG2组平均存活8.61 d,PBS对照组平均存活7.33 d,3个免疫组小鼠比其他3组的平均存活时间长1 d。 结论 弓形虫重组BCG疫苗具有一定的免疫保护性。     

小鼠口服弓形虫DNA混合疫苗的免疫保护反应

目的 观察携带弓形虫表面抗原复合基因重组沙门氏菌经口免疫BALB/c小鼠所诱导的免疫反应。 方法 构建弓形虫主要表面抗原SAG1、SAG2复合基因真核表达质粒，将其转入减毒鼠伤寒沙门氏菌BRD509 (BRD509/pSAG1/SAG2)，经口服免疫BALB/c小鼠，以携带空载体质粒的减毒沙门氏菌BRD509及生理盐水（NS）组为对照，分别于每次免疫前和免疫后断尾取血，并于末次免疫后第4周取小鼠脾脏测定T淋巴细胞增殖活性、天然杀伤细胞（NK细胞）活性和T细胞亚群；ELISA法测定IgG抗体及血清中的细胞因子干扰素（IFN-γ），白介素-4（IL-4）。与末次免疫后4周，每只小鼠腹腔注射0.1 ml(10⁵)弓形虫RH株速殖子攻击，观察小鼠存活时间。 结果 免疫组小鼠的IgG抗体水平明显提高，滴度为1∶100；NK细胞杀伤活性和T细胞增殖活性也明显增强，其中NK细胞杀伤活性为85%±7%，T细胞增殖指数为2.83，与对照组相比差异有统计学意义(P < 0.05)。免疫鼠攻击感染后平均存活时间比对照组长5 d。 结论 弓形虫口服DNA混合疫苗可诱导小鼠产生保护性免疫。     

弓形虫多基因核酸疫苗构建及其免疫保护性研究

目的 构建弓形虫多基因核酸疫苗, 评价其免疫保护性。方法 PCR扩增热休克蛋白 （HSP70） 基因片段, 克隆到 pcDNA3?ROP2?p30重组质粒中, 构建pcDNA3?ROP2?p30?HSP70多基因核酸疫苗。采用该疫苗免疫BALB/c小鼠, 检测小鼠脾淋巴细胞及全血CD4+ 、 CD8+ , 血清、 脾淋巴细胞培养液中IgG、 IgM、 IgA和IFN?γ、 TNF、 IL?2、 IL?4、 IL?12等, 并进行弓形虫攻击感染实验。结果 应用PCR扩增出916 bp HSP70基因片段, 成功构建pcDNA3?ROP2?p30?HSP70重组体, 其中包含 HSP70 蛋白基因读码框内的完整序列。该弓形虫多基因核酸疫苗能诱发小鼠产生细胞免疫和体液免疫, 实验组小鼠血清抗体滴度高, CD4+ 和 CD8+ 均增殖明显, 组间差异有统计学意义（FCD4+ =45.00, FCD8+ =15.01, P均＜0.01）; 其血清及脾细胞培养液中IFN?γ、 IL?2和IL?12含量均明显升高, 尤以血清中升高显著。攻击实验结果显示, 实验组小鼠存活时间明显延长。结论 pcDNA3?ROP2?p30?HSP70多基因核酸疫苗具有较强的免疫原性, 能产生较好的免疫保护作用。     

弓形虫表面抗原P30基因分枝杆菌-大肠杆菌穿梭表达重组质粒的构建及序列测定

目的　构建编码弓形虫RH株表面抗原P30基因的分枝杆菌 -大肠杆菌穿梭表达重组质粒并进行其序列测定。方法　弓形虫RH株腹腔接种小鼠 ,收集腹水 ,酚 /氯仿法抽提基因组DNA ;根据基因库P30基因序列设计合成一对引物 ,采用PCR法扩增编码P30的基因片段 ,经低熔点琼脂糖法回收并纯化 ;将P30基因定向克隆到分枝杆菌 -大肠杆菌穿梭表达质粒 ,转化大肠杆菌DH5dα,在卡那霉素阳性LB培养基平板筛选阳性重组子 ,并经双酶切及PCR鉴定 ;最后对重组子进行序列测定。结果　PCR所扩增的P30基因片段为 10 37bp ,阳性重组质粒pBCG -P30经XbaI+KpnI双酶切 ,获得包含P30和热休克蛋白 (hsp70 )启动子的复合基因片段 ,此片段的大小为 1170bp ,与预期的理论值相符合。序列测定分析进一步表明所克隆的基因为编码P30抗原的基因片段。结论　成功构建编码弓形虫表面抗原P30基因大肠杆菌 -分枝杆菌穿梭质粒pBCG -P30。     

弓形虫P30乳酸球菌口服疫苗诱导小鼠的体液免疫反应及保护性观察

目的观察弓形虫P30乳酸球菌口服疫苗在小鼠体内诱导的体液免疫反应,以及产生的保护性效果. 方法P30乳酸球菌口服免疫BALB/c小鼠,以gp42乳酸球菌组和生理盐水组为对照,4周内免疫7次,免疫结束后,分别收集各组小鼠血清,ELISA法检测血清中总抗体IgG和抗体亚类IgG1和IgG2a水平,同时用100个弓形虫RH株速殖子攻击各实验小鼠. 结果 P30乳酸球菌口服免疫小鼠组检测到了相应的抗体,抗体亚类IgG2a的生成量稍高于IgG1,两对照组均检测不到明显的相应抗体;攻击后,口服疫苗免疫组平均存活时间多于对照组4 d. 结论 P30乳酸球菌口服疫苗刺激小鼠产生了相应的抗体,诱导产生了偏向Th1型的免疫反应,且在小鼠体内发挥了部分保护作用.     

弓形虫P30乳酸球菌口服疫苗诱导小鼠的细胞免疫反应及抗体生成的动态过程

目的　观察弓形虫P30乳酸球菌口服疫苗诱导小鼠产生的细胞免疫效果和抗体IgG的动态发生过程。方法　口服免疫BALB/c小鼠 ,一个月后 ,取鼠脾细胞作ConA刺激淋转试验 (MTT法 )及T细胞亚群的测定 ;不同免疫时间段内 ,收集实验鼠血清 ,ELISA法检测抗体水平的变化。结果　P30乳酸球菌口服免疫组脾淋巴细胞ConA刺激后增殖能力比两对照组显著提高 ,CD+ 4 和CD+ 8的百分数均明显升高 ;第 12周 (即最后一次免疫结束一个月 ) ,P30乳酸球菌口服免疫组检测到特异性抗体IgG。结论　P30乳酸球菌口服疫苗有效地激发了小鼠细胞免疫反应 ,特异性抗体IgG在免疫结束一个月后生成明显。     

弓形虫ROP2-P30重组真核表达质粒的构建及其免疫效应的初步分析

目的构建弓形虫棒状体蛋白2（ROP2）和膜表面蛋白1（P30）融合的重组真核表达质粒,观察融合抗原ROP2-P30以DNA免疫方式在体内的免疫学效应。方法以重组质粒pET28b/ROP2-P30为模板,利用分子克隆技术构建重组真核表达质粒pcDNA3.1/ROP2-P30,经PCR和酶切鉴定正确后,体外转染COS-7细胞,Westernblot检测ROP2-P30表达。重组质粒pcDNA3.1/ROP2-P30以每鼠100μg混合透明质酸酶10U的剂量肌肉注射免疫BALB/c雌性小鼠,以弓形虫虫体裂解抗原作包被抗原,ELISA法测定免疫小鼠血清IgG抗体,免疫结束2周后,以约100个弓形虫速殖子攻击感染小鼠,观察小鼠生存状况。结果PCR和酶切鉴定表明重组质粒pcDNA3.1/ROP2-P30构建正确;Westernblot显示该重组质粒在COS-7细胞中瞬时表达的产物可被重组ROP2-P30免疫兔血清识别;ELISA检测重组质粒免疫小鼠血清特异性IgG抗体水平升高;重组质粒免疫小鼠感染弓形虫后的存活时间较对照组有所延长。结论重组真核表达质粒pcDNA3.1/ROP2-P30构建成功,用该重组质粒DNA直接免疫小鼠,能够诱导产生特异的体液免疫反应,具有一定的免疫保护性;该重组质粒表达的融合抗原分子ROP2-P30具有免疫原性,可作为疫苗候选抗原深入研究。     

弓形虫表面抗原P30 DNA疫苗免疫小鼠诱导体液免疫应答及保护性的初步观察

目的观察弓形虫表面抗原P30 DNA疫苗免疫BALB/c小鼠诱导其体内产生的体液免疫应答及抗虫感染的免疫保护作用. 方法重组质粒pBK-P30用生理盐水稀释后,肌注免疫BALB/c小鼠.分别于免疫后5周和10周,ELISA测定IgG抗体滴度;取免疫鼠的血液、肺、心脏、肝脏、脾、肾脏及肌肉PCR扩增P30基因;免疫鼠腹腔注射弓形虫速殖子攻击感染.结果两次检测,均可测到特异性IgG抗体,且抗体的滴度随免疫时间的延长而增高;免疫后5周,免疫鼠的上述组织均可扩增出P30基因条带,但免疫后10周仅血液扩增出特异P30基因条带;弓形虫速殖子腹腔攻击感染,免疫组鼠的平均存活时间较对照组鼠延长,但统计学差异不显著(P＞0.05). 结论弓形虫表面抗原P30 DNA疫苗能诱导BALB/c小鼠产生特异性体液免疫应答及部分抗虫免疫保护作用.     

表达弓形虫棒状体蛋白1的重组乳酸乳球菌诱导小鼠免疫应答的研究

目的用表达弓形虫棒状体蛋白1（ROP1）的乳酸乳球菌口服免疫小鼠,观察其所诱导的体液免疫、黏膜体液免疫和保护力。方法69只BALB/c小鼠随机分成疫苗免疫组、乳球菌对照组和生理盐水组,每次分别饲喂5×109个/鼠悬浮在缓冲液中的重组乳酸乳球菌、不含重组质粒的乳酸乳球菌及等体积的生理盐水。第27、34、48天分别从鼠尾静脉采血,分离血清,酶联免疫吸附试验（ELISA）检测IgG水平;第48天杀死3只小鼠,分离小肠黏液检测SIgA水平;第48天用弓形虫灌胃感染小鼠,观察小鼠发病情况,计算小鼠死亡率,30 d后统计小鼠肝、脑组织中的虫体数量。结果疫苗免疫组小鼠IgG水平与乳球菌对照组、生理盐水组比较,差异均有统计学意义（P均〈0.01）。疫苗免疫组小鼠SIgA水平与乳球菌对照组、生理盐水组比较,差异均有统计学意义（P均〈0.01）。疫苗免疫组小鼠肝、脑组织中虫体数与乳球菌对照组、生理盐水组比较,差异均无统计学意义（P均〉0.05）。结论表达弓形虫ROP1蛋白的乳酸乳球菌可诱导小鼠体液免疫和黏膜体液免疫,但对弓形虫感染无保护力。     

On the increase of portal pressure during the acute and chronic phases of murine schistosomiasis mansoni and its reversibility after treatment with oxamniquine

The purpose of the present study was to evaluate the effect of treatment with oxamniquine on the portal pressure of mice infected with Schistosoma mansoni. The animals were infected with 30 cercariae and portal pressure was measured with a polygraph at 70 (acute phase) and 160 (chronic phase) days after infection. On days 70 and 160 two other groups of infected mice were treated with 400 mg/kg of oxamniquine and portal pressure was measured 90 days later (160 and 250 days after infection). A group of uninfected mice was used as control. The measured portal pressures, in mmHg, were: matched uninfected control mice 8.7+/-2.1 and acute phase group, measured at day 70, 13.4+/-3.5. Matched uninfected control 7.5+/-0.6 and chronic phase group, measured at day 160 post-infection, 11.6+/-1.5. Matched uninfected mice 6.9+/-0.9 and chronic phase group, measured at day 250, 10.4+/-1.8. Oxamniquine-treated at day 70 and measured at day 160 7.9+/-0.4; oxamniquine-treated at day 160 and measured at day 250, 7.6+/-1.7. The infection of mice with 30 cercariae of S. mansoni induced portal hypertension, both during the acute and chronic phases and treatment with oxamniquine caused portal pressure to return to normal levels.     

抗P30 McAb对弓形虫感染的保护性作用

用杂交瘤技术获得抗弓形虫Ｐ３０ＭｃＡｂ,按不同剂量分别与同等数量的弓形虫ＲＨ株（２×１０５／ｍｌ）作用后,经腹腔注射ＢＡＬＢ／ｃ鼠,发现该ＭｃＡｂ对弓形虫感染具保护性作用。ＲＨ株致死量试验显示：每鼠注射１０个虫体,１ｗｋ内死亡率达６２．５％,９ｄ内全部死亡,而在３．００ｍｇ的ＭｃＡｂ保护下注射１０５ＲＨ株虫体的小鼠可在１０ｄ内无一死亡。用目测概率法计算其ＥＤ５０为每鼠１．２３ｍｇ／１０５ＲＨ株虫体。对照组与实验组小鼠存活时间及存活率间经统计学检验均有显著性差异。     

刚地弓形虫ROP2-P30复合重组蛋白疫苗对BALB／c小鼠免疫保护性的研究

目的用刚地弓形虫ROP2-P30复合重组蛋白疫苗免疫BALB/c小鼠观察对机体的影响,为研制安全有效的弓形虫疫苗奠定基础。方法PCR方法从刚地弓形虫基因组中扩增出ROP2和P30片段,将这两个片段分别亚克隆至pET-30a原核表达载体中,表达出ROP2-P30复合重组蛋白。用蛋白疫苗免疫BALB/c小鼠,ELISA检测免疫小鼠后体液中抗体和细胞因子的变化,观察攻击试验小鼠的的死亡率。结果ROP2-P30复合重组蛋白疫苗免疫BALB/c小鼠诱导机体产生大量的IgM、IgG抗体和IFN-γ、IL-2及IL-4细胞因子。攻击试验表明,复合重组蛋白免疫组和对照组相比,小鼠的存活时间明显延长。结论ROP2-P30复合重组蛋白免疫BALB/c小鼠诱导其产生高水平的体液和细胞免疫应答,该复合重组蛋白是抗刚地弓形虫感染的候选疫苗之一。     

Growth hormone accelerates immune recovery following allogeneic T-cell-depleted bone marrow transplantation in mice

OBJECTIVE: To test in a murine model whether recombinant human growth hormone can promote immune recovery after allogeneic T-cell-depleted bone marrow transplantation. MATERIALS AND METHODS: Lethally irradiated (8.5 Gy) BALB/c mice (H2(d)) were transplanted with 5 x 10(6) T cell-depleted bone marrow cells from C57BL/6 mice (H2(b)). Recipient mice were injected intraperitoneally with recombinant human growth hormone (20 microg/dose/day) or saline for the first 4 weeks after transplantation. These animals were followed for phenotypic and functional immune recovery. RESULTS: Administration of human recombinant growth hormone improved the CD4(+) T-cell counts in peripheral blood on day +14 (44+/-14 vs 33+/-7/microL blood, p<0.05) and day +21 (281+/-109 vs 187+/-76/microL blood, p<0.01) compared with the saline control. These differences were no longer significant by day +28 despite continued growth hormone administration. Similar effects were also observed on CD8(+) T cells and B220(+) B cells. The improvements in peripheral T-cell counts were at least partially as a result of enhanced thymopoiesis because there was an increase in total thymocytes after treatment with growth hormone. T-cell-depleted bone marrow recipients treated with growth hormone rejected the third-party grafts faster than those treated with saline control (median survival time: 20 days vs 26 days, p<0.05). CONCLUSIONS: These data demonstrated that recombinant human growth hormone can accelerate phenotypic and functional immune reconstitution following allogeneic T-cell-depleted bone marrow transplantation in mice.     

弓形虫感染对雌鼠性器官凋亡相关蛋白Bax和Bcl-2表达的影响

目的 采用弓形虫感染雌性小鼠,观察弓形虫对卵巢、输卵管、子宫、阴道等性器官组织细胞中凋亡相关蛋白Bax、Bcl-2表达的影响,分析和探讨凋亡调控蛋白bax和bcl-2的表达是否与生殖毒性有关.方法 10周龄的处女鼠18只,随机分为感染组和正常对照组,9只/组.感染组腹腔注射纯化弓形虫速殖子0.2ml(160个/只),正...     

The immunotherapeutic effect of dendritoc cells vaccine modified with interleukin—18 gene and tumor cell lysate on mice with pancreatic carcinoma

AIM：To estimate the effect of a therapeutic vaccine against pancreatic carcinoma based on dendritic cell(DC)vaccine modified with tumor lysate and Interleukin-18 gene.METHODS:The BALB/C mice model of pancreatic arcinoma was induced with DMBA,DCvaccine was construted through pulsed with tumor lysate and transfected by the recombinant adenoviral vector encoding IL-18gene.The immnotherapeutic effects of DC vaccine on mice with pancreatic carcinoma were assessed (divided intoD-IL18-Lysate group,DC-Lysate group,DC-IL18 group,DC group,PBSgroup).RESULTS:After vaccination of the DC vaccine,the concentration of IL-18and IFN-γwere 2161&#177;439ng&#183;L^-1and435&#177;72ng&#183;L^-1inDC-IL18-Lysate group and there was significant difference compared with other groups(P&lt;0.01)After vaccination of the DCcvaccine,the transplanted tumors were observed on 30days inDC-Lysate groups.on 16daysinDC-IL18groups.on3days in control group,but mice remained tumor-free for at least50days in DC-IL18-Lysate group and there was significant difference between DC-IL18-Lysate group and other groups(P&lt;0.01).The median survival exceeds62days in DC-IL18-Lysate group.But the medsian surival was 48.6days in DC-Lysate group,33days in DC-IL-18group,17days in PBSgroup.The survival period was obviously prolonged in DC-IL18-Lysate group than in other groups(P&lt;0.05,P&lt;0.01).The weight of pancreatic tumor was0.22&#177;0.083ginDC-IL18-Lysate group,1.45&#177;0.74ginDC-Lysate group,1.89&#177;1.34gin DC-IL18group,3.0&#177;1.6ginDCgroup,2.9&#177;2.0ginPBSgroup and the weight of tumor obviously reduced in DC-IL-18-Lysate group than in other groups(P&lt;0.05,P&lt;0.01).CONCLUSION:DC vaccine modified with tumo lysate and Interleukin-18gene can induce a specific and effective immune response against pancreatic cancinoma,cell.     

Infection of mice by a Toxoplasma gondii isolate from an AIDS patient: virulence and activation of hosts' immune responses are independent of parasite genotype

Virulence of a Toxoplasma gondii isolate from an AIDS patient (designated as PTN) was compared with that of PLK, a variant of P-strain. Virulence was assessed in term of host survival upon inoculation in different strains of mice. All C57BL/6 mice died of acute toxoplasmosis by 7-10 days following intraperitoneal infection with 1 x 105 tachyzoites of PTN and 40% of BALB/c died on day 23 of infection, whereas 100% CBA/J infected with the same dose of PTN survived, as did outbred Swiss Webster mice. All C57BL/6, BALB/c, CBA/J, or Swiss Webster died of acute toxoplasmosis by 3-9 days postinfection upon inoculation with same dose of tachyzoites of the PLK strain. Further studies in CBA/J mice demonstrated that mice infected with PTN elicited a significantly higher lymphoproliferative response to crosslinked anti-CD3 mAb or Con A than PLK infected mice, and augmented production of TNFalpha, lower levels of nitrite and a higher number of NK cells. Genetical analysis indicated that both PLK and PTN strains of T. gondii are from type ll. Interestingly, being of the same genotype, the later showed less virulence upon inoculation in mice and had greater capacity to activate host immune system than the PLK strain.     

Efficient, low-cost protein factories: expression of human adenosine deaminase in baculovirus-infected insect larvae.

Human adenosine deaminase (EC 3.5.4.4), a key purine salvage enzyme essential for immune competence, has been overproduced in Spodoptera frugiperda cells and in Trichoplusia ni (cabbage looper) larvae infected with recombinant baculovirus. The coding sequence of human adenosine deaminase was recombined into a baculovirus immediately downstream from the strong polyhedrin gene promoter. Approximately 60 hr after infection of insect cells with the recombinant virus, maximal levels of intracellular adenosine deaminase mRNA, protein, and enzymatic activity were detected. The recombinant human adenosine deaminase represented 10% of the total cellular protein and exhibited a specific activity of 70 units/mg of protein in crude homogenate. This specific activity is 70-350 times greater than that exhibited by the enzyme in homogenates of the two most abundant natural sources of human adenosine deaminase, thymus and leukemic cells. When the recombinant virus was injected into insect larvae, the maximum recombinant enzyme was produced 4 days postinfection and represented about 2% of the total insect protein with a specific activity of 10-25 units/mg of protein. The recombinant human adenosine deaminase was purified to homogeneity from both insect cells and larvae and demonstrated to be identical to native adenosine deaminase purified from human cells with respect to molecular weight, interaction with polyclonal anti-adenosine deaminase antibody, and enzymatic properties. A pilot purification yielded 8-9 mg of homogeneous enzyme from 22 larvae. The production of large quantities of recombinant human adenosine deaminase in insect larvae is inexpensive and rapid and eliminates the need for specialized facilities for tissue culture. This method should be applicable to large-scale production of many recombinant proteins.