山羊关节炎—脑炎病毒结构蛋白分析及其相应抗体在山羊体内的消长规律

对山羊关节炎－脑炎病毒（ＣＡＥＶ）结构蛋白进行了分析，主要蛋白有ＧＰ１２５、ＧＰ９０、ＧＰ７０、ＧＰ４５、Ｐ２８、Ｐ１６和Ｐ１４。同时检测了ＣＡＥＶ实验感染山羊后的ＧＰ１２５、ＧＰ９０和Ｐ２８抗体在机体内的消长情况。     

Coltivirus病毒属研究进展

Ｃｏｌｔｉｖｉｒｕｓ病毒属 (Ｃｏｌｔｉｖｉｒｕｓ ,Ｃｏｌｔｉ)为呼肠病毒科病毒 ,以科罗拉多蜱媒热病毒 (Ｃｏｌｏｒａｄｏｔｉｃｋｆｅｖｅｒｖｉｒｕｓ,ＣＴＦＶ)为代表株 ,该病毒原为环状病毒属成员 ,由于其对人有致病性 ,可引起人的发热和脑炎 ,病毒核心的衣壳表面结构     

标记抗体染色病毒空斑计数技术的研究

用细胞病变阳性（ｐｏｓｉｔｉｖｅ ｃｙｔｏｐａｔｈｏｇｅｎｉｃ ｅｆｆｅｃｔ,ＣＰＥ＋ ）病毒马立克氏病毒（Ｍａｒｅｋ＇ｓｄｉｓｅａｓｅ ｖｉｒｕｓ, ＭＤＶ）血清１,２,３ 型以及细胞病变阴性（ｎｅｇａｔｉｖｅ ｃｙｔｏｐａｔｈｏｇｅｎｉｃ ｅｆｆｅｃｔ,ＣＰＥ－ ）病毒猪瘟病毒（Ｈｏｇ ｃｈｏｌｅｒａ ｖｉｒｕｓ,ＨＣＶ）强毒与弱毒和鸡新城疫病毒（Ｎｅｗ ｃａｓｔｌｅ ｄｉｓｅａｓｅｖｉｒｕｓ． ＮＤＶ）Ｌａｓｏｔａ 毒株及其对应的异硫氢酸荧光素（ＦＩＴＣ）标记的特异抗体为试验材料,以免疫荧光抗体技术（ＦＡ）为基础、并加以改进,建立了标记抗体染色病毒空斑计数技术． 该技术不仅能克服常规病毒空斑计数技术不能计数细胞病变阴性病毒和一种样品含有两种或两种以上病毒的各自空斑数的缺点,能迅速准确计数出ＣＰＥ－ 病毒和多病毒样品中病毒各自空斑数及其空斑总数,具较高敏感性、良好的可重复性．     

TORCH综合征与先天性畸形

近年来,先天性感染引起新生儿畸形死亡的人数日益增加, Ｔ Ｏ Ｒ Ｃ Ｈ 是一组能引起先天性感染的病原微生物。１９７１ 年 Ｎａｈｍ ｉａｓ 等将引起先天性感染的病原体用英文字头命名,称为 Ｔ Ｏ Ｒ Ｃ Ｈ 感染或 Ｔ Ｏ Ｒ Ｃ Ｈ 综合征。 Ｔ 代表弓形体（ Ｔｏｘｏｐｌａｓｍ ａ ｇｏｎｄｉｉ, Ｔ Ｏ Ｘ Ｏ）, Ｏ为其它（ Ｏｔｈｅｒ,包括很多种病毒）, Ｒ 表示风疹病毒（ Ｒｕｂｅｌｌａ ｖｉｒｕｓ）, Ｃ代表巨细胞病毒（ Ｃｙｔｏｍ ｅｇａｌｏｖｉｒｕｓ, Ｃ Ｍ Ｖ）, Ｈ 表示单纯疱疹病毒（ Ｈｅｒｐｅｓ ｓｉｍ ｐｌｅｘ ｖｉｒｕｓ, Ｈ Ｓ Ｖ）。随着病原微生物学、免疫学和流行性病学研究的进展,又发现了多种能引起先天性感染的病原微生物,如水痘--带状疱疹病毒（ Ｖａｒｉｃｅｌｌａ ｚｏｓｔｅｒ ｖｉｒｕｓ, Ｖ Ｚ Ｖ）,麻疹病毒（ Ｍｅａｓｌｅｓ ｖｉｒｕｓ, Ｍ Ｖ）, 流 行性腮 腺炎 病毒（ Ｐａｒｏｔｉｔｉｓ ｖｉｒｕｓ, Ｐ Ｖ）, 人类免 疫缺 陷病毒 （ Ｈｕｍ ａｎｉｍ ｍ ｕｎｏｄｅｆｉｃｉｅｎｃｙ ｖｉｒｕｓ, Ｈ Ｉ Ｖ）,丙型肝炎病毒（ Ｈｅｐａｔｉｔｉｓ Ｃ ｖｉｒｕｓ, Ｈ Ｃ Ｖ）,人类疱疹病毒６型（ Ｈｕｍ ａｎ ｈｅｒｐｅｓ ｖｉｒｕｓ ｔｙｐｅ ６, Ｈ Ｈ Ｖ ６）,肠道病毒（ Ｅｎｔｅｒｏｖｉｒｕｓ, Ｅ Ｖ）,乙型肝炎病毒（ Ｈｅｐａｔｉｔｉｓ Ｂ ｖｉｒｕｓ, Ｈ Ｂ Ｖ）,人类乳头瘤病毒（ Ｈｕｍ ａｎ ｐａｐｉｌｌｏｍ ａｖｉｒｕｓ, Ｈ Ｐ Ｖ）, Ｅ Ｂ 病毒（ Ｅｐｓｔｅｉｎ Ｂａｒｒ ｖｉｒｕｓ, Ｅ Ｂ Ｖ）,人类微小病毒 Ｂ１９（ Ｈｕｍ ａｎ ｐａｒｖｏｖｉｒｕｓ Ｂ１９, Ｈ Ｐ Ｖ Ｂ１９）和人类嗜血细胞病毒１ 型（ Ｈ Ｔ Ｌ Ｖ １）等。 Ｔ Ｏ Ｒ Ｃ Ｈ 感染的特点是孕妇患其中任何一种疾病后,本人的症状极其轻微,或根本没有症状和特征。病原体虽不相同,却能使胎儿或新生儿出现相同或相似的临床表现,有时还很严重,甚至导致死亡。如在怀孕早期感染,则发生流产、死胎和胎儿畸形。中晚期感染,导致胎儿不同程度畸形和脏器损害。     

艾滋病疫苗

艾滋病疫苗英国剑桥ＡＸｉｓ遗传公司推出了利用嵌合病毒颗粒（ＣＶＰ）技术生产人免疫缺陷病毒或艾滋病毒（ＨＩＶ）疫苗的技术。实验室试验表明,用不同剂量的ＨＩＶＰＰ“肽嵌合病毒颗粒［ＣＶＰ—ＨＩＶ（ｇＰ“）」免疫小鼠,可使其产生大量的中和抗体。还证明,这些...     

栗疫病菌的营养体亲和性基因和dsRNAs对病毒传播的影响

研究了栗疫病菌（Ｃｒｐｈｏｎｅｃｔｒｉａｐａｒａｓｉｔｉｃａ（Ｍｕｒｒ）．Ｂａｒｒ）营养体亲和性基因及ｄｓＲＮＡ病毒对菌株间病毒特征与传播影响,试验选用已知４个ＶＣ基因座位的１５个ＶＣ基因型菌株和３种ｄｓＲＮＡ病毒,通过含病毒菌株与野生型菌株的配对培养,将病毒逐个转入不同ＶＣ基因型菌株,将不同ＶＣ基因型的含病毒菌株与具特定ＶＣ基因差异的野生型菌株配对培养,根据培养两周后野生型菌株培养性状的改变与否     

栗疫菌低毒力dsRNA与真菌病毒dsRNA的序列同源性

以我国栗疫菌［Ｃｒｙｐｈｏｎｅｃｔｒｉａ（＝Ｅｎｄｏｔｈｉａ）ｐａｒａｓｉｔｉｃａ］低毒力菌株ＥｐＣ１４０（广西）的［γ─￣３２Ｐ］ＡＴＰ末端标记ｄｓＲＮＡ作探针,与５种真菌病毒ｄｓＲＮＡ进行分子杂交。探针可与紫孢侧耳病毒（Ｐｌｅｕｒｏｔｕｓｓｅｐｉｄｕｓｖｉｕｓ）和小麦全蚀菌病毒（Ｇａｅｕｍａｎ─ｎｏｍｙｃｅｓｇｒａｍｉｎｉｓ·ｖｉｒｕｓ）的ｄｓＲＮＡ杂交,但不能与黑曲霉病毒（Ａｓｐｅｒｇｉｌｌｕｓｎｉｇｅｒｖｉｒｕｓ）、产黄青霉病毒（Ｐｅｎｉｃｉｌｌｉｕｍｃｈｒｙｓｏｇｅｎｕｍｖｉｒｕｓ）和稻瘟菌病毒（Ｐｙｒｉｃｕｌａｒｉａｏｒｙｚａｅｖｉｒｕｓ）的ｄｓＲＮＡ杂交。当以低毒力菌株ＥｐＣ３２（云南）作探针时,结果相同。     

栗菌低毒力dsRNA与协菌病毒dsRNA的序列同源性

以我国栗疫菌（Ｃｒｙｐｈｏｎｅｃｔｒｉａ（＝Ｅｎｄｏｔｈｉａ）ｐａｒａｓｉｔｉｃａ）低毒力菌株ＥｐＣ１４０（广西）的（γ－＾３２Ｐ）ＡＴＰ末端标记ｄｓＲＮＡ作探针,与５种真菌病毒ｄｓＲＮＡ进行分子杂交。探针可与紫孢侧耳病毒（Ｐｌｅｕｒｏｔｕｓ ｓａｐｉｄｕｓ ｖｉｒｕｓ）和小麦全蚀菌病毒（Ｇａｅｕｍａｎ－ｎｏｍｙｃｅｓ ｇｒａｍｉｎｉｓ．ｖｉｒｕｓ）的ｄｓＲＮＡ杂交,但不能与黑曲霉病毒（Ｐｙｒｉｃ     

猪瘟病毒及其疫苗研究进展

猪瘟病毒及其疫苗研究进展陆宇,陈建国,丁明孝（北京大学生命科学学院,北京１００８７１）ＲｅｓｅａｒｃｈＰｒｏｇｒｅｓｓｏｎＨｏｇＣｈｏｌｅｒａＶｉｒｕｓａｎｄｉｔｓＶａｃｃｉｎｅＬｕＹｕ;ＣｈｅｎＪｉａｎｇｕｏ;ＤｉｎｇＭｉｎｇｘｉａｏ（Ｃｏｌｌｅｇ...     

GC32细胞对三种虫媒病毒的敏感性研究

用胃癌细胞株ＧＣ３２,对乙型脑炎、基孔肯雅、兰加特病毒进行敏感性研究。并用ＢＨＫ２１细胞作对照,发现ＧＣ３２细胞对两种病毒的敏感性与对照细胞ＢＨＫ２１极为接近。ＢＨＫ２１和ＧＣ３２细胞对基孔肯雅、乙型脑炎和兰加特的免疫荧光实验,于感染后４８ｈ或７２ｈ都出现＋＋＋～＋＋＋＋的阳性结果。两种细胞对基孔肯雅和乙型脑炎病毒都形成空斑,ＢＨＫ２１细胞对基孔肯雅和乙型脑炎病毒的空斑形成单位分别为５．６５和５．３６;ＧＣ３２对基孔肯雅和乙型脑炎病毒的空斑形成单位分别为６．４８和５．６１。实验表明,ＧＣ３２细胞可以作为有关病毒实验的理想细胞株。     

Presence of caprine arthritis-encephalitis virus (CAEV) infected cells in flushing media following oviductal-stage embryo collection

To improve the knowledge on the risk of transmission of the caprine arthritis-encephalitis virus (CAEV) during embryo manipulations, we conducted a double-nested polymerase chain reaction (PCR) for CAEV proviral-DNA on flushing media recovered from the oviducts 48 h after the beginning of estrus and on blood from 89 donor does. Sixty-four does had negative blood and flushing media by PCR. Among the 25 CAEV infected goats (blood PCR positive), 11 were PCR flushing media positive (P < 0.01). Cell lysate from flushing media samples that were PCR positive were serially diluted 10 times at 1:100. Starting with the second 1:100 dilution all the cell lysate samples were PCR negative. The mean number of embryos recovered was not significantly different between goats with flushing media PCR positive and goats with flushing media PCR negative (6.0 +/- 5.4 versus 7.8 +/- 4.4, respectively; mean +/- S.D.) nor between goats with blood PCR positive and goats with blood PCR negative (7.0 +/- 5.0 versus 5.9 +/- 5.3; mean +/- S.D.). The presence of CAEV infected cells in oviductal flushing media from infected donor does was indicated for the first time during this study. The absence of flushing media PCR positive for goat blood PCR negative seemed to allow the use of the blood PCR test to confidently predict the absence of CAEV provirus in the oviductal fluid.     

Proviral DNA of caprine arthritis encephalitis virus (CAEV) is detected in cumulus oophorus cells but not in oocytes from naturally infected goats

The aim of this study was to determine whether oocytes taken from ovarian follicles in 123 naturally infected goats were carrying the proviral CAEV genome. Examination of DNA isolated from 190 batches of oocytes with intact cumulus cells and 190 batches of oocytes whose cumulus cells had been removed, taken from follicles of the same ovaries, demonstrated that 42/190 batches of oocytes with intact cumulus cells had the proviral CAEV genome, whereas none of the 190 batches of oocytes without cumulus cells were positive for the provirus. To confirm that the proviral genome was present in the cumulus cells and not in the oocyte cells, 586 oocytes from 56 different ovaries, were separated from their cumulus cells. The DNA was then extracted from each fraction and examined. The purity of the oocyte fraction was verified by searching for granulosa cell-specific mRNA, using RT-PCR; this was negative in all the batches of oocytes in which the cumulus cells had been removed. PCR analysis demonstrated that none of the oocytes without cumulus cells were positive, whereas 22/56 of the batches with cumulus cells were found to be positive. This study clearly demonstrates that despite being surrounded by infected cumulus cells, the oocytes are not infected, and that the enzymatic and mechanical technique for removing the cells surrounding the oocyte, as used in this study, is effective, thus enabling CAEV-free oocytes to be obtained from infected goats.     

Can caprine arthritis encephalitis virus (CAEV) be transmitted by in vitro fertilization with experimentally infected sperm?

For each of the five fertilization trials of the experiment, frozen semen was prepared for in vitro capacitation at a concentration of 1 × 10⁷ spz/ml and divided into three groups. One group was used as a control, while the two others were inoculated with 100 μl/ml of either culture medium from non-infected cells (placebo group) or cell culture medium containing virus at a concentration of 10⁵ TCID₅₀/ml (infected group). A total of 789 oocytes were used for IVF. For each of the five trials a group of oocytes were used as a non-infected control and were found to be caprine arthritis-encephalitis virus (CAEV) free. The other oocytes were divided in two equal batches. Oocytes in the first batch were in vitro fertilized with CAEV infected sperm (infected group) and the second batch were fertilized with CAEV non-infected sperm (placebo and control groups). After IVF, the zygotes of each group were washed 12 times. The CAEV genome was not detected (using RT-PCR) in the washing media of either the control or placebo groups from each trial. In contrast, the first three washing media from the infected group were consistently found to be positive for the CAEV genome (5/5), whereas subsequent washing media were CAEV-free (P < 0.05). Zygotes obtained using all semen groups tested negative for both the provirus and genome of CAEV. These results clearly show that the first four washes were sufficient to remove viral particles from CAEV infected fertilization media and that CAEV-free embryos can be produced by IVF using spermatozoa infected in vitro by CAEV.     

Sint1, a common integration site in SL3-3-induced T-cell lymphomas, harbors a putative proto-oncogene with homology to the septin gene family

The murine retrovirus SL3-3 is a potent inducer of T-cell lymphomas when inoculated into susceptible newborn mice. Previously, DNAs from twenty SL3-3-induced tumors were screened by PCR for provirus integration sites. Two out of 20 tumors demonstrated clonal provirus insertion into a common region. This region has now been isolated and characterized. The region, named SL3-3 integration site 1 (Sint1), maps to the distal end of mouse chromosome 11, corresponding to human chromosome 17q25, and may be identical to a mouse mammary tumor virus integration site in a T-cell lymphoma, Pad3. Two overlapping genomic lambda clones spanning about 35 kb were isolated and used as a starting point for a search for genes in the neighborhood of the virus integration sites. A genomic fragment was used as a hybridization probe to isolate a 3-kb cDNA clone, the expression of which was upregulated in one of two tumors harboring a provirus in Sint1. The cDNA clone is predicted to encode a protein which shows 97.0% identity to a human septin-like protein encoded by a gene which has been found as a fusion partner gene of MLL in an acute myeloid leukemia with a t(11;17)(q23;q25). Together these findings raise the possibility that a proto-oncogene belonging to the septin family, and located about 15 kb upstream of the provirus integration sites, is involved in murine leukemia virus-induced T-cell lymphomagenesis.     

Linear Amplification Mediated PCR – Localization of Genetic Elements and Characterization of Unknown Flanking DNA

Linear-amplification mediated PCR (LAM-PCR) has been developed to study hematopoiesis in gene corrected cells of patients treated by gene therapy with integrating vector systems. Due to the stable integration of retroviral vectors, integration sites can be used to study the clonal fate of individual cells and their progeny. LAM- PCR for the first time provided evidence that leukemia in gene therapy treated patients originated from provirus induced overexpression of a neighboring proto-oncogene. The high sensitivity and specificity of LAM-PCR compared to existing methods like inverse PCR and ligation mediated (LM)-PCR is achieved by an initial preamplification step (linear PCR of 100 cycles) using biotinylated vector specific primers which allow subsequent reaction steps to be carried out on solid phase (magnetic beads). LAM-PCR is currently the most sensitive method available to identify unknown DNA which is located in the proximity of known DNA. Recently, a variant of LAM-PCR has been developed that circumvents restriction digest thus abrogating retrieval bias of integration sites and enables a comprehensive analysis of provirus locations in host genomes. The following protocol explains step-by-step the amplification of both 3’- and 5’- sequences adjacent to the integrated lentiviral vector.     

Isolation and analysis of retroviral integration targets by solo long terminal repeat inverse PCR

Upon retroviral infection, the genomic RNA is reverse transcribed to make proviral DNA, which is then integrated into the host chromosome. Although the viral elements required for successful integration have been extensively characterized, little is known about the host DNA structure constituting preferred targets for proviral integration. In order to elucidate the mechanism for the target selection, comparison of host DNA sequences at proviral integration sites may be useful. To achieve simultaneous analysis of the upstream and downstream host DNA sequences flanking each proviral integration site, a Moloney murine leukemia virus-based retroviral vector was designed so that its integrated provirus could be removed by Cre-loxP homologous recombination, leaving a solo long terminal repeat (LTR). Taking advantage of the solo LTR, inverse PCR was carried out to amplify both the upstream and downstream cellular flanking DNA. The method called solo LTR inverse PCR, or SLIP, proved useful for simultaneously cloning the upstream and downstream flanking sequences of individual proviral integration sites from the polyclonal population of cells harboring provirus at different chromosomal sites. By the SLIP method, nucleotide sequences corresponding to 38 independent proviral integration targets were determined and, interestingly, atypical virus-host DNA junction structures were found in more than 20% of the cases. Characterization of retroviral integration sites using the SLIP method may provide useful insights into the mechanism for proviral integration and its target selection.     

Lack of risk of transmission of caprine arthritis-encephalitis virus (CAEV) after an appropriate embryo transfer procedure

The aim of this study was to demonstrate that embryo transfer can be used to produce CAEV-free kids from CAEV-infected biological mothers when appropriate procedure is implemented. Twenty-eight goats that had tested positive for CAEV using PCR on vaginal secretions were used as embryo donors. Embryos with intact-ZP were selected and washed 10 times; they were then frozen and used for transfer into CAEV-free recipient goats. Nineteen of the 49 recipient goats gave birth, producing a total of 23 kids. Three blood samples were taken from each recipient goat, 10 days before, during, and 10 days after parturition; these were tested for CAEV antibodies using ELISA and for CAEV proviral DNA using PCR. The mothers were then euthanized. Tissue samples were taken from the lungs, udder, and retromammary and prescapular lymph nodes. The kids were separated from their mothers at birth. Seven of them died. At 4 months of age, 16 kids were subjected to drug-induced immunosuppression. Blood samples were taken every month from birth to 4 months of age; samples were then taken on days 15, 21, and 28 after the start of the immunosuppressive treatment. The kids were then euthanized and tissue samples taken from the carpal synovial membrane, lung tissue, prescapular lymph nodes, inguinal and retromammary lymph nodes, and uterus. All samples from the 19 recipient goats and 23 kids were found to be negative for CAEV antibodies and/or CAEV proviral DNA. Under acute conditions for infection this study clearly demonstrates that embryo transfer can be safely used to produce CAEV-free neonates from infected CAEV donors.     

Detection of viral genomes of caprine arthritis-encephalitis virus (CAEV) in semen and in genital tract tissues of male goat

The aim of this study was to determine the infectious status of semen and genital tract tissues from male goat naturally infected with the caprine lentivirus. Firstly, polymerase chain reaction (PCR) was used to detect the presence of CAEV proviral-DNA in the circulating mononuclear cells, semen (spermatozoa and non-spermatic cells), and genital tract tissues (testis, epididymis, vas deferens, and vesicular gland) of nine bucks. RT-PCR was used to detect the presence of CAEV viral RNA in seminal plasma. Secondly, in situ hybridization was performed on PCR-positive samples from the head, body, and tail of the epididymis. CAEV proviral-DNA was identified by PCR in the blood cells of 7/9 bucks and in non-spermatic cells of the seminal plasma of 3/9 bucks. No CAEV proviral-DNA was identified in the spermatozoa fraction. The presence of CAEV proviral-DNA in non-spermatic cells and the presence of CAEV in the seminal plasma was significantly higher (p<0.01) in bucks with PCR-positive blood. Two of the three bucks with positive seminal plasma cells presented with at least one PCR-positive genital tract tissue. Proviral-DNA was found in the head (3/9), body (3/9), and tail (2/9) of the epididymis. In situ hybridization confirmed the presence of viral mRNA in at least one of each of these tissues, in the periphery of the epididymal epithelium. This study clearly demonstrates the presence of viral mRNA and proviral-DNA in naturally infected male goat semen and in various tissues of the male genital tract.     

Transmission of Human T-Cell Leukemia Virus Type 1 to Mice

Human T-cell leukemia virus type 1 (HTLV-1) is associated with adult T-cell leukemia/lymphoma, HTLV-1-associated myelopathy/tropical spastic paraparesis, and other diseases. For prevention of the transmission of HTLV-1 and manifestation of these diseases, a small-animal model, especially a mouse model, would be useful. We injected HTLV-1-producing T cells (MT-2) intraperitoneally into neonatal C3H/HeJ mice. While the antibody against HTLV-1 antigens was not detectable in C3H/HeJ mice, HTLV-1 provirus was frequently detected in the spleen, lymph nodes, and thymus by PCR. HTLV-1 provirus was present at the level of 0 to 30 molecules in 10⁵ spleen cells at the age of 15 weeks. In addition, a 59-bp flanking sequence of the HTLV-1 integration site was amplified from the spleen DNA by linker-mediated PCR and was confirmed to be derived from the mouse genome. HTLV-1 provirus was found in the T-cell fraction of the mouse spleen. These results indicate that mice can be infected by HTLV-1 and could serve as an animal model for the study of HTLV-1 infection and its pathogenesis in vivo.     

Cellular recombination pathways and viral terminal repeat hairpin structures are sufficient for adeno-associated virus integration in vivo and in vitro.

The human parvovirus adeno-associated virus (AAV) is unique in its ability to target viral integration to a specific site on chromosome 19 (ch-19). Recombinant AAV (rAAV) vectors retain the ability to integrate but have apparently lost this ability to target. In this report, we characterize the terminal-repeat-mediated integration for wild-type (wt), rAAV, and in vitro systems to gain a better understanding of these differences. Cell lines latent for either wt or rAAV were characterized by a variety of techniques, including PCR, Southern hybridization, and fluorescence in situ hybridization analysis. More than 40 AAV-rAAV integration junctions were cloned, sequenced, and then subjected to comparison and analysis. In both immortalized and normal diploid human cells, wt AAV targeted integration to ch-19. Integrated provirus structures consisted of head-to-tail tandem arrays with the majority of the junction sequences involving the AAV inverted terminal repeats (ITRs). No complete viral ITRs were directly observed. In some examples, the AAV p5 promoter sequence was found to be fused at the virus-cell junction. Data from dot blot analysis of PCR products were consistent with the occurrence of inversions of genomic and/or viral DNA sequences at the wt integration site. Unlike wt provirus junctions, rAAV provirus junctions mapped to a subset of non-ch-19 sequences. Southern analysis supported the integration of proviruses from two independent cell lines at the same locus on ch-2. In addition, provirus terminal repeat sequences existed in both the flip and flop orientations, with microhomology evident at the junctions. In all cases with the exception of the ITRs, the vector integrated intact. rAAV junction sequence data were consistent with the occurrence of genomic rearrangement by deletion and/or rearrangement-translocation at the integration locus. Finally, junctions formed in an in vitro system between several AAV substrates and the ch-19 target site were isolated and characterized. Linear AAV substrates typically utilized the end of the virus DNA substrate as the point of integration, whereas products derived from AAV terminal repeat hairpin structures in the presence or absence of Rep protein resembled AAV-ch-19 junctions generated in vivo. These results describing wt AAV, rAAV, and in vitro integration junctions suggest that the viral integration event itself is mediated by terminal repeat hairpin structures via nonviral cellular recombination pathways, with specificity for ch-19 in vivo requiring additional viral components. These studies should have an important impact on the use of rAAV vectors in human gene therapy.