Role of human endogenous retroviral long terminal repeats (LTRs) in maintaining the integrity of the human germ line

Retroviruses integrate a reverse transcribed double stranded DNA copy of their viral genome into the chromosomal DNA of cells they infect. Occasionally, exogenous retroviruses infect germ cells and when this happens a profound shift in the virus host dynamic occurs. Retroviruses maintained as hereditable viral genetic material are referred to as endogenous retroviruses (ERVs). After millions of years of co-evolution with their hosts many human ERVs retain some degree of function and a few have even become symbionts. Thousands of copies of endogenous retrovirus long terminal repeats (LTRs) exist in the human genome. There are approximately 3000 to 4000 copies of the ERV-9 LTRs in the human genome and like other solo LTRs, ERV-9 LTRs can exhibit distinct promoter/enhancer activity in different cell lineages. It has been recently reported that a novel transcript of p63, a primordial member of the p53 family, is under the transcriptional control of an ERV-9 LTR [1]. The expression of different p63 transcript isoforms has been previously shown to have an important role in replenishing cutaneous epithelial stem cells and maintaining the fidelity of the female germ line [2]. In this recent report, a novel p63 transcript, designated GTAp63, is described as specifically expressed in healthy human testes and germ cell precursors of human testes but not in testicular cancer cells. The ability of ERV-9 regulatory regions to contribute to the maintenance of male germ line stability is yet another example of how ERVs have evolved to serve an important function in the physiology of their human hosts.

Detection of VHSV IVb within the gonads of Great Lakes fish using in situ hybridization

Viral haemorrhagic septicaemia virus (VHSV) genotype IVb was recently detected as the cause of numerous mortality events in Great Lakes fish. In situ hybridization was used to examine the gonads from 13 fish, including freshwater drum Aplodinotus grunniens and muskellunge Esox masquinongy that were infected naturally, as well as rainbow trout Oncorhynchus mykiss and fathead minnows Pimphales promelas, which were experimentally infected. Although the ovaries and testes of fish infected by VHSV IVb had few lesions, viral RNA was present in the ovaries of the rainbow trout and fathead minnow and was abundant in the gonads of muskellunge and in the ovaries of freshwater drum. Viral RNA was present mainly surrounding yolk vacuoles/granules or adjacent to the germinal vesicle, with lesser amounts found within the germinal vesicle, in the mesovarium and/or tunica albuginea and blood vessels of the ovary. Viral RNA was also found in and surrounding primary and secondary spermatocytes of the muskellunge.

The effect of Houttuynia cordata injection on pseudorabies herpesvirus (PrV) infection in vitro

CONTEXT

Pseudorabies herpesvirus (PrV) belongs to the Alphaherpesvirinae. Piglets infected with PrV die within a few days. Development of effective antiviral agents is one alternative or complementary method to prevent PrV infection. Houttuynia cordata Thunb. (Saururaceae), H. cordata, a traditional Chinese medicine, is often used to relieve lung abnormal symptoms, infectious disease, refractory hemoptysis and malignant pleural effusion in China.

OBJECTIVE

The present study aimed to investigate the effect of H. cordata injection on cell infection by PrV using Vero cells (a monkey kidney cell line) and swine testis cells (ST) as models.

MATERIALS AND METHODS

The infectivity of PrV was determined by plaque assays when H. cordata was applied to the virus, to the virus infected cells, and to the cells prior to infection. The genomic DNA copies post-drug treatment were confirmed by PCR and reverse transcription PCR. The cell apoptosis caused by the virus was analyzed.

RESULTS

H. cordata efficiently inhibited cell infection after incubating the drug with PrV. Nevertheless, H. cordata was more efficient in Vero cells than in ST cells in terms of its inhibitory effect. Low-dosage drug inhibited cell apoptosis induced by PrV; nevertheless, high-dosage drug alone resulted in cell apoptosis.

DISCUSSION AND CONCLUSION

H. cordata has a direct inhibitory activity against PrV in vitro. H. cordata may be used as an anti-PrV agent or combined with other anti-PrV agents. PrV infection induces cell apoptosis and H. cordata inhibits cell infection. The optimal administration dosage of H. cordata should be taken into account in the future, because high-dosage H. cordata alone causes cell apoptosis.

Avian bornavirus is present in many tissues of psittacine birds with histopathologic evidence of proventricular dilatation disease

Proventricular dilatation disease (PDD) is a neurologic disease of psittacine birds suspected to be caused by a recently identified Avian bornavirus (ABV). In the current report, data supporting the causal association of ABV with PDD are presented. Immunohistochemistry (IHC) with rabbit polyclonal antiserum raised against ABV nucleocapsid protein was used to identify cell and organ distribution of viral antigen. The ABV antigen was most consistently detected in brain, spinal cord, adrenal gland, pancreas, and kidney. Histopathologic evaluation was correlated with ABV-specific polymerase chain reaction (PCR) and immunohistochemical tests in multiple tissues from 16 psittacine birds with and without PDD. Using histopathologic diagnosis as the gold standard, the sensitivity and specificity of IHC for ABV antigens were found to be 100% and 100%, respectively. Many more tissues were positive for ABV RNA by reverse transcription PCR than were positive for pathologic changes or viral antigens by IHC, indicating the presence of subclinical or asymptomatic infection at many sites.

Introduction of a foreign gene into zebrafish and medaka cells using adenoviral vectors

Viral vectors represent a tractable system that can efficiently introduce an exogenous gene into different target cells and are thus a potentially powerful genetic manipulation tool. In our current study, we investigated the infection efficiency of mammalian virus vectors, adenoviruses (Ads), adeno-associated viruses, and lentiviruses to the Sertoli cell line and the newly established cell line from a single embryo in zebrafish. Among the viral vectors tested, Ads showed the highest infection efficiency of 10(7)-10(8) green fluorescent protein-transducing units (gtu)/mL in zebrafish cells. In addition, the adenoviral vector was also infected at 10(5) gtu/mL in the medaka testicular somatic cell line that was established from the testes of p53-deficient mutant. Further, we found that Ads could successfully infect cultured male zebrafish germ cells. Our results thus indicate that the adenoviral vector could be used as a chromosomally nonintegrating vector system in zebrafish.

Structural and quantitative expression analyses of HERV gene family in human tissues

Human endogenous retroviruses (HERVs) have been implicated in the pathogenesis of several human diseases as multi-copy members in the human genome. Their gene expression profiling could provide us with important insights into the pathogenic relationship between HERVs and cancer. In this study, we have evaluated the genomic structure and quantitatively determined the expression patterns in the env gene of a variety of HERV family members located on six specific loci by the RetroTector 10 program, as well as real-time RT-PCR amplification. The env gene transcripts evidenced significant differences in the human tumor/normal adjacent tissues (colon, liver, uterus, lung and testis). As compared to the adjacent normal tissues, high levels of expression were noted in testis tumor tissues for HERV-K, in liver and lung tumor tissues for HERV-R, in liver, lung, and testis tumor tissues for HERV-H, and in colon and liver tumor tissues for HERV-P. These data warrant further studies with larger groups of patients to develop biomarkers for specific human cancers.

OVEX1, a novel chicken endogenous retrovirus with sex-specific and left-right asymmetrical expression in gonads

BACKGROUND

In chickens, as in most birds, female gonad morphogenesis is asymmetrical. Gonads appear first rather similarly, but only the left one undergoes full differentiation and gives rise to a functional ovary. The right gonad, in which the cortex does not develop, remains restricted to the medulla and finally regresses. Opportunity was taken of this left-right asymmetry to perform a suppression subtractive hybridization screening to select for transcripts preferentially expressed in the developing left ovary as compared to the right one, and thus identify genes that are potentially involved in the process of ovarian differentiation.

RESULTS

One of these transcripts, named Ovex1 according to its expression profile, corresponds to an endogenous retrovirus that has not been previously characterized. It is transcribed as full-length and singly spliced mRNAs and contains three uninterrupted open reading frames coding potentially for proteins with homology to Gag and Pro-Pol retroviral polyproteins and a third protein showing only a weak similarity with Env glycoproteins. Ovex1 is severely degenerated; it is devoid of typical long terminal repeats and displays some evidence of recombination. An orthologous Ovex1 locus was identified in the genome of zebra finch, a member of a different bird order, and similar sequences were detected in turkey, guinea fowl, and duck DNA. The relationship between these sequences follows the bird phylogeny, suggesting vertical transmission of the endogenous retrovirus for more than 100 million years. Ovex1 is transcribed in chicken gonads with a sex-dependent and left-right asymmetrical pattern. It is first expressed in the cortex of the left indifferent gonads of both sexes. Expression is transient in the left testis and absent in the right one. In developing ovaries, Ovex1 transcription increases sharply in the left cortex and is weakly detected in the medulla. After folliculogenesis, Ovex1-expressing cells constitute the follicular granulosa cell layer. Ovex1 expression highlights a striking desquamation process that leads to profound cortical remodeling associated with follicle morphogenesis.

CONCLUSION

Evidence for a selection pressure at the protein level suggests that this endogenous retrovirus, expressed in the ovarian supporting cell lineage, might play an active role in bird ovarian physiology.

Presence of corticotrophin-releasing factor and/or tyrosine hydroxylase in cells of a neural brain-testicular pathway that are labelled by a transganglionic tracer

Our laboratory has shown that male testosterone levels are not solely controlled by the release of hypothalamic gonadotrophin-releasing hormone and pituitary luteinising hormone, but are also regulated by a multisynaptic pathway connecting the brain and the testis that interferes with the testosterone response to gonadotrophins. This pathway, which is independent of the pituitary gland, is activated by an i.c.v. injection of either the stress-related peptide corticotrophin-releasing factor (CRF) or of beta-adrenoceptor agonists, both of which alter androgen release and decrease levels of the peripheral-type benzodiazepine receptor and the steroidogenic acute regulatory protein within Leydig cells. Our original studies used the retrograde transganglionic tracer pseudorabies virus (PRV) to map progression of the virus from the testes to upper brain levels. The present study aimed to extend this work by identifying the regions where CRF and catecholamine neurones represented components of the stress-activated, brain-testicular pathway that prevents testosterone increases. To this end, anaesthetised adult male rats received an intra-testicular injection of PRV. Using immunofluorescence, we identified co-labelling of PRV and either CRF or tyrosine hydroxylase (TH), the enzyme responsible for biogenic amine synthesis. Co-labelling of PRV and CRF was found in the bed nucleus of the stria terminalis, the paraventricular nucleus of the hypothalamus (PVN) and the central amygdala. Co-labelling of PRV and TH was found in the PVN, substantia nigra, A7/Kölliker-Fuse area, area of A5, locus coeruleus, nucleus of solitary tract, area of C3, area of C2 and the area of C1/A1. These results indicate that most cell groups of the ventral noradrenergic pathway have neurones that are a part of the brain-testicular pathway. This suggests that the stress hormones CRF and catecholamines may act as neurotransmitters that signal the pathway to inhibit increases in plasma testosterone levels.

Retrovirus-mediated in vitro gene transfer into chicken male germ line cells

Chicken testicular cells, including spermatogonia, transplanted into the testes of recipient cockerels sterilized by repeated γ-irradiation repopulate the seminiferous epithelium and resume the exogenous spermatogenesis. This procedure could be used to introduce genetic modifications into the male germ line and generate transgenic chickens. In this study, we present a successful retroviral infection of chicken testicular cells and consequent transduction of the retroviral vector into the sperm of recipient cockerels. A vesicular stomatitis virus glycoprotein G-pseudotyped recombinant retroviral vector, carrying the enhanced green fluorescent protein reporter gene was applied to the short-term culture of dispersed testicular cells. The efficiency of infection and the viability of infected cells were analyzed by flow cytometry. No significant CpG methylation was detected in the infected testicular cells, suggesting that epigenetic silencing events do not play a role at this stage of germ line development. After transplantation into sterilized recipient cockerels, these retrovirus-infected testicular cells restored exogenous spermatogenesis within 9 weeks with approximately the same efficiency as non-infected cells. Transduction of the reporter gene encoding the green fluorescent protein was detected in the sperms of recipient cockerels with restored spermatogenesis. Our data demonstrate that, similarly as in mouse and rat, the transplantation of retrovirus-infected spermatogonia provides an efficient system to introduce genes into the chicken male germ line.

Testicular Hypoplasia in a Bull Persistently Infected with Bovine Diarrhoea Virus

A bull aged 16 months with bilateral testicular hypoplasia and azoospermia was persistently infected with bovine viral diarrhoea virus (BVDV). Viral antigen was detected in serum and semen by ELISA, but the animal was serologically negative. After slaughter, the genital tract was examined histopathologically and by immunohistochemistry, including double immunolabelling with BVDV antibody and either S-100 antibody (for Sertoli cells) or ferritin antibody (for Leydig cells). The seminiferous tubules of both testes were lined by a single layer of Sertoli cells and the germinal epithelium was completely absent except for a few remaining spermatogonia. BVDV antigen was demonstrated (1) in the media of arterial vessel walls of the testis, epididymis, urethra, prostate, and vesicular and bulbourethral glands, (2) in epithelial cells of the ductus epididymidis, the accessory glands and the urethra, and (3) in the testis, mainly in Sertoli cells and to a lesser extent in the spermatogonia that remained, but not in Leydig cells. The testicular hypoplasia was possibly linked to the BVDV infection.

Major amino acid sequence variants of viral vascular endothelial growth factor are functionally equivalent during Orf virus infection of sheep skin

Orf virus infection causes a contagious pustular dermatitis characterized by extensive vascular changes that have been linked to a virally encoded vascular endothelial growth factor (VEGF). The VEGF genes of different strains of orf virus can vary extensively in amino acid sequence. Functional analyses of two major variant VEGF proteins derived from orf virus strains, NZ2 and NZ7, have revealed quantitative differences in biological activities and receptor binding specificities suggesting that these viral VEGFs could have different roles in the pathology of orf virus infection. In this study, we show that both orf virus strains express equivalent levels of the viral VEGF variants and during infection of sheep skin induce comparable levels of vascularization, edema, epidermal rete ridge and scab formation. Recombinants of orf virus NZ2 and NZ7 strains in which the variant VEGF genes were disrupted showed markedly reduced vascular changes and evidence of partially attenuated viral growth. These results demonstrate that despite substantial differences in sequence and biological activity in vitro, these virally expressed virulence factors are functionally equivalent in their natural host, contributing equally to orf virus pathology.

Endogenous retrovirus expression in testis and epididymis

ERVs (endogenous retroviruses), which comprise 8–10% of mouse and human genomes, are present in thousands of copies, ranging in size from complete 9 kb virus to truncated partial sequences. Despite well-documented differential expression of ERVs in normal and diseased tissues, their biological significance remains controversial. Work in this laboratory revealed remarkably high ERV expression in mouse epididymis, but not in testis. Similar early studies revealed expression of human ERV-E4.1 in both testis and epididymis, but expression of other HERVs (human ERVs) was not examined. Using degenerate primers to conserved regions of reverse transcriptase specific for each of nine HERV families, we have detected expression of six HERV families in epididymis and three in testis. Differential HERV expression may reflect the fully differentiated state of epididymal epithelium in contrast with the immature germ cell population in the testis. These two tissues may therefore lay the groundwork not only for understanding the influence of cellular differentiation on HERV expression, but also to reveal HERVs that are routinely exposed to sperm.

A point mutation in the putative ATP binding site of the pseudorabies virus US3 protein kinase prevents Bad phosphorylation and cell survival following apoptosis induction

The multifunctional US3 protein kinase is conserved among alphaherpesviruses. Like the herpes simplex virus US3 protein kinase, the pseudorabies virus (PRV) US3 protein confers resistance against apoptosis. In the current report, we introduced a point mutation in the putative ATP binding site of the PRV US3 protein kinase. We found that, in contrast to the wild type PRV US3, the point-mutated PRV US3 does not protect cells from apoptosis induced by PRV infection or staurosporine treatment. In addition, we found that the presence of wild type PRV US3, but not of the point-mutated PRV US3, results in phosphorylation of the pro-apoptotic Bad protein in PRV-infected ST and HEp-2 cells. In PRV-infected ST cells, but not in HEp-2 cells, an additional, US3- and phosphorylation-independent alteration of Bad could be observed. These results suggest that the kinase activity of the US3 protein of PRV is crucial to protect cells from apoptotic cell death during infection, at least partly by leading to phosphorylation of the pro-apoptotic Bad protein.

The testis and epididymis are productively infected by SIV and SHIV in juvenile macaques during the post-acute stage of infection

Background

Little is known about the progression and pathogenesis of HIV-1 infection within the male genital tract (MGT), particularly during the early stages of infection.

Results

To study HIV pathogenesis in the testis and epididymis, 12 juvenile monkeys (Macacca nemestrina, 4–4.5 years old) were infected with Simian Immunodeficiency Virus mac 251 (SIV_mac251) (n = 6) or Simian/Human Immunodeficiency Virus (SHIV_mn229) (n = 6). Testes and epididymides were collected and examined by light microscopy and electron microscopy, at weeks 11–13 (SHIV) and 23 (SIV) following infection. Differences were found in the maturation status of the MGT of the monkeys, ranging from prepubertal (lacking post-meiotic germ cells) to post-pubertal (having mature sperm in the epididymal duct). Variable levels of viral RNA were identified in the lymph node, epididymis and testis following infection with both SHIV_mn229 and SIV_mac251. Viral protein was detected via immunofluorescence histochemistry using specific antibodies to SIV (anti-gp41) and HIV-1 (capsid/p24) protein. SIV and SHIV infected macrophages, potentially dendritic cells and T cells in the testicular interstitial tissue were identified by co-localisation studies using antibodies to CD68, DC-SIGN, αβTCR. Infection of spermatogonia, but not more mature spermatogenic cells, was also observed. Leukocytic infiltrates were observed within the epididymal stroma of the infected animals.

Conclusion

These data show that the testis and epididymis of juvenile macaques are a target for SIV and SHIV during the post-acute stage of infection and represent a potential model for studying HIV-1 pathogenesis and its effect on spermatogenesis and the MGT in general.

Susceptibility of human testis to human immunodeficiency virus-1 infection in situ and in vitro

Semen represents the main vector for human immunodeficiency virus (HIV) dissemination worldwide and has been shown to harbor replication-competent virus despite otherwise effective highly active anti-retroviral therapy, which achieves undetectable viral load in plasma. Despite this, the origin of seminal HIV particles remains unclear, as does the question of whether the male genital tract organs contribute virus to semen. Here we investigated the presence of HIV receptors within the human testis using immunohistochemistry and quantitative real-time polymerase chain reaction. We also analyzed the infectivity of a dual tropic HIV-1 strain in an organotypic culture, as well as the impact of viral exposure on testosterone production. Our study establishes that CXCR4+, CCR5+, CD4+, and DC-SIGN+ cells are present within the interstitial tissue of human testis and that these molecules persist throughout our organotypic culture. Our data also reveal that the human testis is permissive to HIV-1 and supports productive infection, leaving testosterone production apparently unaffected. Infected cells appeared to be testicular macrophages located within the interstitial tissue. That the testis itself represents a potential source of virus in semen could play a role in preventing viral eradication from semen because this organ constitutes a pharmacological sanctuary for many current antiretrovirals.

Noncytopathic bovine viral diarrhea virus can persist in testicular tissue after vaccination of peri-pubertal bulls but prevents subsequent infection

The objectives of this research were to evaluate the risk of prolonged testicular infection as a consequence of vaccination of peri-pubertal bulls with a modified-live, noncytopathic strain of BVDV and to assess vaccine efficacy in preventing prolonged testicular infections after a subsequent acute infection. Seronegative, peri-pubertal bulls were vaccinated subcutaneously with an approximate minimum immunizing dose or a 10x standard dose of modified-live, noncytopathic BVDV or were maintained as unvaccinated controls. Forty-nine days after vaccination, all bulls were intranasally inoculated with a noncytopathic field strain of BVDV. Semen and testicular biopsies collected after vaccination and challenge were assayed for BVDV using virus isolation, reverse transcription-nested PCR, or immunohistochemistry and the identity of viral strains was determined by nucleotide sequencing of PCR products. The vaccine strain of BVDV was detected in testicular tissue of vaccinated bulls as long as 134 days after immunization. Prolonged testicular infections with the challenge strain were detected only in unvaccinated bulls as long as 85 days after challenge. Whereas vaccination caused prolonged testicular infection in some bulls, it did prevent subsequent infection of testicular tissue with the challenge strain. This research demonstrates that subcutaneous vaccination of naïve, peri-pubertal bulls with a noncytopathic, modified-live strain of BVDV can result in prolonged viral replication within testicular tissue. The risk for these prolonged testicular infections to cause venereal transmission of BVDV or subfertility is likely to be low but requires further investigation.

In vivo gene transfer into the testis by electroporation and viral infection--a novel way to study testis and sperm function

The study of gene function in testis and sperm has been greatly assisted by creation of transgenic mice by injection of a transgene into the fertilised egg. However this approach is costly and laborious and is not applicable to other species of importance for the study of sperm function, such as the hamster. We have investigated alternative ways of expressing transgenes in mouse and hamster testis and sperm by in vivo gene transfer. DNA expression constructs were introduced into the testis by injection of DNA followed by electroporation, or by injection of a lentiviral vector. Expression of fluorescent proteins was assessed by fluorescence microscopy. In vivo gene transfer by electroporation led to expression of a fluorescent reporter protein and a fluorescently tagged version of sperm protein phospholipase C zeta in hamster and mouse testis and epididymal sperm. In vivo gene transfer by lentiviral infection led to high level expression of a fluorescent reporter protein in male germ cells. In conclusion, in vivo gene transfer offers a novel way to study gene function in testis and sperm and may also have potential as a way of creating transgenic versions of important model organisms such as the hamster.

At least 50% of human-specific HERV-K (HML-2) long terminal repeats serve in vivo as active promoters for host nonrepetitive DNA transcription

We report the first genome-wide comparison of in vivo promoter activities of a group of human-specific endogenous retroviruses in healthy and cancerous germ line tissues. To this end, we employed a recently developed technique termed genomic repeat expression monitoring. We found that at least 50% of human-specific long terminal repeats (LTRs) possessed promoter activity, and many of them were up- or downregulated in a seminoma. Individual LTRs were expressed at markedly different levels, ranging from approximately 0.001 to approximately 3% of the housekeeping beta-actin gene transcript level. We demonstrated that the main factors affecting the LTR promoter activity were the LTR type (5'-proviral, 3' proviral, or solitary) and position with regard to genes. The averaged promoter strengths of solitary and 3'-proviral LTRs were almost identical in both tissues, whereas 5'-proviral LTRs displayed two- to fivefold higher promoter activities. The relative content of promoter-active LTRs in gene-rich regions was significantly higher than that in gene-poor loci. This content was maximal in those regions where LTRs "overlapped" readthrough transcripts. Although many promoter-active LTRs were mapped near known genes, no clear-cut correlation was observed between transcriptional activities of genes and neighboring LTRs. Our data also suggest a selective suppression of transcription for LTRs located in gene introns.

Male germ-line cells are at risk following direct-injection retroviral-mediated gene transfer in utero

The recent observation of vector sequences in the semen of men undergoing clinical gene therapy for hemophilia has highlighted the need to evaluate the risk of inadvertent germ-line transduction in a clinically relevant animal model. In the present study, we used three different approaches to investigate whether the germ line is at risk of inadvertent alteration following in utero retroviral gene transfer in the clinically relevant, random-bred sheep model. First, we conducted breeding studies. All organs from the 10 resultant offspring were devoid of proviral DNA, suggesting that the germ line had not been altered. As a second approach, we performed PCR on gradient-enriched, forensically purified sperm cells from in utero-transduced rams. The purified sperm cells from 6 of 19 of these rams were PCR positive for provirus, providing compelling evidence that the germ line had been transduced. As a third approach, we performed immunohistochemistry on sections of the testis from in utero-transduced sheep. Numerous somatic cells and very low levels of germ cells within the male reproductive tissues were transduced. In conclusion, our analysis on over 3 x 10(9) sperm cells suggests that the direct-injection approach employed in these studies may result in the inadvertent transduction of very low numbers of male germ cells.

Inadvertent Germline Transmission of AAV2 Vector: Findings in a Rabbit Model Correlate with Those in a Human Clinical Trial

The risk of germline transmission of vector sequences in humans is a major safety concern, because the enrollment of subjects of reproductive age in early-phase clinical trials of gene transfer continues to increase. In a study of adult men with hemophilia B, adeno-associated virus serotype 2 (AAV2) delivered to the liver via the hepatic artery resulted in unexpected transient vector dissemination to the semen. Here we report that intravenous AAV2 injection in rabbits proved a useful model to assess biologic parameters of vector dissemination to the semen. Detectable vector sequences in semen disappeared in a dose-dependent and time-dependent fashion. AAV infectious particles were present only as long as day 4 after injection and were undetectable thereafter. The kinetics of vector clearance was faster in the semen fractions enriched for motile sperm than in the total semen. In addition, increased frequency of semen sampling accelerated the clearance of vector sequences from semen. Long-term follow-up, spanning hundreds of spermatogenesis cycles, showed that there was no recurrence of detectable vector sequences in semen, thus reducing the probability of inadvertent transduction of early spermatogonia not committed to differentiation at the time of vector injection. We conclude that AAV2 presents minimal germline transmission risk for humans.

Development of real-time PCRs for detection and quantitation of human MMTV-like (HML) sequences HML expression in human tissues

The human genome contains around 1000 betaretrovirus-like copies, human mouse mammary tumour virus (MMTV)-like (HML) groups 1-10, also referred to as human endogenous retrovirus "HERV-K". Despite many efforts, it is not established whether betaretroviruses, exo- or endogenous, are involved in the etiology of breast cancer, or other cancer diseases, in humans. Quantitative real-time PCR (QPCR) TaqMan-based assays for HML groups 1-7, targeting the conserved reverse transcriptase (RT) and integrase (IN) domains of the pol gene were designed. Plasmids containing the entire pol gene of HML1-7 were used as standards. The RT and IN based QPCRs could detect 10(0)-10(3) copies per PCR reaction of the plasmids. However, not all plasmids gave a signal in both RT and IN QPCRs, probably due to mismatches. Furthermore, RT and IN based HML6 specific QPCRs were developed. They were specific for amplification of transcripts for the whole HML6 group. The methods allow the monitoring in body fluids and tissues of expression of a wide range of betaretrovirus-like sequences. Betaretrovirus-like RNA was studied in normal human tissues and of HML6 in brains of multiple sclerosis (MS) patients. Brain, adrenal gland and testis had a high betaretrovirus-like expression. Multiple sclerosis plaques contained the same HML6 RNA concentration as control tissue. These assays are expected to enhance studies on involvement of betaretroviruses in physiology and disease.

Use of a modified-live vaccine to prevent persistent testicular infection with bovine viral diarrhea virus

A commercial vaccine containing modified-live bovine viral diarrhea virus (BVDV; types 1 and 2) was administered to one group of 22 peripubertal bulls 28 days before intranasal inoculation with a type 1 strain of BVDV. A second group of 23 peripubertal bulls did not receive the modified-live BVDV vaccine before intranasal inoculation. Ten of 23 unvaccinated bulls--but none of the vaccinated bulls--developed a persistent testicular infection as determined by immunohistochemistry and polymerase chain reaction. Results of this study indicate that administration of a modified-live vaccine containing BVDV can prevent persistent testicular infection if peripubertal bulls are vaccinated before viral exposure.

Presence of human papillomavirus DNA in testicular biopsies from nonobstructive azoospermic men

CONTEXT

Human papillomavirus (HPV) plays a major role in the etiology of many malignancies of diverse localization, such as uterine cervical carcinoma and its precursors. Human papillomavirus sequences have been detected throughout the male lower genitourinary tract, but the role of men as transmitters remains unclear.

OBJECTIVE

To investigate the relationship between azoospermia and the presence of HPV DNA in testicular cells.

DESIGN

One hundred eighty-five patients with azoospermia undergoing testicular biopsy were studied. Histologic study was done on formalin-fixed, paraffin-embedded samples from testicular biopsies, stained with hematoxylin-eosin. Molecular study to detect HPV sequences was performed on genomic DNA isolated from paraffin sections by standard protocols. Seven cases containing HPV sequences were studied after microdissection with PALM microlaser technology in order to determine the presence of HPV DNA sequences in different cells, as well as from seminal tubules or stromal (Leydig) cells.

RESULTS

Human papillomavirus DNA sequences were detected in testicular biopsies of 12 patients (6.48%). Human papillomavirus type 16 was the most common genotype encountered. Among the 92 patients who underwent bilateral testicular biopsy, HPV sequences were detected in 9 patients (9.78%), all of whom showed only unilateral testicular affection, more often in the left testicle (ratio, 2: 1). After microdissection, HPV DNA sequences were seen in Leydig and Sertoli cells; the presence of HPV in germinal cells could not be ruled out.

CONCLUSIONS

Leydig cells, Sertoli cells, and probably germinal cells (cases 2, 3, and 4) harbored HPV DNA sequences. Such findings have not been previously described in testicular tissue.

Orchitis: a complication of severe acute respiratory syndrome (SARS)

Severe acute respiratory syndrome (SARS) coronavirus has been known to damage multiple organs; however, little is known about its impact on the reproductive system. In the present study, we analyzed the pathological changes of testes from six patients who died of SARS. Results suggested that SARS caused orchitis. All SARS testes displayed widespread germ cell destruction, few or no spermatozoon in the seminiferous tubule, thickened basement membrane, and leukocyte infiltration. The numbers of CD3+ T lymphocytes and CD68+ macrophages increased significantly in the interstitial tissue compared with the control group (P < 0.05). SARS viral genomic sequences were not detected in the testes by in situ hybridization. Immunohistochemistry demonstrated abundant IgG precipitation in the seminiferous epithelium of SARS testes, indicating possible immune response as the cause for the damage. Our findings indicated that orchitis is a complication of SARS. It further suggests that the reproductive functions should be followed and evaluated in recovered male SARS patients.