For xenotransplantation, the transplantation of animal cells, tissues and organs into human recipients, to date, pigs are favored as potential donors. Beside ethical, immunological, physiological and ...technical problems, the microbiological safety of the xenograft has to be guaranteed. It will be possible to eliminate all of the known porcine microorgansims in the nearby future by vaccinating or specified pathogen-free breeding. Thus, the main risk will come from the porcine endogenous retroviruses (PERVs) which are present in the pig genome as proviruses of different subtypes. PERVs will therefore be transmitted, with the xenograft, to the human recipient. PERVs can infect numerous different types of human primary cells and cell lines in vitro and were shown to adapt to these cells by serial passaging on uninfected cells. Furthermore, PERVs have high homology to other retroviruses, such as feline leukemia virus (FeLV) or murine leukemia virus (MuLV), which are known to induce tumors or immunodeficiencies in the infected host. To evaluate the potential risk of a trans-species transmission of PERV in vivo, naive and immunosuppressed rats, guinea pigs and minks were inoculated with PERV and screened over a period of 3 months for an antibody reaction against PERV proteins or for the integration of proviral DNA into the genomic DNA of the host's cells. Furthermore, we inoculated three different species of non-human primates, rhesus monkey (
Macaca mulatta), pig-tailed monkey (
Macaca nemestrina) and baboon (
Papio hamadryas) with high titers of a human-adapted PERV. To simulate a situation in xenotransplantation, the animals received a daily triple immunosuppression using cyclosporine A, methylprednisolone and RAD, a rapamycin derivative, presently under development by Novartis. None of the small laboratory animals or the non-human primates showed production of antibodies against PERV or evidence of integration of proviral DNA in blood cells or cells of several organs, 3 months after virus inoculation, despite the observation that cells of the animals used in the experiment were infectible in vitro. This apparent difference in the outcome of the in vitro and the in vivo data might be explained by an efficient elimination of the virus by the innate or adaptive immunity of the animals.
Porcine xenotransplants may offer a potential solution to the problem posed by the limited supply of allotransplants. However, xenotransplantation may be associated with the risk of transmission of ...microorganisms, in particular of porcine endogenous retroviruses (PERVs) that are an integral part of the porcine genome and able to infect human cells in vitro. Possible strategies to prevent virus transmission include the development of PERV knockout animals or of effective vaccines. When antisera prepared against the main structural proteins of PERV were screened, a goat antiserum against the recombinant ectodomain of the transmembrane envelope protein p15E was found to neutralize PERV infectivity. Epitope mapping using overlapping peptides revealed two epitopes, E1 (GPQQLEK) and E2 (FEG
WFN
). These sequences are identical for all PERVs and are highly conserved among all gammaretroviruses. Interestingly, antibodies isolated from AIDS patients and specific for sequences of HIV-1 partially homologous with E2 (Mab4E10, LWN
WFN
) or located in close proximity to E2 (Mab2F5, ELDKWA) are known to neutralize several strains of HIV-1. It is the first report showing epitope mapping of gammaretrovirus-specific neutralizing antibodies and demonstrating similarity to corresponding epitopes in HIV. These domains of the transmembrane proteins of different retroviruses are an effective target for neutralizing antibodies and may be a useful antigen to create an antiretroviral vaccine.
Transplantation of porcine xenografts into human recipients is a realistic option to overcome the growing worldwide shortage of suitable allogeneic organs. However, there remains the risk of ...infection by porcine endogenous retroviruses (PERVs) that cannot be eliminated like that by other microorganisms by breeding pigs under specified pathogen-free conditions. To reduce the release of PERVs by porcine transplants, a new approach, RNA interference (RNAi), was applied. Here, we show significant reduction of PERV expression by synthetic short interfering RNAs (siRNAs) corresponding to different parts of the viral genes
gag,
pol, and
env. The most inhibitory sequences were selected and expressed as short hairpin RNAs (shRNAs) by a polymerase III vector system leading to persistent suppression of PERV replication. Cells or organs from transgenic pigs producing such shRNAs should increase the safety of xenotransplantation.
The production of chemicals from renewable sources like lignocellulosic agricultural side products is widely seen as an important contribution to a sustainable future economy. Lignocellulosic biomass ...can be fractionated into its main components cellulose, hemicellulose, and lignin by Liquid Hot Water (LHW) or Ethanol Organosolv (EO) treatment. In order to optimize the biomass fractionation towards clean single components we investigated the sequential LHW and EO treatment of wheat straw. The release of carbohydrates and lignin was tracked over the treatment time. The experiments showed, that the treatment time should not exceed 30 min at 180 °C for each treatment. Furthermore, kinetic models for glucan and xylan fractionation during both treatments were created.
Human-tropic porcine endogenous retroviruses (PERV) such as PERV-A and PERV-B can infect human cells and are therefore a potential risk to recipients of xenotransplants. A similar risk is posed by ...recombinant viruses containing the receptor-binding site of PERV-A and large parts of the genome of the ecotropic PERV-C including its long terminal repeat (LTR). We describe here the unique organization of the PERV-C LTR and its changes during serial passage of recombinant virus in human cells. An increase in virus titer correlated with an increase in LTR length, caused by multiplication of 37-bp repeats containing nuclear factor Y binding sites. Luciferase dual reporter assays revealed a correlation between the number of repeats and the extent of expression. No alterations have been observed in the receptor-binding site, indicating that the increased titer is due to the changes in the LTR. These data indicate that recombinant PERVs generated during infection of human cells can adapt and subsequently replicate with greater efficiency.
To determine the mechanism of interaction between the HIV-1 gp41-specific broadly neutralizing monoclonal antibody (mAb) 2F5, its epitope in the membrane proximal external region and a domain located ...in the fusion peptide proximal region in the N-terminal region of gp41. Knowledge of these interactions would be useful for the design of antigens used to induce 2F5-like antibodies.
The binding and avidity of the mAb 2F5 were analyzed using enzyme-linked immunosorbent assays, epitope mapping and surface plasmon resonance analysis. Inhibition of virus neutralization by 2F5 was analyzed using peptides corresponding to the gp41 sequence.
Using transmembrane envelope proteins of gammaretroviruses, we had previously induced neutralizing antibodies that recognize two epitopes, one located in the N-terminal part of the transmembrane protein (designated E1) and the other in the C-terminal membrane proximal external region (E2). The E2 epitope corresponds to the mAb 2F5/4E10 epitope in the gp41 of HIV and we have now identified a corresponding E1 domain in gp41. Although 2F5 did not bind directly to E1, the presence of E1 peptides increased the binding of 2F5 to peptides carrying its epitope. Neutralization of HIV-1 by 2F5 was inhibited more effectively by both gp41-derived peptides E1 and E2 together than with the peptide E2 alone.
The interaction between the E1 and E2 domains of gp41 increased the efficacy of mAb 2F5 binding to its E2 epitope. Such an interaction may occur after gp41 folding into a six-helix bundle. Antigens containing both domains might be used to induce broadly neutralizing 2F5-like antibodies.
Popular views that female development entails a loss of voice and power in relationships have not been explored with Latina girls. In this study, data were collected from eight low-income Mexican ...American girls in middle and high school using surveys and open-ended interview questions. The findings show they view others as holding traditional expectations about how girls should behave, whereas they themselves engage in a more complex critique and performance of femininities in relationships with their family, peers, and teachers. The findings challenge assumptions that girls experience a linear loss of voice during adolescence, and suggest a distinction between personal power and power to help others. Finally, they show the importance of culture in understanding how girls negotiate gender roles. PUBLICATION ABSTRACT
ABSTRACT
Men’s health nights and men’s health sessions have proven to be remarkably successful in rural and some suburban regions of Victoria. In the rural regions, enough interest has been generated ...to run follow‐up health sessions on topics selected at the initial nights. Approximately 2000 men attended these events and 575 filled in questionnaires giving information such as age, occupation, health concerns and perceptions of health professionals. The results indicated that men’s health nights appeal to older men who are more likely to be professional or retired. These men saw cardiovascular disease, cancer and stress management as their main health concerns. The majority indicated that they would be interested in attending more men’s health sessions. The follow‐up sessions provide initial pathways by which men may address the issues of their own health. The data collected contributed to the development of the Men’s Awareness Network model for men’s health.
OBJECTIVE: Human endogenous retroviruses (HERVs) are suspected to be involved in oncogenesis and tumor progression. Transcripts of HERV-K have been detected in a multitude of human cancers as e.g., ...teratocarcinoma, mamma carcinoma or melanoma. The HERV-K splice variants env, rec, 1.5 kb transcript and Np9 have been suggested to be tumorigenic. To date, no reports about HERV-K expression are available concerning glioblastoma multiforme (GBM), the most common malignant brain tumor in adults, rapidly progressing and with a limited prognosis of 14.6 months in median. Therefore, we elucidated whether HERV-K transcripts could be detected in these tumors and serve as new molecular targets for treatment. METHODS: Five human GBM cell lines (U87, U138, U251, U343 and GaMG), a panel of patients' tissue samples (13 astrocytoma WHO° II, 17 GBM WHO° IV and 3 normal brain biopsies) and primary cell cultures of passages 2 and 6 were analyzed for the expression of HERV-K full length mRNA and env, rec and 1.5 kb transcripts by semiquantitative RT-PCR. RESULTS: Full length mRNA was strongly expressed in the GBM cell line U87, but weakly expressed in the GBM cell lines U138, U251, U343 and GaMG. The splice products could not be detected, despite a weak expression of env mRNA in U87 cells. Very few samples of the tissue panel showed weak expression of env mRNA, but none of the rec or 1.5 kb transcripts. Primary cells expressed the 1.5 kb transcript weakly in early passages, but lost HERV-K expression with extended culture time. CONCLUSIONS: Although expression of different splice variants of HERV-K have been reported to play a role in several malignancies and they were found in variable amounts in GBM cell lines, the lack of their expression in human tumor-biopsies confirms that HERV-K splice products do not play a role in human malignant gliomas and therefore, are not suitable as targets for new therapy regimen.
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