Different classes of porcine endogenous retroviruses (PERVs), which have the potential to infect humans during xenotransplantation, have been isolated from the pig genome. Because vertebrate genomes may contain numerous endogenous retrovirus sequences, the pig genome was examined for additional endogenous retroviruses, resulting in the isolation of a novel, complete endogenous retrovirus genome, designated PERV-E. The gag, pol and env genes of PERV-E are closely related to those of human endogenous retrovirus (HERV) 4-1, which belongs to the HERV-E family. Results of studies to determine the presence and copy number of PERVs demonstrated that PERV-E and PERV-A/B-like proviruses were present in all genomes tested, but that PERV-C was not found in two of the species examined, including wild boar. Multiple copies of PERVs could be found in each pig genome. Among all of the pig genomes tested, the wild boar genome had the lowest copy number of all PERVs, suggesting that the number of integrations of complete endogenous retroviruses is increased by inbreeding. Xenotransplantation shows great promise for providing a virtually limitless supply of cells, tissues and organs for a variety of therapeutical procedures (Deacon et al., 1997 ; Bengtsson et al., 1998 ; Groth et al., 1994). The tissues and organs of domestic pigs are preferred for xenotransplantation because of their fundamental physiological compatibility with human organs compared to those of other mammals, such as the baboon (van der Kuyl & Goudsmit, 1999 ; Auchincloss & Sachs, 1998). Pigs can be bred and maintained under exogenous-pathogen-free conditions to

Purpose: Advanced prostate cancer represents a heterogeneous disease entity with differences in clinical behavior, response to therapy, and survival.We assessed whether we could distinguish poor from good prognosis patients at presentation in our clinic by means of quantifying circulating cell-free mitochondrial and genomic nucleic acids in plasma. Experimental Design: We collected plasma from 75 prostate cancer patients and from 14 subjects with benign disease. Nucleic acids were isolated, and mitochondrial DNA (mtDNA; 16S rRNA), mitochondrial RNA (mtRNA; cytochrome c oxidase subunit 1), and genomic DNA (U1A DNA) transcripts were quantified by real-time amplification. An association between cellfree nucleic acids and metastasis, prostate-specific antigen doubling time, and hemoglobin levels was determined. Multivariate Cox proportional hazard and survival estimation studies were done. Results: We show that elevated mtDNA and mtRNA levels are present in plasma of prostate cancer patients with a poor 2-year survival (P = 0.02 and 0.003, respectively). Cancer patients with high plasma mitochondrial nucleic acids, using a calculated optimal cutoff point, show a decreased survival compared with patients with low levels (35% versus 73% cumulative survival for mtDNA and 21% versus 73% for mtRNA). Multivariate analysis indicates that mtRNA is an independent predictor of 2-year survival. Conclusions: Quantification of plasma mitochondrial nucleic acids may be used to recognize patients with a poor prognosis. In advanced prostate cancer patients, mtRNA seemed the strongest predictor of overall survival and an independent prognostic factor for cancer-related death. Amplification of mitochondrial nucleic acids shows increased sensitivity and specificity over genomic DNA as diagnostic and prognostic marker in prostate cancer patients.

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Control of viremia in natural human immunodeficiency virus type 1 (HIV-1) infection in humans isassociated with a virus-specific T-cell response. However, still much is unknown with regard to the extent of CD8 ؉ cytotoxic T-lymphocyte (CTL) responses required to successfully control HIV-1 infection and to what extent CTL epitope escape can account for rises in viral load and ultimate progression to disease. In this study, we chose to monitor through full-length genome sequence of replication-competent biological clones the modifications that occurred within predicted CTL epitopes and to identify whether the alterations resulted in epitope escape from CTL recognition. From an extensive analysis of 59 biological HIV-1 clones generated over a period of 4 years from a single individual in whom the viral load was observed to rise, we identified the locations in the genome of five CD8 ؉ CTL epitopes. Fixed mutations were identified within the p17, gp120, gp41, Nef, and reverse transcriptase genes. Using a gamma interferon ELIspot assay, we identified for four of the five epitopes with fixed mutations a complete loss of T-cell reactivity against the wild-type epitope and a partial loss of reactivity against the mutant epitope. These results demonstrate the sequential accumulation of CTL escape in a patient during disease progression, indicating that multiple combinations of T-cell epitopes are required to control viremia.