title: Comparison of replication-competent molecular clones of porcine endogenous retrovirus class A and class B derived from pig and human cells.
abstract: Vertically transmitted endogenous retroviruses pose an infectious risk in the course of pig-to-human transplantation of cells, tissues, and organs. Two classes of polytropic type C porcine endogenous retroviruses (PERV) which are infectious for human cells in vitro are known. Recently, we described the cloning and characterization of replication-competent PERV-B sequences from productively infected human cells (F. Czauderna, N. Fischer, K. Boller, R. Kurth, and R. R. Tönjes, J. Virol. 74:4028-4038, 2000). Here, we report the isolation of infectious molecular PERV-A and PERV-B clones from pig cells and compare these proviruses with clones derived from infected human 293 cells. In addition to clone PERV-A(42) derived from 293 cells, four "native" full-length proviral PERV sequences derived from a genomic library of the porcine cell line PK15 were isolated. Three identical class A clones, designated PK15-PERV-A(42), PK15-PERV-A(45), and PK15-PERV-A(58), and one class B clone, PK15-PERV-B(213), were characterized. PK15-PERV-B(213) is highly homologous but distinct from the previously described clone PERV-B(43). PK15-PERV-A(58) demonstrates close homology to PERV-A(42) in env and to PERV-C in long terminal repeat, gag, and pro/pol sequences. All three PERV clones described here were replication competent upon infection of susceptible cell lines. The findings suggest that the pig genome harbors a limited number of infectious PERV-A and -B sequences.
authors.affiliation: Paul-Ehrlich-Institut, D-63225 Langen, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Krach
authors.forename: N
authors.initials: N
authors.lastname: Fischer
authors.forename: F
authors.initials: F
authors.lastname: Czauderna
authors.forename: R R
authors.initials: RR
authors.lastname: Tönjes
mesh_terms: D000818:Animals; D030121:Betaretrovirus / Q000235:genetics* / Q000502:physiology; D002460:Cell Line; D003001:Cloning, Molecular; D020077:Endogenous Retroviruses / Q000235:genetics* / Q000502:physiology; D006801:Humans; D008969:Molecular Sequence Data; D011533:Proviruses / Q000235:genetics; D012192:Retroviridae Infections / Q000821:virology*; D017422:Sequence Analysis, DNA; D013552:Swine; D014779:Virus Replication / Q000502:physiology*