Search

To investigate the relationship between the fusogenic properties of HTLV-II and the processing of the envelope precursor glycoprotein gp63, recombinant cowpox virus expressing this protein was used to infect a range of cell lines derived from different species. Syncytium formation and gp63 processing were observed in all cells with the exception of LoVo cells, which are known to have a dysfunctional form of the endoprotease, furin. Furin has been shown to be necessary for the processing of a number of viral envelope glycoproteins, and gp63 contains a consensus sequence 305Arg-Arg-Arg-Arg, which is a furin substrate motif. Pulse–chase studies demonstrated gp63 processing in Vero but not in LoVo cells. In addition it could be shown that expression of recombinant furin restored the processing of gp63 to gp46 in LoVo cells, and this resulted in syncytium formation. Our findings suggest that furin plays a pivotal role in cleavage of the HTLV-II envelope gp63, which in turn is a prerequisite for the fusogenic properties of the virus.

Serological and molecular analyses of a cohort of HIV-1-infected intravenous drug abusers (IVDAs) (n = 103) in Dublin, Ireland have demonstrated that 15 of 103 (14.6%) were infected with HTLV-II, which is the highest infection rate yet recorded for any European country. Restriction fragment length polymorphism (RFLP) analysis of the env region of the provirus demonstrated that the infection involved only the HTLV-IIa subtype; the HTLV-IIb subtype was not detected. Phylogenetic analysis of the nucleotide sequences of the long terminal repeat (LTR) confirmed infection with the HTLV-IIa subtype, and demonstrated that the viruses clustered closely with HTLV-IIa isolates from North American IVDAs. Previous observations that IVDAs in southern Europe, specifically Spain and Italy, appear to be infected predominantly with the HTLV-IIb subtype, along with the present report and evidence that IVDAs in Sweden are infected with the HTLV-IIa subtype, suggest different origins of HTLV-II infection in Europe.

Partial 16S nucleotide sequences of Chlamydia psittaciisolates S26/3 (abortion), P94/1 (pigeon) and Chlamydia pecorumisolates W73 (enteric) and E58 (encephalomyelitis) were determined. Analysis of these data indicates very high levels of interspecies sequence conservation, with C. psittacibeing more closely related to C. pecorumthan to C. pneumoniaeor C. trachomatis. Restriction enzyme analysis of nucleotide sequences indicated that BslI can be used to clearly distinguish C. psittaciand C. pecorumisolates. Psittacine and non‐psittacine (pigeon) avian isolates of C. psittaciwere distinguished using MaeI.

Partial 16S nucleotide sequences of Chlamydia psittaci isolates S26/3 (abortion), P94/1 (pigeon) and Chlamydia pecorum isolates W73 (enteric) and E58 (encephalomyelitis) were determined. Analysis of these data indicates very high levels of interspecies sequence conservation, with C. psittaci being more closely related to C. pecorum than to C. pneumoniae or C. trachomatis. Restriction enzyme analysis of nucleotide sequences indicated that BslI can be used to clearly distinguish C. psittaci and C. pecorum isolates. Psittacine and non-psittacine (pigeon) avian isolates of C. psittaci were distinguished using MaeI.