Epstein-Barr virus strain characterisation in South African patients with nasopharyngeal carcinomas.

UNLABELLED: Epstein-Barr virus (EBV) has been implicated in various diseases, among others, nasopharyngeal carcinoma (NPC). In this study we investigated the frequency and subtype distribution of EBV in 39 NPCs. The presence of EBV was detected by using a nested PCR to amplify the Bam Hl W-fragment of the genome. Two regions were targeted for subtype analysis, namely the EBNA-2A and EBER regions. PCR was used to amplify these regions, and the EBER region was sequenced to detect subtype specificity. The results showed that EBV could be detected in 82% (31/38) of the tumours. In 15 of these, EBNA subtypes could be identified of which 14 were subtype A and one tumour had both subtypes A and B present. The EBER region was amplified in 21 samples. The majority of cases (18/21) demonstrated a mutation profile which consisted of 5 type B and one type A mutations. The consensus type is therefore type B. IN CONCLUSION: a strong association was found between EBV and NPCs in our group of patients and their "consensus" genotype was A/B based on the two genome areas investigated.

Sequence variation and subtyping of human and simian T-cell lymphotropic virus type I strains from South Africa.

We report on the subtyping of South African primate T-cell lymphotropic virus type I (PTLV-I) strains by investigating the LTR region using sequence analysis and restriction fragment length polymorphism (RFLP) techniques. DNA from either uncultured peripheral blood mononuclear cells (PBMCs); cultured PBMC or cell lines of eight human T-cell lymphotropic virus type I (HTLV-I); and two simian T-cell lymphotropic virus type I (STLV-I) strains (Cercopithecus aethiops pygerythrus) were amplified by polymerase chain reaction (PCR), cloned, and sequenced. The samples originated from different geographical regions in South Africa. Phylogenetic relationships were estimated using the neighbor-joining method. The South African HTLV-I strains were of Cosmopolitan origin and similar to each other. RFLP analysis confirmed this subtyping. A divergence of 0.3 to 1.6% between the Cosmopolitan strains was observed, while the divergence between the HTLV-I and STLV-I strains ranged from 6.3 to 7%. The STLV-I strains were closely related to that of a chimpanzee, providing evidence of interspecies transmission.

Isolation of a new human herpesvirus producing a lytic infection of helper (CD4) T-lymphocytes in peripheral blood lymphocyte cultures--another cause of acquired immunodeficiency?

A new human helper (CD4) T-lymphotropic herpesvirus (HTLHV) was first isolated in February 1985 from the cultured peripheral blood lymphocytes (PBL) of a patient with the acquired immunodeficiency syndrome, and subsequently from the PBL of 1 patient with hairy cell leukaemia and 2 patients with lymphoproliferative disease associated with human T-lymphotropic virus type I infection. The viruses could be serially subcultured in umbilical cord PBL cultures in which they infected helper (CD4) T-lymphocytes producing multinucleate giant cells with intranuclear inclusions followed by cell lysis. Electron microscopy of infected cultures revealed that the isolates were herpesviruses. Specific DNA probing showed that the 4 isolates were related to one another but were distinct from cytomegalovirus, Epstein-Barr virus, Herpesvirus hominis types 1 and 2, and varicella-zoster virus. HTLHV lyses the same target cell as human immunodeficiency virus in PBL cultures suggesting that it may have a similar potential to cause acquired immune deficiency. The development of an unequivocally diagnostic serological test is a priority, so that the epidemiology and pathogenesis of HTLHV infection can be studied.

Simian immunodeficiency viruses (SIVs) from eastern and southern Africa: detection of a SIVagm variant from a chacma baboon.

Simian immunodeficiency viruses (SIVs) have been shown to infect many Old World African primate species. Thus far, no work has been published on southern African primates. In this study we investigated the genetic diversity between SIV strains from Kenyan and South African vervets (Cercopithecus aethiops pygerythrus). We amplified and sequenced a 1113 bp region of the env gene. Phylogenetic analysis of these sequences showed that all strains clustered with members of the vervet subgroup of SIVagm. The SIVs from South African vervets differed by 7% from each other and by 8-14% from the Kenyan SIV strains, while the Kenyan SIV strains differed by 10-21% from SIVagm of other east African vervets. We also isolated and sequenced, for the first time, a SIV strain from a healthy chacma baboon (Papio ursinus), caught in South Africa. Phylogenetic analysis of the env region showed the virus to be closely related to the South African vervet SIV strains, while analysis of its pol region confirmed the virus to be a SIVagm variant.