Our group which was part of the Unit of Viral Oncology last year (2000) and which has been created as the new Unit of Epidemiology and Physiopathology of Oncogenic Viruses in 2001 has developed several projects in the following topics.
- Epidemiology of the Human Herpes Virus 8 (HHV8) and of the Human T Cell Leukemia Virus type 1 (HTLV-1) in endemic areas of French Guyana. We have demonstrated in a population based-study that HHV8 was mainly transmitted from mother to child and between siblings. The heterosexual transmission within couples seems very low. This was the first study regarding the intra-familial modes of transmission of this oncogenic virus in an endemic area. Such project on HHV8 is still ongoing in other highly endemic areas, especially in Cameroon, Central Africa. Other epidemiological studies regarding HTLV-1 and associated diseases are also in progress.
- Molecular epidemiology and genetic variability of HTLV-1/2 and related simian retroviruses (STLV-1/2). We have partially sequenced more than 30 new STLV-1 strains originating from Africa and South East Asia. Furthermore, the complete sequence (more than 9000 bp) of a novel, highly divergent, STLV has been obtained. Lastly a large epidemiological study on HTLV-2 infection is ongoing both on a clinical and molecular level in various ethnic populations of a rain forest area of South Cameroun.
- We have started a project in order to define the mechanism of resistance to apoptosis of the HTLV-1 infected cells as well as the mechanisms of action both in vivo and in vitro of some drugs used for the treatment of the HTLV-1 associated Adult T Cell Leukemia.
- Studies on the neuro-pathogenesis of HTLV-1 have also been performed. This includes mainly viro-molecular studies of the central nervous system and of muscular lesions in patients suffering of TSP/HAM (the neurological disease associated to HTLV-1) as well as studies on the in vitro passage of the blood brain barrier by HTLV-1.
- Genetic variability of HHV8 and related simian viruses. A study of 80 new HHV8 strains from patients suffering of Kaposi's sarcoma, primary effusion lymphoma or Castleman's disease and originating mainly from Africa has revealed the presence of several molecular variants and of two principal subtypes that are endemic in this continent. These works as well as those performed on HTLV-1/2 and STLV1/2 have permitted to gain new insights regarding the origin, evolution and modes of dissemination of these viruses and also often their primate hosts. Lastly, we have recently discovered and partially characterised several novel HHV8 related viruses in great apes and other monkeys from Central Africa.
- In vivo clonality of HHV8 associated diseases. Our preliminary results indicate for the first time the clonal origin (viral and cellular) of some of the tumour lesions of Kaposi's sarcoma strenghtening thus the potential oncogenic properties of HHV8 in vivo.
For most of these studies, the collaboration with numerous colleagues and friends of the Network of the Institut Pasteur and Instituts associés (especially Cameroon, Central African Republic and French Guyana) has been crucial.