Detection, cloning, molecular characterization and phylogenic analyses of a new primate T-Cell lymphotropic virus type I in olive baboon

Infection with Human T-cell Lymphotropic Virus Type I (HTLV-I) is a global health problem, affecting 10 to 20 million people around the world, including north-east of Iran. It has been recognized to be the etiologic agent of adult T-cell Leukemia and HTLV-I-associated Myelopathy. In both cases, the HTLV-I transactivator protein (Tax), plays crucial role. Monkeys are suitable host for a related virus called STLV, which together with HTLV are called Primate T-cell Lymphotropic Viruses (PTLVs). Primates are the only known hosts, in addition to human, to be able to develop malignant changes in the natural course of infection with PTLV-I and therefore, could be a valuable animal model for studies on this virus. In the present study, we report PCR-based detection and cloning of 1.8 kb pX region of a new PTLV in olive baboon (Papio anubis). Sequence alignments and phylogenic studies on nucleotide sequence of this region and amino acids of conceptually translated Tax protein showed that monkeys are infected with a PTLV much closer to HTLV-I sub-types a and b, rather than STLV-I. Moreover, analyses of its Tax protein suggest that it might have the same function as HTLV-I Tax proteins. Results of our study indicate the possibility of exploiting these baboons as an animal model of choice for evaluating a tax-based DNA vaccine to decrease the viral load of HTLV-I in carriers , in order to prevent the outcomes, as well as they may be utilized for other HTLV-I physiopathologic or therapeutic studies.