Fig. 2

Schematic model of HTLV-1 transmission to new individuals during primary infection and after exposure to donor infected T-cells or macrophages (Takeuchi [32], de Revel [55]). Infected T-cells from infected donors are colored in dark blue. Viral expression is depicted by viral particles at the surface of infected T-cells in biofilm (represented as a cloud) or in infected DC. Viral infection is depicted as DNA present in nucleus. a After contact of donors infected cells with recipient DC present in the genital track and intestine mucosa, recipient mucosal dendritic cells could be at the forefront of the infection and being the first to be de novo infected probably by viral biofilm. b After transfer of donor infected cells through blood, donor infected T-cells might transit to lymph node, in which they could transfer HTLV-1 to naïve resident DC. c In lymph nodes, productively infected DC could contact naïve T-cells and concomitantly transfer HTLV-1 to T-cells through viral synapse. d Recipient infected DC might then migrate to bone marrow in which they could infect HSC. Bone marrow hematopoiesis will results in HSC differentiation and viral dissemination in multiple cell type that may have not directly contacted newly produced HTLV-1 particles. Inherited viral DNA would increase PVL and may disseminate HTLV-1 to CNS