HIV-1 and HTLV-1 Transmission Modes: Mechanisms and Importance for Virus Spread

Viruses. 2022 Jan 14;14(1):152. doi: 10.3390/v14010152.


So far, only two retroviruses, human immunodeficiency virus (HIV) (type 1 and 2) and human T-cell lymphotropic virus type 1 (HTLV-1), have been recognized as pathogenic for humans. Both viruses mainly infect CD4+ T lymphocytes. HIV replication induces the apoptosis of CD4 lymphocytes, leading to the development of acquired immunodeficiency syndrome (AIDS). After a long clinical latency period, HTLV-1 can transform lymphocytes, with subsequent uncontrolled proliferation and the manifestation of a disease called adult T-cell leukemia (ATLL). Certain infected patients develop neurological autoimmune disorder called HTLV-1-associated myelopathy, also known as tropical spastic paraparesis (HAM/TSP). Both viruses are transmitted between individuals via blood transfusion, tissue/organ transplantation, breastfeeding, and sexual intercourse. Within the host, these viruses can spread utilizing either cell-free or cell-to-cell modes of transmission. In this review, we discuss the mechanisms and importance of each mode of transmission for the biology of HIV-1 and HTLV-1.

Keywords: HIV-1; HTLV-1; cell-to-cell transmission; cytonemes; filopodia; replication-dependent vectors; virological synapse.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • CD4-Positive T-Lymphocytes / immunology
  • CD4-Positive T-Lymphocytes / virology*
  • HIV Infections / transmission*
  • HIV-1 / pathogenicity*
  • HTLV-I Infections / complications
  • HTLV-I Infections / transmission*
  • Human T-lymphotropic virus 1 / pathogenicity*
  • Humans
  • Leukemia-Lymphoma, Adult T-Cell / virology*
  • Mice