Human Immunodeficiency Virus Type 2

In virology, Human Immunodeficiency Virus Type 2 (HIV-2) is an "HIV species related to HIV-1 but carrying different antigenic components and with differing nucleic acid composition. It shares serologic reactivity and sequence homology with the simian Lentivirus Simian Immunodeficiency Virus and infects only T4-lymphocytes expressing the CD4 phenotypic marker."