DENDRITIC CELLS IN THE PATHOGENESIS OF HIV-1 INFECTION

Dendritic antigen-presenting cells are responsible for the acquisition, processing, transport and presentation of antigen to the immune system. These cells may initiate immune responses, focus them in the lymphoid tissues and maintain the balance between cellular and humoral immunity.(1) They are the bone marrow-derived dendritic cells (DC) which interact preferentially with T cells, and follicular dendritic cells (FDC) of lymphoid germinal centres which stimulate B cells. DC play a pivotal role in the primary induction of immune responses in both health and disease.(2) Thus, involvement of DC has been described not only in the development of normal protective immunity, but also in initiation and perpetuation of autoimmunity, transplant rejection and tumour immunity. Modulation of T cell activity with some cytokines, vitamins or drugs may operate through effects on DC. By contrast, the FDC are concerned primarily with memory antibody responses. Evidence is now accumulating that both DC and FDC are targets for HIV-1. This article will discuss primarily the effects of HIV-1 on DC and their interactions with T lymphocytes.