LYMPHOCYTE TRAFFICKING AND HIV-INFECTION OF HUMAN LYMPHOID-TISSUE IN A ROTATING WALL VESSEL BIOREACTOR

The pathogenesis of HIV infection involves a complex interplay between both the infected and noninfected cells of human lymphoid tissue, the release of free viral particles, the de novo infection of cells, and the recirculatory trafficking of peripheral blood lymphocytes. To deve lop an ia vitro model for studying these various aspects of HIV pathog enesis we have utilized blocks of surgically excised human tonsils and a rotating wall vessel (RWV) cell culture system, Here we show that ( 1) fragments of the surgically excised human lymphoid tissue remain vi able and retain their gross cytoarchitecture for at least 3 weeks when cultured in the RWV system; (2) such lymphoid tissue gradually shows a loss of both T and B cells to the surrounding growth medium; however , this cellular migration is reversible as demonstrated by repopulatio n of the tissue by labeled cells from the growth medium; (3) this cell ular migration may be partially or completely inhibited by embedding t he blocks of lymphoid tissue in either a collagen or agarose gel matri x; these embedded tissue blocks retain most of the basic elements of a normal lymphoid cytoarchitecture; and (4) both embedded and nonembedd ed RWV-cultured blocks of human lymphoid tissue are capable of product ive infection by HIV-1 of at least three various strains of different tropism and phenotype, as shown by an increase in bath p24 antigen lev els and free virus in the culture medium, and by the demonstration of HIV-1 RNA-positive cells inside the tissue identified by in situ hybri dization, It is therefore reasonable to suggest that gel-embedded and nonembedded blocks of human lymphoid tissue, cocultured with a suspens ion of tonsillar lymphocytes in an RWV culture system, constitute a us eful model for simulating normal lymphocyte recirculatory traffic and provide a new tool for testing the various aspects of HIV pathogenesis .