Secretory leukocyte protease inhibitor inhibits infection of monocytes andlymphocytes with human immunodeficiency virus type 1 but does not interfere with transcytosis of cell-associated virus across tight epithelial barriers

In the present study, we demonstrate that recombinant human secretory leuko cyte protease inhibitor (rhSLPI) inhibits infection of lymphocyte- and mono cyte-derived tumor cell lines and peripheral blood lymphocytes with laborat ory-adapted Isolates and with the primary isolate, NDK, of free human immun odeficiency virus type 1 (HIV-1). In contrast, rhSLPI did not exhibit inhib itory activity toward transcytosis of cell-associated HIV-1 through a tight monolayer of endometrial epithelial cells. These observations indicate tha t the inhibitory effect of SLPI is restricted to free HIV-1 in corporal flu ids.