SECRETORY IMMUNOGLOBULIN-A BLOCKS HYPOXIA-AUGMENTED BACTERIAL PASSAGEACROSS MADIN-DARBY CANINE KIDNEY-CELL MONOLAYERS

Objective: To study the relative impact of previous hypoxic exposure a nd the addition of secretory immunglobulin A (IgA) on bacterial transl ocation. Design: In vitro randomized experimental study. Materials and Methods: Transfected Madin-Darby canine kidney epithelial cells were grown as monolayers in a two-chamber tissue culture system. Stationary growth phase Escherichia coil M14 were inoculated in the apical chamb er with medium or medium containing polymeric secretory IgA. Tissue cu lture dishes were then placed in a 21 or 5% O-2 incubator environment for 90 minutes followed by a 21% O-2 environment. Medium from the basa l compartment was then obtained at timed intervals for bacterial cultu re. Measurement and Main Results: Bacterial translocation increased wi th time in co-culture. previous hypoxic exposure augmented translocati on across the monolayers. The addition of IgA blocked translocation un der both normoxic and hypoxic conditions. Conclusions: Secretory IgA i s important in mucosal defense under both normal and shock conditions.