The mice were maintained in a patho gen free environment. Cell culture T84 cells were purchased from ATCC. Passages 33 38 were used in the study. new The cells were cultured in DMEM supplemented with 10% fetal bovine serum, 2 mM L glutamine, 100 U ml penicillin and 0. 1 mg ml streptomycin. Cells were seeded onto the inserts of Transwells at 106 cells ml. The medium was changed daily. Recording transepithelial electric resistance The TER was measured with an Ohmmeter following our established procedures. Assessment of T84 monolayer permeability After the confluence of the T84 monolayers, the OVA was added to the Transwell ap ical chambers at a concentration of 10 ug ml. Samples were collected from the basal chambers 48 h later. The contents of OVA in the samples were determined by ELISA with a commercial reagent kit following the manufacturers instructions.

Quantitative real time RT PCR Total RNA was extracted from T84 cells with the TRIzol reagents. The cDNA was synthesized with a reverse tran scription kit. qPCR was performed in a real time PCR sys tem with the SYBR Green Super Mix. The results were calculated with the 2 Ct method. The primers using in this study in clude, Alix, forward, aaggaacgttggcaaaggac, reverse, gaagg gatggcagcattcag. B actin, forward, cgcaaagacctgtatgccaa, reverse, cacacagagtacttgcgctc. Western blotting Total proteins were extracted from T84 cells, fractioned by SDS PAGE and transferred onto a nitrocellulose membrane. The membrane was blocked by 1% bovine serum albumin and incubated with the primary antibodies for 1 h at room temperature, and followed by incubation with the secondary antibodies for 1 h.

Washing with TBST was performed after each incubation. The immune blots on the mem brane were developed with ECL. The results were recorded with x ray films. RNA interference T84 cells were treated with RNAi to knock down the genes of Alix or Toll like receptor 2 with commercial re agent kits following the manufacturers instructions. The ef fect of gene knockdown was checked by Western blotting. The results of gene silence reached its peaked value on day 4 after the transduction and lasted at least 4 weeks. The data are presented in Figures 1 and 2 respectively Over expression of the Alix gene T84 cells were washed with phosphate buffered saline, the genomic DNA was extracted from T84 cells. The Alix gene was amplified by PCR.

The products of PCR were sequenced first and confirmed, and cloned into the pTZ57R T vector and transformed into E. coli. The vectors of Alix gene were subcloned into the pcDNA3 plasmid, and transformed into competent E. coli by the heat shock method. The plasmid was then purified using a plasmid extraction kit according to the manufacturers in structions. The presence of the Alix gene was confirmed by sequencing. T84 cells were transfected with the con structed plasmids using a transfection Brefeldin_A kit according to the manufacturers instructions.