QR uptake is prevented by anti-ANX antibody.

Groups of six polyps were equilibrated in SolHy pH 4 in presence of the indicated doses of the affinity purified antibodies (rabbit anti-annexin XII, rabbit anti human endocytic accessory protein AP180) or of bovin serum albumine (BSA). 1 h later QRs were added to the polyps and after at least 4 h of incubation the presence of internalization was monitored under a fluorescence microscope. As BSA is used for IgG stabilization, in each column is reported the amount of antibody used, together with the BSA co-administrated (in brackets). An additional set of experiment was performed by supplying pure BSA at different concentrations, to rule out its aspecific role in the uptake process. Inhibition of QR uptake, indicated by the plus sign (+) was observed in presence of anti-ANX, while was not prevented by either aspefic antibody nor BSA even at higher doses [indicated by the sign minus (−)].