Fig. 2.

SGMS1^GT cells are defective in influenza viral particles production. (A) Equal numbers of KBM7 and SGMS1^GT cells were infected with influenza virus (A/WSN/33) at an MOI of 0.1. At 24 h after infection, cells were pulse-labeled with [³⁵S]-methionine/cysteine for 30 min and total cell lysates were analyzed by SDS/PAGE and autoradiography. (B) Cells were infected as described in A, and viral titers from the supernatant were measured by a fluorescent focus assay on MDCK cells. (C) Cells were incubated at different MOIs with Alexa 647-labeled influenza virus for 30 min on ice, followed by cytofluorimetry. (D) Flow cytometry of Alexa 647-positive cells upon exposure of KBM7, SGMS1^GT, and SLC25A2^GT with CTx-Alexa647 for 15 min on ice. SLC25A2^GT cells are defective in GM1 biosynthesis and hence CTx is unable to bind to these cells. (E) Confocal images of KBM7 and SGMS1^GT cells incubated with Alexa 647-labeled influenza virus and Alexa 488-CTx for 30 min on ice. FFU, focus-forming unit.