Al control. F-actin content was ascertained by staining with Alexa-488 phalloidin after 5 h and “ control” determined versus control cells in media only. Each toxin concentration represents mean +/2 standard deviation of duplicate wells from three separate experiments.Binding of Iota-family B Components to Purified CD44 in SolutionSolution-based experiments were subsequently done using purified CD44 with Ib and other B components from C. spiroforme (CSTb), C. difficile (CDTb), and C. 
botulinum (C2IIa). B component (10 mg) was added to CD44-IgG or CD44-GST (10 mg) in 20 mM Hepes buffer, pH 7.5 containing 150 mM NaCl for 60 min at room temperature (50 ml total volume). Protein A-agarose (used with CD44-IgG construct) or glutathione-sepharose (used with CD44-GST construct) beads (Sigma) were then added for 5 min at room temperature, gently centrifuged, and washed with buffer. SDS-PAGE sample buffer containing reducing agent was added to the beads, the mixture heated, and protein separated from beads by centrifugation. Supernatant proteins were then separated by 10 SDS-PAGE, transferred onto nitrocellulose, and B components detected with either rabbit anti-Ib or -C2IIa sera (1:1,000 dilution). Protein A-peroxidase get Tubastatin A conjugate (Bio-Rad) was used at a 1:3000 dilution, and following washes, specific B component bands were visualized with SuperSignal West Pico 374913-63-0 web chemiluminescent substrate (Thermo Scientific).Western Blot and Co-precipitation Analysis of LSR on CellsDetection of LSR on RPM and Vero cells was 1662274 done by Western blot using rabbit anti-LSR sera. Initial co-precipitation experiments were done with RPM (CD44+ and CD442), as well as Vero, cells. Briefly, cells were grown to confluence in 10 cm dishes. Cells were washed with DMEM and incubated with or without Ib (1027 M) at 37uC for 30 min with medium containing 1 bovine serum albumin. Following PBS washes, cells were subsequently lysed with PBS containing Tris (50 mM, pH 8), NaCl (150 mM), Triton X-100 (0.5 ), as well as protease and phosphatase inhibitors. Antibody against 23727046 CD44 (10 mg) was added to cell lysate (1 ml) at room temperature and rotated for 2 h, followed by protein A beads for 30 min. Beads were centrifuged, washed in PBS, and bound proteins prepared for SDS-PAGE. Following electrophoresis, proteins were transferred onto nitrocellulose and incubated with rabbit anti-LSR sera. There were subsequent serial washings, addition of protein A-horseradish peroxidase conjugate, and then development by ECL.Mouse LethalityHomozygous CD44 knockout and wild-type control mice (C57BL/6J parental strain; ,20 g males) were purchased from Jackson Laboratories [60]. Two separate experiments were done using an intraperitoneal injection of each mouse with sterile PBS containing Ia (0.5 mg) and Ib (0.75 mg). Mice were monitored for morbidity and mortality every 4 h post injection, up to 48 h.Author ContributionsConceived and designed the experiments: DJW GR RJC NS MRP BGS HB. Performed the experiments: DJW GR LS RJC SP MG NS MRP 
BGS HB. Analyzed the data: DJW GR PH JB TDV RJC TDW GTVN MRP BGS HB. Contributed reagents/materials/analysis tools: DJW GR PH JB TDV RJC TDW GTVN MRP BGS HB. Wrote the paper: DJW GR JB RJC MRP BGS HB.
It has been shown for some time that cytomegalovirus (CMV) and herpes simplex virus (HSV) can cause severe disease in immunocompromised patients, either via reactivation of a latent viral infection (the most frequent cause) or via the acquisition of a primary viral infection.Al control. F-actin content was ascertained by staining with Alexa-488 phalloidin after 5 h and “ control” determined versus control cells in media only. Each toxin concentration represents mean +/2 standard deviation of duplicate wells from three separate experiments.Binding of Iota-family B Components to Purified CD44 in SolutionSolution-based experiments were subsequently done using purified CD44 with Ib and other B components from C. spiroforme (CSTb), C. difficile (CDTb), and C. botulinum (C2IIa). B component (10 mg) was added to CD44-IgG or CD44-GST (10 mg) in 20 mM Hepes buffer, pH 7.5 containing 150 mM NaCl for 60 min at room temperature (50 ml total volume). Protein A-agarose (used with CD44-IgG construct) or glutathione-sepharose (used with CD44-GST construct) beads (Sigma) were then added for 5 min at room temperature, gently centrifuged, and washed with buffer. SDS-PAGE sample buffer containing reducing agent was added to the beads, the mixture heated, and protein separated from beads by centrifugation. Supernatant proteins were then separated by 10 SDS-PAGE, transferred onto nitrocellulose, and B components detected with either rabbit anti-Ib or -C2IIa sera (1:1,000 dilution). Protein A-peroxidase conjugate (Bio-Rad) was used at a 1:3000 dilution, and following washes, specific B component bands were visualized with SuperSignal West Pico chemiluminescent substrate (Thermo Scientific).Western Blot and Co-precipitation Analysis of LSR on CellsDetection of LSR on RPM and Vero cells was 1662274 done by Western blot using rabbit anti-LSR sera. Initial co-precipitation experiments were done with RPM (CD44+ and CD442), as well as Vero, cells. Briefly, cells were grown to confluence in 10 cm dishes. Cells were washed with DMEM and incubated with or without Ib (1027 M) at 37uC for 30 min with medium containing 1 bovine serum albumin. Following PBS washes, cells were subsequently lysed with PBS containing Tris (50 mM, pH 8), NaCl (150 mM), Triton X-100 (0.5 ), as well as protease and phosphatase inhibitors. Antibody against 23727046 CD44 (10 mg) was added to cell lysate (1 ml) at room temperature and rotated for 2 h, followed by protein A beads for 30 min. Beads were centrifuged, washed in PBS, and bound proteins prepared for SDS-PAGE. Following electrophoresis, proteins were transferred onto nitrocellulose and incubated with rabbit anti-LSR sera. There were subsequent serial washings, addition of protein A-horseradish peroxidase conjugate, and then development by ECL.Mouse LethalityHomozygous CD44 knockout and wild-type control mice (C57BL/6J parental strain; ,20 g males) were purchased from Jackson Laboratories [60]. Two separate experiments were done using an intraperitoneal injection of each mouse with sterile PBS containing Ia (0.5 mg) and Ib (0.75 mg). Mice were monitored for morbidity and mortality every 4 h post injection, up to 48 h.Author ContributionsConceived and designed the experiments: DJW GR RJC NS MRP BGS HB. Performed the experiments: DJW GR LS RJC SP MG NS MRP BGS HB. Analyzed the data: DJW GR PH JB TDV RJC TDW GTVN MRP BGS HB. Contributed reagents/materials/analysis tools: DJW GR PH JB TDV RJC TDW GTVN MRP BGS HB. Wrote the paper: DJW GR JB RJC MRP BGS HB.
It has been shown for some time that cytomegalovirus (CMV) and herpes simplex virus (HSV) can cause severe disease in immunocompromised patients, either via reactivation of a latent viral infection (the most frequent cause) or via the acquisition of a primary viral infection.