Red neutravidin conjugated microspheres

ADCD was conducted as previously described^{58 (link)}. Briefly, NVX-CoV2373 Spike protein was biotinylated using EDC (Thermo Fisher) and Sulfo-NHS (Thermo Fisher), and then coupled to red Neutravidin-conjugated microspheres (Thermo Fisher) or directly coupled to Carboxylate-Modified microspheres (Thermo Fisher). Immune complexes were formed by incubating the bead + protein conjugates with diluted serum for 2 hours at 37°C, and then washed to remove unbound antibody. The immune complexes were then incubated with lyophilized guinea pig complement (Cedarlane) and diluted in gelatin veronal buffer with calcium and magnesium (Boston Bioproducts) for 30 minutes. C3 bound to immune complexes was detected by fluorescein-conjugated goat IgG fraction to guinea pig Complement Ce (MP Biomedicals). Flow cytometry was performed to identify the percentage of beads with bound C3. Flow cytometry was performed with an IQue (Intellicyt) and analysis was performed on IntelliCyt ForeCyt (v8.1).

ADCD was conducted as previously described^{58 (link)}. Briefly, NVX-CoV2373 Spike protein was biotinylated using EDC (Thermo Fisher) and Sulfo-NHS (Thermo Fisher), and then coupled to red Neutravidin-conjugated microspheres (Thermo Fisher) or directly coupled to Carboxylate-Modified microspheres (Thermo Fisher). Immune complexes were formed by incubating the bead+protein conjugates with diluted serum for 2 hours at 37°C, and then washed to remove unbound antibody. The immune complexes were then incubated with lyophilized guinea pig complement (Cedarlane) and diluted in gelatin veronal buffer with calcium and magnesium (Boston Bioproducts) for 30 minutes. C3 bound to immune complexes was detected by fluorescein-conjugated goat IgG fraction to guinea pig Complement Ce (MP Biomedicals). Flow cytometry was performed to identify the percentage of beads with bound C3. Flow cytometry was performed with an IQue (Intellicyt) and analysis was performed on IntelliCyt ForeCyt (v8.1).

ADCD was conducted as previously described [82 (link)]. Briefly, spike or RBD protein was biotinylated using EDC (Thermo Fisher Scientific) and EZ-link Sulfo-NHS-LC-LC (Thermo Fisher Scientific) and then coupled to red Neutravidin-conjugated microspheres (Thermo Fisher Scientific). Immune complexes were formed by incubating the bead+protein conjugates with diluted serum (ADCD 1:10 dilution) for 2 hours at 37°C and then washed to remove unbound antibody. The immune complexes were then incubated with lyophilized guinea pig complement (Cedarlane - Burlington, Ontario, Canada) and diluted in gelatin veronal buffer with calcium and magnesium (Boston BioProducts - Milford, Massachusetts, USA) for 30 minutes. C3 bound to immune complexes was detected by fluorescein-conjugated goat IgG fraction to guinea pig Complement C3 (MP Biomedicals - Irvine, California, USA). Flow cytometry was performed to identify the percentage of beads with bound C3 and a complement deposition score was calculated (% beads positive × median fluorescent intensity of positive beads). Flow cytometry was performed with an LSRII (BD) and analysis was performed using FlowJo V10.7.1.