Elv covid19s1

The spike protein level on exosomes was measured by an ELISA using precoated ELISA plates (catalog number ELV-COVID19S1; RayBiotech), according to the manufacturer’s instructions, at RT. The nucleocapsid level on exosomes was measured by an ELISA using precoated ELISA plates (Legend Max SARS-CoV2 nucleocapsid protein ELISA kit, catalog number 448007; BioLegend), according to the manufacturer’s instructions, at RT. Briefly, samples and standards were loaded onto the precoated plate and incubated for 2 to 2.5 h at RT on a shaker (200 rpm). Plates were washed and incubated with a biotin-conjugated detection antibody for an hour at RT, followed by a 45-min incubation in a streptavidin solution. After washes, plates were developed using the TMB substrate. After a 30-min incubation, the reaction was stopped by the addition of a stop solution, and the absorbance at 450 nm was recorded using a BioTek Gen5 plate reader (Agilent). For nucleocapsid, after a 10-min incubation with the TMB substrate, the absorbance was recorded at 450 nm and 570 nm. For analysis, the absorbance at 570 nm can be subtracted from the absorbance at 450 nm, and the OD can be used to build a standard curve.

The spike protein level on exosomes was measured by an ELISA using precoated ELISA plates (catalog number ELV-COVID19S1; RayBiotech), according to the manufacturer’s instructions, at RT. The nucleocapsid level on exosomes was measured by an ELISA using precoated ELISA plates (Legend Max SARS-CoV2 nucleocapsid protein ELISA kit, catalog number 448007; BioLegend), according to the manufacturer’s instructions, at RT. Briefly, samples and standards were loaded onto the precoated plate and incubated for 2 to 2.5 h at RT on a shaker (200 rpm). Plates were washed and incubated with a biotin-conjugated detection antibody for an hour at RT, followed by a 45-min incubation in a streptavidin solution. After washes, plates were developed using the TMB substrate. After a 30-min incubation, the reaction was stopped by the addition of a stop solution, and the absorbance at 450 nm was recorded using a BioTek Gen5 plate reader (Agilent). For nucleocapsid, after a 10-min incubation with the TMB substrate, the absorbance was recorded at 450 nm and 570 nm. For analysis, the absorbance at 570 nm can be subtracted from the absorbance at 450 nm, and the OD can be used to build a standard curve.

Spike protein level on exosomes was measured by ELISA using precoated ELISA plates (ELV-COVID19S1, RayBiotech) according to the manufacturer’s instructions, at RT. Briefly, samples were lysed in RIPA buffer for 30 min on ice with vortexing every 10 min. After, samples and standards were loaded onto the precoated plate, and incubated on a shaker. Plates were washed and incubated with biotin-conjugated detection antibody for an hour at RT, followed by 45 min incubation in streptavidin solution. After washes, plates were developed for 30 min using TMB substrate. The reaction was stopped by adding STOP solution and the absorbance at 450 nm using a BioTeck Gen5 plate reader (Agilent).