Immunoblotting detection of BoHV-1 (A), PRV (B), and HSV-1 gB (C) in cell lysates (cl) of constructed cell lines or SEC-isolated EVs. (+): gB-expressing cells; (−): MJSpuro, MDBKpuro, SK6puro, or untransduced Jurkat cells (Ø) were used as negative controls. Virus-infected cell lysates (cl) were analyzed as positive controls; in the case of BoHV-1, gB was immunoprecipitated (IP) with H2 antibody before immunoblotting with anti-BoHV-1 serum. Size markers are in kilodaltons. gBa: uncleaved BoHV-1 and PRV gB precursor; gBb: cleaved N-terminal gB subunit; gBc: cleaved C-terminal gB subunit.