Consensus m2e peptide

Gold (III) chloride trihydrate (520918–5G), trisodium citrate dihydrate (S1804–500G), O-phenylenediamine (OPD) powder (P9029–50G), tween 20 (P1379–1L) and phosphate-citrate buffer tablet (P4809–50TAB) were purchased from Sigma-Aldrich (St. Louis, MO, USA). Consensus M2e peptide (acetylated-SLLTEVETPIRNEWGSRSNDSSDC-amidated, MW: 2736 Da) was chemically synthesized at 95% purity by AAPPTec (Louisville, KY, USA). Mouse CpG oligodeoxynucleotide (ODN) 1826 (5’-TCCATGACGTTCCTGACGTT-3’) and the ferret CpG ODN 2006 (5’-TCGTCGTTTTGTCGTTTTGTCGTT-3’), recognized by toll-like receptor 9 (TLR9), were synthesized by Integrated DNA Technologies (Coralville, IA, USA). Horseradish peroxidase (HRP)-conjugated goat anti-mouse secondary antibodies were bought from Southern Biotech (Birmingham, AL, USA). HRP-conjugated goat anti-ferret IgG was purchased from KPL Inc. (Gaithersburg, MD, USA). ELISA plate blocking buffer concentrate (80061) was obtained from Alpha Diagnostic International (San Antonio, TX, USA). 10X Tris/Boric acid/EDTA (1610733) was purchased from BioRad. 10X Phosphate buffered saline (PBS) (46013CM) was purchased from Fisher Scientific. Milli-Q water with a resistance of 18.2 MΩ cm was used in all the experiments.

Consensus M2e peptide (acetylated-SLLTEVETPIRNEWGSRSNDSSDC-amidated, MW: 2736 Da) was chemically synthesized by AAPPTec (Louisville, KY, USA). Underlined serines (S) are intentional substitutions of native cysteine to serine. CpG oligodeoxynucleotide (ODN) 1826 VacciGrade^™ (5′-TCCATGACGTTCCTGACGTT-3′) was purchased from InvivoGen (San Diego, CA, USA). Alexa-Fluor 488-labeledanti-mouse IgG antibody was obtained from Life Technologies (Carlsbad, CA, USA). All other secondary antibodies were purchased from Southern Biotech (Birmingham, AL, USA).