Establishment of minimal positive-control conditions to ensure brain safety during rapid development of emergency vaccines

Baek, Hyekyung; Kim, Kwang Ho; Park, Min Young; Kim, Kyeongryun; Ko, Bokyeong; Seo, Hyung Seok; Kim, Byoung Soo; Hahn, Tae-Wook; Yi, Sun Shin

Evans blue (EB) assay for brain permeability: Two types of 7-week-old mice (C57BL/6 and ICR) and two LPS sources [Salmonella enterica, LPS(S) and Escherichia coli, LPS(E)] were used. Based on mouse type and LPS source, the C57BL/6 (B6) and ICR mice were assigned to 6 groups (n = 4): group 1, B6/PBS; group 2, B6/LPS(S); group 3, B6/LPS(E); group 4, ICR/PBS; group 5, ICR/LPS(S); and group 6, ICR/LPS(E). We performed the EB assay according to the method described by Jangula and Murphy [14] with a few modifications. Initially, we prepared LPS solutions using two different LPSs. The LPSs from S. enterica serotype enteritidis (L6011; Sigma, USA) and E. coli O55:B5 (L2880; Sigma) were separately dissolved in phosphate buffered saline (PBS; pH 7.4) to a concentration of 1 mg/4 mL.