Cell culture and ZIKV infection

ZIKV (Puerto Rico strain PRVABC59; ATCC #VR-1843) was propagated in C6/36 cells (ATCC #CRL-1660) in minimum essential medium (MEM) supplemented with 2% fetal calf serum (FCS; Life Technologies; Gaithersburg, MD). An unverified immortalized B cell line (Priess; Millipore Sigma #86052111) homozygous for HLA-A*02:01 and HLA-DRB1*04:01 was used for this study. The complete HLA profile for Priess cells (as reported by the European Collection of Authenticated Cell Cultures) is HLA-A*02:01, HLA-B*15, HLA-DRB1*04:01, HLA-DRB4*01:01, HLA-DQA1*03, HLA-DQB1*03, HLA-DPA1*01:03, HLA-DPB1*03:01, HLA-DPB1*04:01. Priess cells (~ 4 x 10⁸) were infected with ZIKV at a multiplicity of infection (MOI) of 0.5 for 2 hours and subsequently maintained for 5 days in MEM supplemented with 2% FCS. Negative control cell cultures consisted of Priess cells mock-infected with virus-free PBS.