Quantification of LCMV-Specific Antibodies

The LCMV Armstrong (LCMV^ARM) strain was kindly provided by R. Ahmed (Emory University, Atlanta, GA). Virus was grown in BHK-21 cells and titres (PFU) in the supernatant were determined as described before58 (link). For acute viral infections, mice were injected intraperitoneally with 2 × 10⁵ PFU of LCMV^ARM and analysed 10 days after infection18 (link)58 (link). LCMV-specific antibodies in the sera of mice were measured as described before18 (link)58 (link). Briefly, lysates of LCMV-infected BHK-21 cells were used as substrate and LCMV-specific IgG and IgM binding was detected in serial dilutions of serum using AP-conjugated goat-anti-mouse IgG or IgM antibodies (both Southern Biotech). Enzyme-linked immunosorbent assays (ELISAs) were developed with pNPP substrate (Thermo Scientific; cat. no. 37621) and absorbance was analysed at 405 nm using a SpectraMax M5 microplate reader (Molecular Devices).