magnetic microbeads (Miltenyi Biotech). CD14-depleted fractions were stained on
ice for 15–20 min with the following fluorochrome-labeled mouse
monoclonal antibodies: CD8-PE–Cy5 (clone B9.11; cat. no. A07758),
CD14-PE–Cy5 (clone RMO52; cat. no. A07765), CD16-PE–Cy5 (clone
3G8; cat. no. A07767), CD45RA-FITC (clone ALB11; cat. no. A07786) from Beckman
Coulter, CD19-PE–Cy7 (clone SJ25C1; cat. no. 341113), CD25–PE
(clone M-A251; cat. no. 555432) from BD Biosciences, CD4–PE–Texas
Red (clone S3.5; cat. no. MHCD0417) from ThermoFisher Scientific,
CCR7–BV421 (clone G043H7; cat. no. 353208) from BioLegend, Alexa Fluor
647-conjugated goat anti-human IgG (cat. no. 109-606-170) from Jackson
ImmunoResearch. IgG+ memory B cells were sorted from CD19+B cells to over 98% purity on a FACSAria III (BD). Memory CD4+ T
cells were sorted to over 98% purity after exclusion of naïve
CD4+ T cells (CD45RA+CCR7+) and
CD8+, CD14+, CD16+, CD19+,
CD25bright cells.