Antibody-mediated enhancement aggravates chikungunya virus infection and disease severity

Lum, Fok-Moon; Couderc, Thérèse; Chia, Bing-Shao; Ong, Ruo-Yan; Her, Zhisheng; Chow, Angela; Leo, Yee-Sin; Kam, Yiu-Wing; Rénia, Laurent; Lecuit, Marc; Ng, Lisa F. P.

Excised joint footpads were shredded and digested in digestion medium containing dispase (2 U/ml; Invitrogen), collagenase IV (20 mg/ml; Sigma-Aldrich), and DNase I mix (50 mg/ml; Roche Applied Science) in complete RPMI medium for 3 h at 37 °C. Cell debris and skin tissues were removed by passing through 40 μm cell strainer (BD Falcon) followed by RBC lysis (R&D system). Cells were further purified by spinning down in 35% v/v Percoll (Sigma) solution in RPMI prior to staining. The popliteal lymph node (pLN), located at the area to the back of the mice knee joint, was delicately retrieved and briefly digested in 1 ml of digestion medium containing dispase (2 U/ml), collagenase IV (20 mg/ml), and DNase I mix (50 mg/ml) in complete RPMI medium for 30 min at 37 °C. Disintegration of pLN was encouraged by gentle pipetting before passing contents through a 70 μm nylon mesh cloth (Sefar). RBCs were further lyzed with RBC lysis buffer (R&D system) prior to further staining procedures.