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.

extracted from 50 ml of donors' blood as described previously 37 . Extracted PBMCs were subjected to either B cells or monocytes isolation using B cell Isolation Kit II and Monocytes Isolation Kit II (Miltenyi Biotec) respectively following manufacturer's instructions. Purity was > 95% as verified by flow cytometry. . Enhanced infection-associated lethality in young mice. (a) 11-day old C57BL/6 (female, n = 10 animals per group) were inoculated intradermally with 10 6 PFU of CHIKV-21. Immediately after, these mice were given intraperitoneally either human naive polyvalent antibodies or purified CHIKVIGs at different concentrations. Survival of these animals was monitored over a period of 3 weeks. (b,c) 11 days old C57BL/6 (female, n = 3 animals per group) were infected as described in (a) but were intraperitoneally given purified human CHIKVIGs at 10 µg/kg. Control animals were given 10 µg/kg of human naive polyvalent antibodies. Viral RNA load in the serum, liver and muscle were determined at both (b) 3 and (c) 6 dpi. All data are presented as mean ± SD. *p < 0.05 by parametric unpaired t test.