Yellow fever vaccine-associated neurologic and viscerotropic disease: a 10-year case series of the French National Reference Center for Arboviruses with clinical and immunological insights

A sensitive assay for measuring whole-blood responses to type I IFNs

Human inborn errors of the type I IFN response pathway and auto-Abs neutralizing IFN-α, -β, and/or -ω can underlie severe viral illnesses. We report a simple assay for the detection of both types of condition. We stimulate whole blood from healthy individuals and patients with either inborn errors of type I IFN immunity or auto-Abs against type I IFNs with glycosylated human IFN-α2, -β, or -ω. As controls, we add a monoclonal antibody (mAb) blocking the type I IFN receptors and stimulated blood with IFN-γ (type II IFN). Of the molecules we test, IP-10 (encoded by the interferon-stimulated gene (ISG) CXCL10) is the molecule most strongly induced by type I and type II IFNs in the whole blood of healthy donors in an ELISA-like assay. In patients with inherited IFNAR1, IFNAR2, TYK2, or IRF9 deficiency, IP-10 is induced only by IFN-γ, whereas, in those with auto-Abs neutralizing specific type I IFNs, IP-10 is also induced by the type I IFNs not neutralized by the auto-Abs. The measurement of type I and type II IFN-dependent IP-10 induction therefore constitutes a simple procedure for detecting rare inborn errors of the type I IFN response pathway and more common auto-Abs neutralizing type I IFNs.

The Chimeric Chaoyang-Zika Vaccine Candidate Is Safe and Protective in Mice

Zika virus (ZIKV) is an emerging flavivirus that causes congenital syndromes including microcephaly and fetal demise in pregnant women. No commercial vaccines against ZIKV are currently available. We previously generated a chimeric ZIKV (ChinZIKV) based on the Chaoyang virus (CYV) by replacing the prME protein of CYV with that of a contemporary ZIKV strain GZ01. Herein, we evaluated this vaccine candidate in a mouse model and showed that ChinZIKV was totally safe in both adult and suckling immunodeficient mice. No viral RNA was detected in the serum of mice inoculated with ChinZIKV. All of the mice inoculated with ChinZIKV survived, while mice inoculated with ZIKV succumbed to infection in 8 days. A single dose of ChinZIKV partially protected mice against lethal ZIKV challenge. In contrast, all the control PBS-immunized mice succumbed to infection after ZIKV challenge. Our results warrant further development of ChinZIKV as a vaccine candidate in clinical trials.