CD4 and Zika virus infectious disease: Endpoint reciprocal titers (Fig. 4b) showed that all patients with previous ZIKV infection have high mean titer of 3.84 and Z12 had the highest titer of 5.34 using Env-CD4 whilst commercial Env showed a significantly lower mean titer of 3.16 and Z12 had the titer of 4.38.