Preparation and evaluation of antisera for immunohistochemical detection of Zika virus in aldehyde-fixed tissues

Introduction: The nervous system is one of the main targets of the Zika virus. It is essential to have biological reagents to use as diagnostic support and in pathogenesis research that requires aldehyde-fixed tissues. Objective: To determine the utility of two types of antiserums prepared for the detection of Zika virus antigens in cells and tissues fixed in aldehydes. Materials and methods: The antiserums were produced in two New Zealand rabbits from a viral isolate from the 2016 Zika outbreak in Colombia. Freund’s adjuvant was used for boosting in one of the animals, while Montanide adjuvant was used in the other. Immunoreaction titrations were performed on Zika-positive cells and tissues. The streptavidin-alkaline phosphatase and avidin-biotin-peroxidase methods were used. They were evaluated on experimentally infected samples for Zika and other related and unrelated viruses. Performance was evaluated with samples from other techniques used in the laboratory including vibratome sections, high-resolution optical microscopy samples, and transmission electron microscopy. Results: There was immunoreactivity to Zika virus antigens with both antiserums, mainly in neurons of the cerebral cortex. Immunostaining was also demonstrated in cell culture samples and tissues from experimentally infected animals. There was cross- immunoreactivity with dengue and yellow fever viruses but not with rabies virus. Conclusions: The utility of the two antiserums for the detection of Zika virus in samples of human origin and from experimental animals obtained by different histological techniques used for the investigation of Zika virus disease pathogenesis was demonstrated.