Three-dimensional Models of the Nasopharynx for the Study of Epstein-Barr Virus Infection

Abstract

The ubiquitous and cancer-associated Epstein-Barr virus (EBV) is associated with nearly all cases of nasopharyngeal carcinoma (NPC). Nasopharyngeal tissue is comprised of both pseudostratified and stratified epithelium, which are modeled in three-dimensional (3-D) cell culture. The cellular origin of EBV-associated NPC is as yet unknown, but both latent and lytic infections are likely important for preneoplastic mechanisms and replenishing the compartmentalized viral reservoir. Conventional 2-D cultures of nasopharyngeal epithelial cells (as primary cells or immortalized cell lines) are difficult to infect with EBV and cannot mimic the tissue-specific biology of the airway epithelium, which can only be captured in 3-D models. We have shown that EBV can infect the pseudostratified epithelium in air-liquid interface (ALI) culture using primary conditionally reprogrammed cells (CRCs) derived from the nasopharynx. In this protocol, we provide a step-by-step guide for the (i) conditional reprogramming of primary nasopharyngeal cells, (ii) differentiation of CRCs into pseudostratified epithelium in ALI culture (known as pseudo-ALI), and (iii) EBV infection of pseudo-ALI cultures. Additionally, we show that nasopharyngeal CRCs can be grown as organotypic rafts and subjected to EBV infection. These nasopharyngeal-derived 3-D cell cultures can be used to study EBV latent and lytic infection in relation to cell type and donor variation, by immunostaining and single-cell RNA-sequencing methods ( Ziegler et al., 2021 ). These methods are useful for studies of EBV molecular pathogenesis, and can overcome many of the limitations associated with conventional 2-D cell cultures. Graphic abstract: Workflow of nasopharyngeal-derived conditionally reprogrammed cells grown into pseudostratified-ALI and organotypic rafts in 3-D cell culture. Created with Biorender.com.

Keywords: 3-D model; Air-liquid interface (ALI); Epstein-Barr virus (EBV); Nasopharyngeal epithelium; Nasopharynx; Organotypic rafts; Pseudostratified.