Ex vivo engineered immune organoids for controlled germinal center reactions

Abstract

Ex vivo engineered three-dimensional organotypic cultures have enabled the real-time study and control of biological functioning of mammalian tissues. Organs of broad interest where its architectural, cellular, and molecular complexity has prevented progress in ex vivo engineering are the secondary immune organs. Ex vivo immune organs can enable mechanistic understanding of the immune system and more importantly, accelerate the translation of immunotherapies as well as a deeper understanding of the mechanisms that lead to their malignant transformation into a variety of B and T cell malignancies. However, till date, no modular ex vivo immune organ has been developed with an ability to control the rate of immune reaction through tunable design parameter. Here we describe a B cell follicle organoid made of nanocomposite biomaterials, which recapitulates the anatomical microenvironment of a lymphoid tissue that provides the basis to induce an accelerated germinal center (GC) reaction by continuously providing extracellular matrix (ECM) and cell–cell signals to naïve B cells. Compared to existing co-cultures, immune organoids provide a control over primary B cell proliferation with ~100-fold higher and rapid differentiation to the GC phenotype with robust antibody class switching.

EZH2 enables germinal centre formation through epigenetic silencing of CDKN1A and an Rb-E2F1 feedback loop

“…Moreover it is well accepted that simply activating resting B cells ex vivo does not recapitulate the GC phenotype 1 . To overcome this challenge we optimized a three-dimensional (3D) B cell follicular organoid culture system based on work published by Purwada et al 12, 13 and determined whether this system could mimic the phenotypic and transcriptional regulatory characteristics of primary GC B cells. This culture system provides the opportunity to generate hundreds of 3D organoids using B cells from one spleen.…”

BAFF, IL‐4 and IL‐21 separably program germinal center‐like phenotype acquisition, BCL6 expression, proliferation and survival of CD40L‐activated B cells in vitro

“…Elucidating the regulatory signals driving and programing GC B cell behaviors is key; however, the comparatively short life‐span of GC B cells ex vivo makes their direct study difficult and costly. There is also difficulty in recapitulating this dynamic, multi‐dimensional process in vitro , but culture methods have become more accessible, with significant advances toward in vitro genesis of GC‐like cells coming in recent years …”

Immune engineering: From systems immunology to engineering immunity

“…Applying the synthetic biology approach, Wendell Lim’s group recently demonstrated versatile functionalities and activation states that engineered T cells have by taking advantage of specific transcriptional responses induced by customized synthetic Notch receptor/ligand interactions [92]. Additionally, efforts in engineering immunity via engineering the microenvironment using scaffolds [93,94] or organoid culture [95,96] have paved the way of applying in vitro engineered immune cells for therapeutics. With continued development of high-throughput technology and synthetic biology tools, immune engineering will be a critical link between basic immunology discoveries and their application.…”