# Engineering Adaptive Immunity in 3D: A Patient‐Specific Lymphoid Model Using Stromal Networks and Peripheral Blood Mononuclear Cells

## TL;DR

Researchers created a 3D model of lymphoid tissue using stem cells and immune cells to study adaptive immunity and test vaccines.

## Contribution

A novel 3D lymphoid model using adipose-derived stem cells and PBMCs enables personalized immune response studies.

## Key findings

- The model supports antigen-specific B cell activation and IgM secretion.
- FRCP1 and FRCP2 stromal subsets show distinct immune-modulating functions.
- The system mimics Th1 and Th2 cytokine environments for immune profiling.

## Abstract

Tertiary lymphoid organs (TLOs) are non‐encapsulated immune structures that emerge in response to chronic inflammation, orchestrating local adaptive immune responses. However, recapitulating their complexity in vitro remains challenging due to the difficulty in generating  physiologically relevant stromal‐immune interactions. Here, a 3D lymphoid tissue model is presented, engineered using human adipose‐derived stem cells (ADSCs) differentiated into fibroblastic reticular cell (FRC)‐like populations within collagen matrices. Differentiation is induced using TNF‐α and LT‐α, with or without IL‐4, generating two stromal phenotypes: FRCP1 and FRCP2. These subsets exhibit matrix remodeling, distinct transcriptional signatures, and surface markers consistent with lymph node‐resident T cell reticular and follicular dendritic cell subsets. Upon co‐culture with peripheral blood mononuclear cells (PBMCs) and SARS‐CoV‐2 S1‐primed mature dendritic cells, the model supports antigen‐specific B cell activation and cytokine environments indicative of Th1 or Th2 polarization. FRCP1 favors B cell support and IgM secretion, whereas FRCP2 promotes dendritic cell activation and Th1‐type chemokine expression. This platform demonstrates the functional diversification of stem cell‐derived FRC‐like subsets and their role in orchestrating immune microenvironments. It enables investigation of lymphoid tissue remodeling, stromal‐immune crosstalk, and antibody generation using total PBMCs, providing a scalable, customizable system for personalized vaccine screening, autoimmune modeling, and therapeutic development.

This study presents a 3D lymphoid tissue model engineered from adipose‐derived stem cells differentiated into fibroblastic reticular cell–like networks and co‐cultured with immune cells. The engineered system successfully generates antigen‐specific antibodies and cytokine responses, providing a platform for studying adaptive immunity, vaccine efficacy, and personalized immunotherapy in vitro.