Healthy and Patient Type 2 Innate Lymphoid Cells are Differently Affected by in vitro Culture Conditions

Abstract

Background

Type 2 innate lymphoid cells (ILC2s) have emerged as key players in the development of type 2 driven diseases such as allergy and asthma. Due to their low number in the circulation, in vitro expansion is needed to unravel their mechanisms of action.

Purpose

The aim of this study is to assess the impact of different culture conditions and address whether the method of expansion may distinctly affect healthy donor or patient-derived ILC2s.

Methods

Here, we described the impact of six different culture conditions on the proliferation, phenotype and function of human ILC2s freshly obtained from healthy donors (healthy ILC2s) and allergic patients (patient ILC2s).

Results

We showed that the cytokine cocktail or the PHA induced the highest proliferation of healthy ILC2s and patient ILC2s, respectively. We observed that the stromal cells OP9, used as ILC2 feeders, did not boost their proliferation, but impaired the activation marker expression and the function of patient ILC2s. Furthermore, we demonstrated that the culture conditions differently impacted the activation state of c-Kit^high and c-Kit^low ILC2s, in both healthy donors and allergic patients. Last, we also observed that ILC2s expanded only with IL-2 and IL-7 were the most prone to secrete IL-5 and IL-13 upon IL-33 stimulation. In contrast, in patients, the addition of OP9 cells during the expansion restrained their type 2 cytokine secretory functions.

Conclusion

This report highlights that culture conditions distinctly impacted on the healthy or patient ILC2 behavior, with important consequences for their study in disease settings.

Keywords:

• type 2 innate lymphoid cells
• in vitro expansion
• allergic patients
• cytokines

Ethics Approval and Informed Consent

Venous blood was collected at the local Blood transfusion center, upon written informed consent and in accordance with the Declaration of Helsinki. Allergic patient blood samples were obtained from the University Hospital of Geneva (HUG) in the frame of the CCER 2017-00544 protocol, approved by the local Ethical Committee (Commission cantonale d’éthique de la recherche CCER, Rue Adrien-Lachenal 8, 1207 Geneva) and upon written informed consent. The CCER is the overarching authority responsible for all studies in the canton of Geneva, including the ones performed at HUG. Dr Jandus is affiliated with HUG.

Acknowledgments

We thank healthy donors and patients for the participation to this study. This work was supported by grant from the Swiss National Science Foundation (PRIMA_PR00P3_179727) to CJ and Fondazione Umberto Veronesi to GE.

Data available on request from the authors https://doi.org/10.26037/yareta:kjxpl2iuwjhprnv3gudbuoasdm.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors declare no conflicts of interest in this work.