Germinal center B cells constitute a predominant physiological source of IL-4: Implication for Th2 development in vivo

Summary, in English

Protective immunity depends upon the capability of the immune system to properly adapt the response to the nature of an infectious agent. CD4+ Th cells are implicated in this orchestration by secreting a polarized pattern of cytokines. Although Th2 development in animal models and in human cells in vitro to a large extent depends on IL-4, the nature of the cells that provide the initial IL-4 in vivo is still elusive. In this report, we describe the anatomical localization as well as the identity of IL-4-producing cells in human tonsil, a representative secondary lymphoid organ. We demonstrate that IL-4 production is a normal and intrinsic feature of germinal center (GC) B cells. We also show that expression of IL-4 is highly confined to the GCs, in which the B cells constitute the prevalent cellular source. Furthermore, immunofluorescence analysis of colon mucosa reveals a strikingly similar pattern of IL-4-expressing cells compared with tonsils, demonstrating that IL-4 production from GC B cells is not a unique feature of the upper respiratory tract. Our results show that GCs provide the most appropriate microenvironment for IL-4-dependent Th2 polarization in vivo and imply a critical role for GC B cells in this differentiation process.

• Author: Bengt Johansson-Lindbom; Carl Borrebaeck
• Department/s: Department of Immunotechnology
• Publishing year: 2002
• Language: English
• Pages: 3165-3172
• Publication/Series: Journal of Immunology
• Volume: 168
• Issue: 7
• Document type: Journal article
• Publisher: American Association of Immunologists
• Topic: Immunology in the medical area
• Status: Published
• ISBN/ISSN/Other: ISSN: 1550-6606