Recent Developments in Basophil Research: Do Basophils Initiate and Perpetuate Type 2 T-Helper Cell Responses?

Abstract

Basophils account for only 0.1–1% of all peripheral blood leukocytes. They were considered to be a redundant cell type for a long time. However, several findings show a non-redundant role for basophils in type 2 T-helper cell (Th2) immune responses in helminth infections, allergy and autoimmunity. Both immunoglobulin-E-dependent and -independent pathways have been described to contribute to basophil activation. In addition, several recent studies reported that basophils can function as antigen-presenting cells and are important in the initiation of Th2 immune responses. However, there are also conflicting studies that do not corroborate the importance of basophils in Th2 immune responses. This review discusses the role of basophils in Th2 immune responses in view of these recent findings.

Basophil-associated OX40 Ligand Participates in the Initiation of Th2 Responses during Airway Inflammation

“…Numerous studies have demonstrated that basophils not only play crucial roles in the effector phase, but also critically participate in the initiation of Th2-centered immune responses (7)(8)(9)(10)(11). Using an ovalbumin (OVA)-induced allergic airway inflammation mouse model, we previously showed that basophils acted as a primary inducer of the Th2 immunity, evident by increased OVA-specific immunoglobulin E (OVA-sIgE) and IL-4 levels both in serum and bronchial alveolar lavage fluid (BALF), and increased proportion of Th2 cells in the spleen after transfusion of lung basophils derived from OVA-challenged mice into wild-type (WT) mice (12).…”

Lymphocyte-Based Model Systems for Allergy Research: A Historic Overview

“…Recent studies concentrated on the investigation of the role of basophils during adaptive immune responses [215]. These studies were complicated due to functional discrepancies between human and mouse basophils [215].…”

“…These studies were complicated due to functional discrepancies between human and mouse basophils [215]. It has been shown that mouse basophils can act as APC [216,217], whereas human basophils were not able to internalize and present allergen to allergen-specific T cells [218] and therefore did not induce T cell proliferation [218,219].…”

The aging immune system and nutritional interventions

“…Purified basophils (BMB) were overnight cultured under five different conditions: medium, IL-18+IL-33, TSLP, IgE, or CD200R3. These conditions mimic different routes of activation of basophils [289]. The five different conditions resulted in distinct basophil phenotypes.…”

“…It is, however, largely unknown what effect age has on basophil differentiation and function. Basophils are granulocytes which are involved in mounting and perpetuating Th2-mediated responses [289]. Basophils are an important source of IL-4 and IL-13, which direct the immune response towards Th2 type responses [290].…”