Does IL-4 Play a Role in the Expansion of Vβ8a T Cell Receptor-Bearing Cells?

Abstract

Background: Peripheral blood mononuclear cells (PBMC) of subjects allergic to the insect-derived allergen Chi t 1–9 are characterized by an allergen-induced pronounced proliferation and increased expression of activation markers (CD25, HLA-DR, CD23). T cell lines showed an elevated percentage of Vβ8a-positive cells following stimulation by Chi t 1–9. Objective: The aim of the present study was to investigate whether Vβ8a dominance plays an important role in PBMC short-term cultures (24 h) as well. The role of exogenous added cytokines, especially IL-4, has been determined. Methods: The T cell receptor repertoire was measured with 16 monoclonal antibodies to epitopes on the variable region of the β chain by flow cytometry. Patients allergic to Chi t 1–9 were compared to nonallergic subjects as well as to subjects with other occupational allergies. In addition, cytokines were determined intracellulary by flow cytometry. Studies were performed with PBMC cultured for 24 h. Results: After cultivation for 24 h without or with different stimuli (cytokines, allergen, phytohaemagglutinin), changes in the T cell receptor profile and the cytokine profile were measurable compared to the baseline value (without cultivation). Stimulation with IL-4 revealed increased percentages of Vβ8a-expressing cells in Chi t 1–9-sensitized patients. This IL-4-induced Vβ8a increase did not occur in PBMC from the two control subject groups (non-allergic and allergic to other allergens than Chi t 1–9). Conclusion: In conclusion, the dominance of certain T cell receptor types seems to arise due to the exposure to specific allergens and cytokine production. Some T cell receptors are often affected, for example Vβ8a, whereas others only show minor variations. Vβ8a expression obviously plays an important role in Chi t 1–9 allergy.

T-Cell Receptor and Allergy - A Survey

“…Untersuchungen mit dem Allergen Chi t 1 ± 9, einem Insektenhämoglobin, ergaben, dass Zell-Linien der Chi t 1 ± 9 Allergiker einen gegenüber nicht stimulierten Zellen signifikant erhöh-ten Anteil Vâ8a-positiver T-Zellen aufwiesen [21,22]. Untersucht man die TCR-Expression auf PBMC von Chi t 1 ± 9 Allergikern direkt nach der Blutabnahme (Basisprofil), sind keine signifikanten Unterschiede zu PBMC nicht-Chi t 1 ± 9-allergischer Probanden feststellbar, die individuellen Unterschiede sind allerdings groû ± ein Hinweis darauf, dass neben der genetischen Grundausstattung viele Faktoren das aktuelle TCR-Profil beeinflussen.…”