Characteristics of naïve CD4⁺T cells recognized staphylococal enterotoxin b superantigen presented by naïve B cells versus monocyte-derived dendritic cells

Abstract

To determine role of human naïve B cell in antigen presentation and stimulation to naïve CD4⁺T cell. To improve the yield and purity of human naïve B cell sepration, we have shown that inclduing B cell enrichment rosetting step prior to magnetic cell sorting, the puriy of the obtained naïve B cel purity was from 90±2.2% to 97±1.0% even when starting from a small blood voulume of 10 ml. The acquired naïve B cells were at the resting state and considered as poor antigen presentng cells as judged by their CD69(-)CD80(lo)CD86(lo) phenotypes. These naïve B cellls could activate naïve CD4⁺T cells by SEB presentation to acquire CD4(+)CD25(+)CD62L(hi)CD95(lo) phenotypes with limited IL-2 and IL-4 producton. Howerver, the SEB-primed CD4⁺T cells had no suppressive function on allo CD4⁺T cells' proliferation. Thus the SEB-pused naïve B cel system could not induce regulatory T cell differentiation. To determine whether naïve B cell from various sources may have different characteristcs, we compared dfferential gene expresson among peripheral, splenic and tonsilar naïve B cell using available data from literatures. The result revealed increased cell activation of lymphoid when compared with peripheral naïve B cell which might also affect their antigen presentation property. However, further warrat in this issue and other contributors were needed to understand the role of naïve B cell in human regulatroy T cel differentiation.