Abstract
In this study, by using of near-field scanning optical microscopy (NSOM)/immune-labeling quantum dot (QD)-based dual-color imaging system, we achieved the direct visualization of nanoscale profiles for distribution and organization of CD4 and CD25 molecules in T cells. A novel and interesting finding was that though CD25 clustering as nanodomains were observed on the surface of CD4+CD25high regulatory T cells, these CD25 nanodomains were not co-localized with CD4 nanodomains. This result presented that the formation of these CD25 nanodomains on the surface of CD4+CD25high T cells were not associated with the response of T cell receptor (TCR)/CD3-dependent signal transduction. In contrast, on the surface of CD4+CD25low T cells, CD25 molecules distributed randomly without forming nanodomains while CD4 clustering as nanodomains can be observed; on the surface of CD8+CD25+ T cells, CD25 clustering as nanodomains and co-localization with CD8 nanodomains were observed. Collectively, above these results exhibited that TCR/CD3-based microdomains were indeed required for TCR/CD3-mediated T cells activation and enhanced the immune activity of CD4+CD25low T cells or CD8+CD25+ T cells. In particular, it was found that the formation of CD25 nanodomains and their segregation from TCR/CD3 microdomains were the intrinsic capability of CD4+CD25high T cells, suggesting this specific imaging feature of CD25 should be greatly associated with the regulatory activity of CD4+CD25high T cells. Importantly, this novel NSOM/QD-based dual-color imaging system will provide a useful tool for the research of distribution-function relationship of cell-surface molecules.
Highlights
CD4+CD25high regulatory T cells play an important role in suppression of a wide range of immune responses targeting various microbes, intracellular parasites, allergens, allo-antigens, and tumors [1,2,3,4,5,6]
For CD4+CD25high T cells, using near-field scanning optical microscopy (NSOM)-quantum dot (QD)-based dual-color imaging system, though a lot of CD4 clustering and CD25 clustering with the size of 200–350 nm can be observed on the cell surface (Fig. 4a–c, e–g), but surprisingly, these specific CD25 nanodomains were not co-localized with CD4 nanodomains (Fig. 4d, h)
Combing the immunofluorescence labeling approach and NSOM/QD-based nanoscale imaging technique, several groups and our previous study have demonstrated that T cell receptor (TCR)/CD3 microdomains are required for the full T cells activation, in which a variety of signaling molecules including co-receptor CD4 or CD8 are recruited to TCR/ CD3 microdomains and facilitate T cells activation [12, 14, 20,21,22]
Summary
CD4+CD25high regulatory T cells play an important role in suppression of a wide range of immune responses targeting various microbes, intracellular parasites, allergens, allo-antigens, and tumors [1,2,3,4,5,6]. It has been demonstrated that the effector function and regulatory activity of CD4+CD25high T cells depend at least partially on T cell receptor (TCR)-major histocompatibility complex (MHC) interactions [7]. By using our homemade NSOM/QDbased dual-color imaging system, we intend to directly visualize nanoscale nanospatial relationship between CD4 and CD25 of CD4+CD25high regulatory T cells, further detect whether the distribution and organization of CD25 on the surface of CD4+CD25high T cells are associated with its regulatory activity
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
