By Kim Tong-hyung
Staff Reporter
Scientists suggest that harmful T helper 2 (TH2) white blood cells, which are associated with the development of allergic diseases, may also double as effective weapons to combat the conditions.
A group of researchers led by Seoul National University's (SNU) Kang Chang-yuil said they have discovered a technique to convert TH2 cells into regulatory T cells that are linked to the suppression of allergies, which may have important implications for strategies to prevent and control diseases such as asthma.
The possibilities include developing individually-tailored treatments based on a patient's own white blood cells, Kang said.
The human body produces a variety of T helper cells, white blood cells that are at the core of immune responses. T helper 1 cells (TH1) help fight off infections, but TH2 cells set off inflammations that trigger allergic responses. Regulatory T cells switch off this inflammatory mechanism. In the study published by peer-review journal, Proceedings of the National Academy of Sciences (PNAS), Kang and his colleagues claim that TH cells could be "redifferentiated" into another TH lineage, even after the polarization from immature T cells is completed.
The researchers successfully derived regulatory T cells from TH2 memory cells by strengthening the expression of the transforming growth factor beta (TGF-beta) protein, which stimulates the forming of regulatory T cells, with the help of vitamin A metabolite all-trans retinoic acid and rapamycin (ATRA).
The key was to suppress the GATA-3 protein, a T-cell-specific transcription factor, Interleukin-4 (IL-4), a cytokine that induces naive T cells to differentiate into TH2 cells, and a mammalian target of rapamycin (mTOR), a protein which plays a key role in cell growth.
These combine to suppress T cells from converting to regulatory T cells through TGF-beta, according to the report.
The converted regulatory T cells completely lost their TH2 characteristics, suppressing the proliferation of other TH2 cells as well as the production of cytokine.
"Our research shows that it will be possible to separate T cells from the blood of patients and re-inject the cells into them after simple manipulation to treat allergic diseases," Kang said.