Human atopen-specific types 1 and 2 T helper cell clones.

Area of Science:

• Immunology
• Cellular Biology

Background:

• T lymphocyte clones (TLC) from atopic and nonatopic donors exhibit distinct cytokine profiles.
• CD4+ T cells play a crucial role in immune responses, differentiating into various subsets with specialized functions.

Purpose of the Study:

• To compare the functional characteristics of T lymphocyte clones (TLC) from atopic and nonatopic individuals.
• To investigate the role of Th1 and Th2 cells in IgE synthesis and cellular cytotoxicity.

Main Methods:

• Comparative analysis of T lymphocyte clones (TLC) from atopic and nonatopic donors.
• Cytokine profile assessment (IL-4, IL-5, IL-6, TNF-alpha, GM-CSF, IFN-gamma, IL-2) upon stimulation.
• Investigation of IgE synthesis in co-cultures with B cells.
• Evaluation of cytolytic activity against autologous antigen-presenting cells (APC).

Main Results:

• Atopic TLC resembled Th2 cells, secreting high levels of IL-4, IL-5, IL-6, TNF-alpha, and GM-CSF, with minimal IFN-gamma and IL-2.
• Nonatopic TLC resembled Th1 cells, secreting high levels of IFN-gamma, IL-2, TNF-alpha, and GM-CSF, with no IL-4 and little IL-5.
• Atopic Th2 clones induced IgE synthesis in B cells, dependent on IL-4 and an additional helper function.
• Nonatopic Th1 clones exhibited antigen-specific cytolytic activity against autologous APC.

Conclusions:

• The study provides clear evidence for the existence and distinct functions of Th1 and Th2 cells in humans.
• Atopic Th2 cells are potent inducers of IgE synthesis, while nonatopic Th1 cells possess cytolytic capabilities.
• These findings highlight the differential roles of T helper cell subsets in allergic and immune responses.