Helminth Infection-Induced Increase in Virtual Memory CD8 T Cells Is Transient, Driven by IL-15, and Absent in Aged...

Area of Science:

• Immunology
• T cell biology
• Aging research

Background:

• CD8 virtual memory T (TVM) cells are partially differentiated naive T cells responding to cytokines like IL-15.
• TVM cells are highly proliferative in youth but senesce with age, losing function.
• Helminth infection enhances TVM cells and improves subsequent pathogen clearance in young mice.

Purpose of the Study:

• To investigate the proliferative and functional changes in TVM cells versus naive CD8 T cells after helminth infection in young and aged mice.
• To determine the role of IL-15 in helminth-induced TVM cell expansion.
• To identify age-related factors affecting TVM cell responses.

Main Methods:

• Comparative analysis of TVM and naive CD8 T cells from young and aged C57BL/6 mice post-helminth infection.
• Assessment of cell proliferation via TCR and cytokine stimulation.
• Evaluation of IL-15's role in TVM cell expansion.

Main Results:

• Helminth infection increases TVM cells, driven by existing TVM cell proliferation, not naive cell differentiation.
• IL-15 is essential for helminth-induced TVM cell expansion.
• TVM cells exhibit the highest proliferation in response to helminth infection and IL-15.
• Aged TVM cells do not expand after helminth infection due to intrinsic and extrinsic aging factors.

Conclusions:

• Helminth infection promotes TVM cell expansion in a manner dependent on IL-15 and existing TVM cell proliferation.
• Aging impairs TVM cell expansion following helminth infection, highlighting age-associated immune dysfunction.