Adaptive immunity to murine skin commensals

Area of Science:

• Immunology
• Microbiology
• Dermatology

Background:

• Commensal skin bacteria are increasingly recognized for their interactions with the adaptive immune system.
• The role of the adaptive immune system in controlling skin commensal bacteria is not well understood.

Purpose of the Study:

• To investigate the recognition of commensal skin bacteria by T cells.
• To determine the role of T cells in controlling skin commensal bacteria populations.

Main Methods:

• Utilized Recombination activating gene 1 (Rag1)(-/-) mice lacking adaptive immune cells.
• Isolated and cultured bacteria from lymph nodes of Rag1(-/-) mice.
• Transferred T cells from normal mice into Rag1(-/-) mice and assessed bacterial load and T cell responses.
• Analyzed cytokine production (IFNγ and IL-17A) and T-cell receptor spectrotype.

Main Results:

• Commensal skin bacteria, including mycobacteria, were found in the lymph nodes of Rag1(-/-) mice.
• T cells from normal mice recognized and proliferated in response to these skin bacteria in vitro.
• Adoptive transfer of T cells reduced bacterial sequences in the skin and lymph nodes of Rag1(-/-) mice.
• The antibacterial effect was dependent on IFNγ and IL-17A cytokines.

Conclusions:

• T cells play a significant role in controlling commensal skin bacteria.
• This T cell-mediated immunity may be crucial for preventing cutaneous and mycobacterial infections, particularly in T-cell-deficient individuals.