Authors: Wilson-Welder Jennifer, Mansfield Kristin, Han Sushan, Hoenes Brock, Alt David, Humphrey Sam, Olsen Steven C
Journal: Frontiers in veterinary science
Summary
# Editorial Summary Treponema bacteria are causing severe, often devastating hoof disease in wild elk populations across the Pacific Northwest, yet little is known about the immune mechanisms that might protect against or exacerbate this condition. Wilson-Welder and colleagues investigated lymphocytic responses to treponemal antigens in live-captured female elk from endemic areas, measuring serum antibody titres, B cell activation, and T cell proliferation (both conventional CD4+/CD8+ and gamma-delta subsets) in relation to disease stage. Animals with advanced lesions demonstrated elevated antibody titres and increased antigen-reactive B cells compared to healthy or naive elk, alongside proliferative CD4+ and CD8+ responses; gamma-delta T cells were notably present in early-stage disease, suggesting a potential early-stage immune signature. Contrary to expectation, high antibody titres did not confer protection, and naturally healthy animals showed minimal lymphocytic responses, indicating that acquired immunity to this infection is likely rare. The findings suggest that treponeme-driven hoof diseases may overwhelm normal immune defences or establish persistent infections despite robust serological responses, with gamma-delta T cells representing an intriguing but poorly understood component—warranting investigation into whether their observed skin-homing capabilities translate to meaningful protection or pathogenic involvement in affected livestock and companion animals.
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Practical Takeaways
- •Treponema-associated hoof disease in cervids shows poor natural immunity development; vaccination strategies may need to be explored as prevention unlikely through natural exposure
- •High antibody titers do not indicate protection against this hoof disease, suggesting humoral immunity alone is insufficient for disease control
- •Gamma-delta T cell involvement in early lesions may represent a distinct immunological mechanism worth investigating for therapeutic intervention
Key Findings
- •Serum antibody titers to treponemal antigens correlated with disease severity but did not reduce disease progression in affected elk
- •T lymphocytic responses (CD4+ and CD8+) were mildly proliferative to treponemal antigen and correlated with advanced lesion stages
- •Gamma-delta T cells proliferated in response to treponeme antigen in early-stage lesions, suggesting potential role in disease pathogenesis
- •Naturally acquired immunity to treponema-driven hoof disease appears to be rare, with healthy animals showing low lymphocytic responses