Quantification of a Selective Expansion of T Cell Receptor Vβ by Superantigen Using Real-Time PCR

The interplay between epidermal barrier distribution, microbiota composition, and immune infiltrate defines and stratifies psoriasis patients and is associated with disease severity

Psoriasis is a chronic inflammatory autoimmune skin disease characterized by keratinocyte hyperproliferation, primarily driven by the IL-23/IL-17 axis. In addition to immune response, various skin components, including the epidermal barrier and the skin microbiota, have been individually implicated in the disease pathogenesis. Here, we aimed to investigate the interplay between epidermal tight junctions, Staphylococcus aureus enterotoxin B (SEB), and CD4 T cell-mediated immune responses. By immunofluorescence analyses of skin biopsies, we observed that claudin-1 distribution was significantly altered in psoriatic patients, which correlated with the localization of Staphylococcus aureus and SEB across skin layers and with disease severity. Furthermore, functional CD4 TCRvβ17 cells were associated with SEB presence in patients skin and positively correlated with psoriasis severity. Notably, in patients with SEB detected in the dermis, CD4 TCRvβ17 IL-17 cells were linked to barrier abnormalities. Unsupervised analysis stratified psoriasis patients into three groups based on SEB presence and location, supporting the previous findings. The patient group with SEB in the dermis exhibited improved responses to biological therapy, including reductions in PASI score, claudin-1 fragmentation, S. aureus and SEB presence, and CD4 TCRvβ17 cell percentages. Our findings emphasize the complex interplay between epidermal barrier distribution, SEB localization, and functional CD4 TCRvβ17 cells in psoriatic skin, highlighting their potential in patient stratification in association with the severity of the disease.

Bovine Staphylococcus aureus Superantigens Stimulate the Entire T Cell Repertoire of Cattle

Superantigens (SAgs) represent a diverse family of bacterial toxins that induce Vβ-specific T cell proliferation associated with an array of important diseases in humans and animals, including mastitis of dairy cows. However, an understanding of the diversity and distribution of SAg genes among bovine Staphylococcus aureus strains and their role in the pathogenesis of mastitis is lacking.

Superantigens (SAgs) represent a diverse family of bacterial toxins that induce Vβ-specific T cell proliferation associated with an array of important diseases in humans and animals, including mastitis of dairy cows. However, an understanding of the diversity and distribution of SAg genes among bovine Staphylococcus aureus strains and their role in the pathogenesis of mastitis is lacking. Population genomic analysis of 195 bovine S. aureus isolates representing 57 unique sequence types revealed that strains encode 2 to 13 distinct SAgs and that the majority of isolates contain 5 or more SAg genes. A genome-scale analysis of bovine reference strain RF122 revealed a complement of 11 predicted SAg genes, which were all expressed in vitro. Detection of specific antibodies in convalescent cows suggests expression of 7 of 11 SAgs during natural S. aureus infection. We determined the Vβ T cell activation profile for all functional SAgs encoded by RF122, revealing evidence for bovine host-specific activity among the recently identified RF122-encoded SAgs SElY and SElZ. Remarkably, we discovered that some strains have evolved the capacity to stimulate the entire T cell repertoire of cattle through an array of diverse SAgs, suggesting a key role in bovine immune evasion.