Do epidermal cells produce thymic hormones in vivo? An immunohistochemical study using anti-thymic hormone antibodies.
Nicolas. J F JF; Auger. C C; Dardenne. M M; Thivolet. J J
Key Findings
- Antibodies that detect thymic hormones bind to thymic tissue but not to normal skin for the well‑characterized hormones.
- Only anti‑FTS and anti‑thymopoietin antisera showed some staining in skin, but this was due to cross‑reactivity, not actual hormone production.
- Conclusion: epidermal cells do not produce thymic hormones like thymosin‑alpha‑1 in vivo.
Practical Outcomes
- For biohackers, this means you can’t count on your skin to supply thymosin‑alpha‑1; any therapeutic effect will require external supplementation. The paper doesn’t suggest new dosing or usage protocols.
Summary
The study shows that human and mouse skin cells don’t naturally make the thymic hormones thymosin‑alpha‑1, thymopoietin, or FTS/thymulin, meaning any boost from these peptides has to come from outside the body, not from the skin itself.
Abstract
Cultured human epidermal cells have been shown to produce soluble factors endowed with T cell differentiating activities. In addition, the presence of thymopoietin and FTS/thymulin-like factors has been reported in normal human and mouse epidermis using immunohistochemical methods and anti-thymic hormone antibodies. The present study was conducted to re-evaluate the presence of thymic hormones in normal epidermal cells using a panel of monoclonal antibodies (mAbs) and rabbit antisera to several well characterized thymic factors. The reactivity of the following antibodies was tested by indirect immunofluorescence on human and mouse tissue sections: a) two anti-FTS/thymulin mAbs; b) one anti-FTS/thymulin rabbit antiserum; c) one anti-thymopoietin rabbit antiserum; d) one anti-thymosin alpha 1 mAb. Our results show that: 1) all five antibodies reacted with human and/or mouse thymic epithelial cells; 2) none of the 3 antithymic hormone mAbs (2 anti-FTS/thymulin and 1 anti-thymosin alpha 1 mAbs) reacted with normal skin; 3) only 2 out of 5 antibodies, namely the anti-FTS and anti-thymopoietin antisera cross-reacted with mouse and human epidermis and labeled keratinocytes, as previously reported; these latter 2 antibodies also stained nude mouse epidermal cells and labeled non-thymic, non-epidermal normal mouse epithelial tissues, suggesting that the cross-reactive epitope is common to a number of epithelial cells; 4) the antigen defined by the anti-FTS and anti-thymopoietin antisera was not related to keratins, since absorption experiments using purified human epidermal keratins failed to abolish staining of the epidermis. We conclude from this study that epidermal cells do not produce in vivo the well characterized thymic hormones: FTS/thymulin, thymopoietin and thymosin alpha 1. The precise nature of the antigenic structure recognized within epidermis by the anti-FTS and anti-thymopoietin antibodies remains to be defined.
Study Information
pubmed