A. Menssen et al., Analysis of the TCRBV repertoire of T cells in normal, human skin: Evidence for a restricted diversity, J INVES DER, 115(1), 2000, pp. 66-73
alpha beta T cells constitute an important component in the first line of i
mmunologic defense in human skin. In order to determine the local selection
forces driving T cell diversity, we studied the T cell receptor repertoire
in normal human skin and compared it with that of matched blood samples. U
sing semiquantitative reverse transcription-polymerase chain reaction the e
xpression of T cell receptor beta-chain V genes was determined. The majorit
y of skin, but not blood T cells, revealed a bias towards usage of T cell r
eceptor beta-chain V2 and V6. Whereas sequencing of T cell receptor beta-ch
ain V2 and V6 polymerase chain reaction products showed a heterogeneous clo
nal distribution within these beta-chain V gene families, the analysis of o
ther selected either over- or underrepresented beta-chain V gene families (
BV3, BV12, BV13S1, BV17) revealed numerous identical T cell receptor beta-c
hain V transcript sequences that were not detected in blood. Restricted T c
ell receptor diversity in terms of beta-chain V gene preferences or clonal
expansion was observed in skin samples of donors from all ages (0.5-87 y).
Hence, the repertoire of T cells in normal human skin is apparently subject
ed to skin-specific selection throughout life. According to our data, this
process could involve superantigens, which favor polyclonal accumulation of
T cells using certain beta-chain V genes, as well as antigens, which induc
e clonal T cell expansion. Our results furthermore indicate, that T cell re
ceptor beta-chain V repertoire restrictions do not necessarily result from
disease-associated activation of the skin immune system, but could reflect
regular mechanisms of immunologic homeostasis within the epithelial surface
of the body.