Evidence for endocytotic mechanisms in the epidermal Langerhans cells.

Rolf Elofsson, Anders Andersson, Bengt Falck, Steinar Sjöborg

Research output: Contribution to journalArticlepeer-review


When the Langerhans cells (LC) are prepared for
electron microscopy with an osmotically balanced prefixative,
they display their classical criteria, but in addition
they are provided with numerous microvilli and contain
pinocytotic vesicles. In cross-sections the specific discshaped
granules are visualized as rod-like profiles limited by
a trilaminar membrane similar to the cell membrane. In
face-on projection the electron density of a single granule is
too low to permit its observation. It ts suggested that the
racquet-shaped profile bounded by a non-trilaminar membrane,
regarded as classical, is a fixation artifact. The view
is advanced that the Birbeck granules are formed by a process
implying a superimposition of membrane folds. The
occurrence of phagocytosed melanosomes seems to be a
normal phenomenon.
The LC are highly activated in contact allergic dermatitis,
as expressed by an increase in number, a polarization
of dendrites towards the surface and the appearance of
membrane active zones characterized by intense membrane
folding, combined with a formation of pinocytotic vesicles
and specific granules. Challenging sensitized skin with
nickel leads to the occurrence of dark vesicles which probably
lack a limiting membrane. It is concluded that the LC
show endocytotic activity and that they constitute an
important defense system in the epidermis, i.e., capable of
capturing extracellular (endogenous or exogenous) material
via different routes.
Original languageEnglish
Pages (from-to)29-39
JournalActa dermato-venereologica. Supplementum
Publication statusPublished - 1981

Subject classification (UKÄ)

  • Zoology


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