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The antigen
presenting cells (APCs)
with special
interest to
dendritic cells
(DC), were
investigated in 28
hypertrophic and 10
control pharyngeal
tonsils of children
by histochemistry,
immunohistochemistry
and electron
microscopy. In this
study, we are trying
to clarify the
function and
classification of
APC in pharyngeal
tonsils using
morphologic criteria,
Human Leukocyte
Antigen Monoclonal
Antibody (HLA-DR
MoAb), which is
specific for APCs,
and acid phosphatase
(APh) reacting with
both phagosomes and
lysosomes.
The surface
epithelium of the
patient group
examined by light
microscopy, heavy
infiltration of
lymphocytes,
degenerated columnar
cells and a few HLA-DR
MoAb (+) columnar
cells was observed.
Additionally, a
significant number
of APCs which were
Langerhans cells (LCs),
interdigitating
dendritic cell (IDC),
follicular dendritic
cell (FDC) and
macrophages were
stained with both
HLA-DR MoAb and APh
in the epithelial,
interfollicular-subepithelial
and follicular areas.
Ultrastructural
examinations
revealed that
lymphocytes,
macrophages, LC and
M cells were
found among the
surface columnar
epithelial cells of
the patient group.
The interactions
between M cells and
LC suggested that M
cells probably
passed antigens from
surface to LC. In
the interfollicular-subepithelial
areas of the
hypertrophic
pharyngeal tonsil,
IDCs were in close
contact with
lymphocytes,
macrophages and
plasma cells. Seven
types of FDCs (FDC-1
- FDC-7) were
recognised according
to their
ultrastructural
appearances.
Differentiated FDCs
(FDC-4) were also in
close contact with
each active subtype
of FDCs in
follicular areas
besides lymphocytes.
These findings
supported the idea
that although the
pharyngeal tonsils
contained several
types of active APCs,
only DC were in
close contact with
immunocompetent
cells and the other
APCs. Therefore,
these morphologic
appearances of DC
could be a sign of
function to initiate
the immune response
of the pharyngeal
tonsil.
Key Words:
Dendritic cell,
Antigen-presenting
cell, Pharyngeal
tonsil, M cell,
Langerhans cell,
Macrophage, Plasma
cell. |
