Figures 1, 2 and 3 were printed in black and white. They should have been printed
in colour as shown.
Figure 1
Expression of P2X5 and P2X7 receptors in paraffin sections of normal human skin. Nuclei
were counterstained blue with haematoxylin. (a) In normal skin, P2X5 immunoreactivity
(brown) was found in basal keratinocytes (B) (although this was not easy to distinguish
from melanin), and in the stratum spinosum (SS), and in very few cells in the stratum
granulosum (SG). P2X5 receptor staining was absent from the stratum corneum (SC),
apart from at the outer edge. P2X5 receptor staining was confined largely to the cell
membranes in the basal layer, and found in the cytoplasm, and occasionally in the
nucleus in both basal and suprabasal keratinocytes. Scale bar. 25 μm. (b) P2X7 immunoreactivity
(pink) was present in the epidermis of all normal skin samples, and was associated
with cells and cell fragments (arrow) in the stratum corneum (SC). Note the brown
melanin in the basal layer (B). Scale bar, 25 μm. (c) There was residual staining
of the outermost edge of the stratum corneum (arrow) with the P2X5 receptor antibody
no primary control, and therefore this was non-specific staining. Note the brown melanin
in the basal layer (B). Scale bar, 25 μm. (d) There was no staining in the no primary
control for the P2X7 receptor antibody Scale bar, 25 μm.
Figure 2
Expression of P2X5 and P2X7 receptors in paraffin sections of human warts. Nuclei
were counterstained blue with haematoxylin. (a) Low power view of P2X5 immunoreactivity
(brown) in the wart. P2X5 receptors were present within the keratinocytes of the wart.
There was marked hyperkeratosis (H), which was negative for P2X5 receptors, although
areas of parakeratosis were positive (arrow). At the outer edge of the stratum corneum
there was a band of heavy staining (asterisk). P2X5 receptors were also found in the
inflammatory cell infiltrate (I) above the stratum corneum (SC). There was a prominent
granular layer (SG), within which cells (koilocytes) showed typical cytoplasmic vacuolation
(arrowheads). Scale bar. 100 μm. (b) Low power view of P2X7 immunoreactivity (pink)
in the wart. P2X7 receptors were strongly present within the hyperkeratotic (H) areas
of the stratum corneum (SC), but not in areas of parakeratosis (arrow). P2X7 receptors
were weakly present in the wart keratinocytes, and mainly found in the nucleus. P2X7
receptors were also weakly found in the inflammatory cell infiltrate (I) above the
stratum corneum. Scale bar, 100 μm. (c) High power view of P2X5 immunoreactivity (brown)
in wart keratinocytes. There were a few positive cells in the basal layer (B), but
most of the positively stained cells were in the suprabasal layers. Koilocytes showed
P2X5 receptor staining in the nucleus (arrowheads). Scale bar, 50 μm. (d) P2X7 immunoreactivity
(pink) was present in the suprabasal layers of the wart, in either large, flat nuclei
with an obvious nuclear membrane (arrow), or in koilocytes, where the receptor was
prominent in shrunken, pynotic nuclei, (arrowheads). P2X7 receptors were not found
in the basal layer (B) of the wart. Scale bar, 50 μm. (e) There was residual staining
of the outermost edge of the stratum corneum (asterisk) with the P2X5 receptor antibody
no primary control, and therefore this was non-specific staining. Scale bar, 100 μm.
(f) There was no staining in keratinocytes of the wart with the P2X5 receptor antibody
no primary control. There was some melanin in the basal layer (B) of the wart. Scale
bar, 50 μm.
Figure 3
Expression of P2X5 and P2X7 receptors in paraffin sections of raft cultures of normal
human keratinocytes and of CIN 612 (HPV 31) cells. Nuclei were counterstained blue
with haematoxylin. (a) P2X5 immunoreactivity (brown) was present throughout all layers
of the raft cultures of normal human foreskin keratinocytes, where the staining was
confined largely to the cell membranes and the cytoplasm. The raft culture was supported
on a collagen matrix (C). Scale bar. 25 μm. (b) P2X7 immunoreactivity (pink) was present
in the raft cultures of normal human foreskin keratinocytes, staining weakly within
the uppermost layer (arrows). Scale bar. 25 μm. (c) P2X5 immunoreactivity(brown) was
present in the CIN 612 (HPV 31) raft keratinocytes, staining all layers of the raft.
Scale bar. 50 μm. (d) P2X7 immunoreactivity (pink) was present in the CIN 612 raft
and was associated with the cell cytoplasm and nucleus (arrow). Scale bar. 50 μm.
(e, f) High power views of CIN 612 (HPV 31) raft cultures: the uppermost layers are
highly disorganised, with nucleated cells at the surface of the raft (arrows). There
was also positive staining in the cytoplasm of mitotic cells (double arrows) within
the raft for both (e) P2X5 receptors (brown) Scale bar 25 μm. and (f) P2X7 receptors
(pink). Scale bar. 25 μm.