De. King et al., Photodynamic alteration of the surface receptor expression pattern of murine splenic dendritic cells, SC J IMMUN, 49(2), 1999, pp. 184-192
The photosensitizer benzoporphyrin-derivative monoacid ring A (BPD-MA, vert
eporfin), in combination with visible light irradiation, a clinical procedu
re termed photodynamic therapy (PDT), has immunomodulatory activity in vari
ous mouse models. We studied the impact of BPD-MA and light upon DBA/2 mous
e splenic dendritic cells (DC), a potent antigen-presenting cell (APC) type
. DC treated with nanomolar amounts of BPD-MA and 690 nm wavelength light h
ad a reduced capacity to stimulate the proliferation of alloreactive T cell
s. Treatment with BPD-MB and light reduced DC levels of major histocompatib
ility (MHC) Class I and II antigens, intercellular adhesion molecule-1 (ICA
M-1, CD4), the costimulatory B7-1 (CD80) and B7-2 (CD86) molecules, leucocy
te common antigen CD45, the apoptosis-regulating Fas (CD95) receptor and th
e integrin CD11c. In contrast, DC expression of leucocyte function-associat
ed-1 (LFA-1, CD11a), Mac-1 (CD11b), integrin beta(2) chain (CD18) and the D
EC-205 receptor increased, while CD40 levels were relatively unchanged 24 h
after the treatment. MHC Class I and ICAM-1 levels decreased to 40% Of con
trol levels within 2 h following the photodynamic treatment. In the absence
of light, BPD-MA did not affect DC receptor levels. Changes in DC receptor
levels produced by BPD-MA and red light were similar to those produced by
ultraviolet B light irradiation. The photodynamic treatment of activated sp
lenic B cells, a sepal-ate APC class, had little effect upon receptor expre
ssion, except that MHC Class II levels were moderately decreased 24 h later
. Changes in DC receptor expression may contribute to the immunomodulatory
action of PDT.