Immunosuppressive effects of silicon phthalocyanine photodynamic therapy.
The purpose of this study was to determine if silicon phthalocyanine 4 (Pc 4), a second-generation photosensitizer being evaluated for the photodynamic therapy (PDT) of solid tumors, was immunosuppressive. Mice treated with Pc 4 PDT 3 days before dinitrofluorobenzene sensitization showed significant suppression of their cell-mediated immune response when compared to mice that were not exposed to PDT. The response was dose dependent, required both Pc 4 and light and occurred at a skin site remote from that exposed to the laser. The immunosuppression could not be reversed by in vivo pre-treatment of mice with antibodies to tumor necrosis factor-alpha or interleukin-10. These results provide evidence that induction of cell-mediated immunity is suppressed after Pc 4 PDT. Strategies that prevent PDT-mediated immunosuppression may therefore enhance the efficacy of this therapeutic modality.
Reddan
J C
JC
Department of Otolaryngology, Case Western Reserve University, University Hospitals of Cleveland, OH, USA.
Anderson
C Y
CY
Xu
H
H
Hrabovsky
S
S
Freye
K
K
Fairchild
R
R
Tubesing
K A
KA
Elmets
C A
CA
D000818:Animals; D005260:Female; D007108:Immune Tolerance / Q000187:drug effects*; D007211:Indoles / Q000009:adverse effects / Q000627:therapeutic use*; D051379:Mice; D008809:Mice, Inbred C3H; D017646:Organosilicon Compounds / Q000009:adverse effects / Q000627:therapeutic use*; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000009:adverse effects / Q000627:therapeutic use*; D012821:Silanes
D007211:Indoles; D017646:Organosilicon Compounds; D017319:Photosensitizing Agents; D012821:Silanes; C082854:silicon phthalocyanine; C052464:bis(tri-n-hexylsiloxy)(2,3-naphthalocyaninato)silicon