Bacillus Calmette-Guérin cell-wall skeleton enhances the killing activity of cytotoxic lymphocyte-activated human dendritic cells transduced with the prostate-specific antigen gene.
To determine whether dendritic cells (DC) transduced with the prostate-specific antigen (PSA) gene can induce PSA-specific cytotoxic lymphocytes (CTL) against prostate cancer cells, and whether bacillus Calmette-Guérin (BCG) cell-wall skeleton (CWS) can enhance the maturation of DC-PSA and the killing activity of subsequently induced PSA-specific CTL. MATERIALS AND METHODS; We generated an adenovirus encoding the PSA gene (AxCA-PSA) using the cosmid-terminal protein complex method. DC were infected with AxCA-PSA using the centrifugal method. The ability of CTL to lyse target cells expressing PSA, i.e the PSA-positive prostate cancer cell line, LNCap, and PSA-transduced autologous phytohaemagglutinin (PHA) blasts expressing PSA, was assessed using the 51Cr-release assay. The maturation of DC-PSA stimulated by BCG-CWS was assayed by flow cytometry. The cytotoxic activity enhanced by BCG-CWS was assessed by the 51Cr-release assay.


RESULTS
DC-PSA induced PSA-specific CTL with 85% cytotoxic activity against LNCaP (effector: target ratio, E:T, of 50:1). However, the cytotoxic activity against PSA-negative cells was very low. Anti-CD8 and anti-major histocompatibility (MHC) class I antibodies blocked PSA-specific cytotoxicity. The PSA-specific killing was reproducible against autologous PHA blast cells expressing PSA, independently of human leukocyte antigen haplotype. Furthermore, the combination of DC-PSA with BCG-CWS remarkably enhanced the PSA-specific cytotoxicity against PHA blasts expressing PSA (15-30% at an E:T ratio of 50:1).


CONCLUSIONS
These findings suggest that DC-PSA can induce MHC class I-restricted PSA-specific CD8+ CTL responses and that DC-PSA matured by BCG-CWS enhance PSA-specific cytotoxicity. The combination of DC-PSA with BCG-CWS might be a useful approach for treating advanced prostate cancer.
Fujii
Reona
R
Departments of Urology, Wakayama Medical University, Wakayama, Japan.
Iwahashi
Makoto
M
Kikkawa
Kazuro
K
Inagaki
Takeshi
T
Kohjimoto
Yasuo
Y
Ojima
Toshiyasu
T
Mori
Takashi
T
Kuramoto
Tomomi
T
Nishizawa
Satoshi
S
Azuma
Ichiro
I
Yamaue
Hiroki
H
Shinka
Toshiaki
T
Hara
Isao
I
D000256:Adenoviridae / Q000235:genetics; D016827:CD8 Antigens / Q000276:immunology; D045744:Cell Line, Tumor; D017358:Cell Wall Skeleton / Q000276:immunology / Q000494:pharmacology*; D003713:Dendritic Cells / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D015316:Genetic Therapy / Q000379:methods; D005822:Genetic Vectors; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D006801:Humans; D007167:Immunotherapy / Q000379:methods; D008297:Male; D009163:Mycobacterium bovis; D017430:Prostate-Specific Antigen / Q000235:genetics*; D011471:Prostatic Neoplasms / Q000628:therapy*; D013602:T-Lymphocytes, Cytotoxic / Q000502:physiology*; D014161:Transduction, Genetic
D016827:CD8 Antigens; D017358:Cell Wall Skeleton; D015395:Histocompatibility Antigens Class I; D017430:Prostate-Specific Antigen