In vivo immunogenicity of osteosarcoma cells that express B7-1a, an alternatively spliced form of B7-1.
BACKGROUND
B7 family members play a central costimulatory role in T cell activation. We have previously identified B7-1a, an alternatively spliced form of B7-1. The function of B7-1a in induction of anti-tumor immunity remains uncertain.


METHODS
The cDNAs of murine B7-1, B7-1a and B7-2 were introduced into a murine osteosarcoma cell line, LM8. The ability of B7 transfectants to elicit in vivo anti-tumor immunity was comparatively analyzed with respect to tumorigenecity, pulmonary metastasis and survival time.


RESULTS
LM8 cells expressing B7-1, B7-1a, or B7-2 all elicited immunological responses in immunocompetent C3H/He mice. Notably, the anti-tumor effects were most obvious in mice inoculated with B7-1a-transfected LM8 cells. Such a difference among B7-transfectants became indistinguishable in immunodeficient nude mice.


CONCLUSIONS
These findings indicate that B7-1a serves as a more efficacious costimulatory molecule than B7-1 or B7-2 in the induction and maintenance of anti-tumor immune responses against a poorly immunogenic osteosarcoma cell line.
Nagamori
Masashi
M
Department of Orthopedic Surgery, Sapporo Medical University School of Medicine, Japan.
Kawaguchi
Satoshi
S
Murakami
Masaaki
M
Wada
Takuro
T
Inobe
Manabu
M
Ishii
Seiichi
S
Uede
Toshimitsu
T
D017398:Alternative Splicing; D000818:Animals; D015703:Antigens, CD / Q000235:genetics; D018122:B7-1 Antigen / Q000235:genetics*; D001859:Bone Neoplasms / Q000235:genetics / Q000276:immunology / Q000401:mortality; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D008285:Major Histocompatibility Complex; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D012516:Osteosarcoma / Q000235:genetics* / Q000276:immunology* / Q000401:mortality; D015996:Survival Rate; D014162:Transfection; D014407:Tumor Cells, Cultured
D015703:Antigens, CD; D018122:B7-1 Antigen; D015395:Histocompatibility Antigens Class I