Induction of T-cell-mediated immunity against MethA fibrosarcoma by intratumoral injections of a bacillus Calmette-Guérin nucleic acid fraction.
MY-1, which consists of DNA and RNA extracted and purified from bacillus Calmette-Guérin (BCG), has been shown to have strong antitumor activity against various experimental tumors. To examine the role of T cells in the antitumor mechanism of MY-1, the effect of MY-1 injection on the development of tumor-specific immunity against MethA fibrosarcoma was investigated. MY-1 injections inhibited tumor growth less effectively in T-cell-deficient nude mice than in normal BALB/c mice. MethA tumor growth was suppressed after inoculation with L3T4-positive lymphocytes from tumor-bearing mice treated with MY-1. MethA-specific delayed-type hypersensitivity was also detected in tumor-bearing mice treated with MY-1. Immunohistochemical analyses showed that many L3T4-positive and a few Lyt2-positive cells infiltrated the regressing tumors. These results indicate that intratumoral MY-1 injections induce a MethA-specific, L3T4-positive cell-mediated, delayed-type hypersensitivity, which is necessary for the tumor regression.
Institute of Biological Science, Mitsui Pharmaceuticals, Inc., Chiba, Japan.
E
E
Kuramoto
O
O
Yano
S
S
Shimada
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D004269:DNA, Bacterial / Q000008:administration & dosage* / Q000627:therapeutic use; D005260:Female; D005354:Fibrosarcoma / Q000139:chemically induced / Q000276:immunology / Q000628:therapy*; D007111:Immunity, Cellular; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009163:Mycobacterium bovis; D009368:Neoplasm Transplantation / Q000276:immunology; D012329:RNA, Bacterial / Q000008:administration & dosage* / Q000627:therapeutic use; D012513:Sarcoma, Experimental / Q000139:chemically induced; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000276:immunology*
D000945:Antigens, Differentiation, T-Lymphocyte; D004269:DNA, Bacterial; D012329:RNA, Bacterial