title: In vivo acquired mechanisms of tumor cells local defense against the host innate immunity effectors: implication in specific antitumor immunity.
abstract: As shown earlier, the cells transformed in vitro by several different oncogenes, or spontaneously, during in vivo growth in normal hosts would be gradually replaced by the highly-tumorigenic descendants co-expressing high H2O2-catabolizing and PGE2-releasing activities. Acquisition of (H2O2(CA) + PGE(S)) phenotype provides the cells with local defense mechanisms against the host innate immunity effectors. However, it remained unknown, whether the expression of (H2O2(CA) + PGE(S)) phenotype is implicated in susceptibility of tumor cells expressing tumor-specific transplantation antigens to rejection in immune animals. Here, with the use of SV40 in vitro transformed parental cells, negative in expression (H2O2(CA) + PGE(S)) phenotype, and their in vivo selected descendant tumor cell lines expressing this phenotype, we show that: (1) the rates of in vivo selection of the parental SV40 tumor cells expressing (H2O2(CA) + PGE(S)) phenotype are the same in normal and SV40-immune animals; (2) in vivo selected SV40 tumor cells expressing (H2O2(CA) + PGE(S)) phenotype, although they retain specific immunosensitivity, are 100 times less effectively rejected in SV40-immunized animals, as compared with their in vitro SV40-transformed parental cells. Thus, in vivo acquired immunologically non-specific local mechanisms of tumor cells defense against the host innate immunity effectors, significantly decreases the effectiveness of their specific immunorejection.
authors.affiliation: Laboratory of Antitumor Immunity, Institute of Carcinogenesis, N.N. Blokchin Cancer Research Center, Russian Academy of Medical Sciences, Moscow. antitum@iki.rssi.ru
authors.forename: G
authors.initials: G
authors.lastname: Deichman
authors.forename: N
authors.initials: N
authors.lastname: Dyakova
authors.forename: L
authors.initials: L
authors.lastname: Kashkina
authors.forename: V
authors.initials: V
authors.lastname: Matveeva
authors.forename: E
authors.initials: E
authors.lastname: Uvarova
mesh_terms: D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000276:immunology; D000975:Antioxidants / Q000378:metabolism*; D002461:Cell Line, Transformed; D002472:Cell Transformation, Viral; D006224:Cricetinae; D015232:Dinoprostone / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D007113:Immunity, Innate; D009361:Neoplasm Invasiveness; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000276:immunology*; D010641:Phenotype
chemical_list: D000952:Antigens, Polyomavirus Transforming; D000975:Antioxidants; D006861:Hydrogen Peroxide; D015232:Dinoprostone