Growth and metastasis in allogeneic hosts. Lack of H-2-negative or somatic hybrid variant selection.
In vitro cultured B16 melanoma cells, which were previously found to have an impaired expression of H-2Kb and Db (as evaluated by antisera absorption assay), were used to study growth and metastasis in allogeneic mice in relation to H-2 expression. The possible emergence of somatic hybrids with host cells was also examined. B16-A cells grown subcutaneously in allogeneic BALB/c mice (H-2d) did not show a lack of H-2b expression, nor the acquirement of H-2d antigens was found. Spontaneous lung metastases were found in about 30% of BALB/c mice with progressing B16 tumor. Single lung metastases showed higher H-2b levels than cells from the respective tumors, and did not express host H-2 antigens. Tumor take was concomitant to the rise of an anti-H-2b humoral response: disease outcome was independent from the serum titer. B16-A cells injected intravenously in BALB/c mice gave rise to lung colonies; different colonies showed a wide range of H-2b antigens levels and no H-2d expression. Lung colonization capacity in normal allogeneic BALB/c mice was significantly higher than in syngeneic C57BL/6 mice. Both syngeneic and allogeneic mice, when pretreated with cyclophosphamide (CY) to reduce natural killer cell activity, showed a significant increase in lung colonization by B16-A cells. CY-treated C57BL/6 mice showed significantly higher numbers of lung colonies than CY-treated BALB/c mice. In conclusion, B16 growth and metastasis in the allogeneic environment do not seem to be determined by a selection of H-2-negative variants or by the emergence of somatic hybrids with host cells.
De Giovanni
C
C
Istituto di Cancerologia, Università di Bologna, Italia.
Lollini
P L
PL
Nicoletti
G
G
Del Re
B
B
Scotlandi
K
K
Prodi
G
G
Nanni
P
P
D000818:Animals; D006183:H-2 Antigens / Q000032:analysis*; D006239:Haplotypes; D064532:Histocompatibility Antigen H-2D; D008297:Male; D008546:Melanoma, Experimental / Q000276:immunology / Q000556:secondary; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009362:Neoplasm Metastasis / Q000276:immunology*; D009368:Neoplasm Transplantation
D006183:H-2 Antigens; C032876:H-2Kb protein, mouse; D064532:Histocompatibility Antigen H-2D