CELL-SURFACE ANTIGENS IN A RAT COLON CANCER MODEL - CORRELATION WITH INHIBITION OF TUMOR-GROWTH

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  • 1 January 1977
    • journal article
    • research article
    • Vol. 82  (1) , 164-169
Abstract
Chemically induced bowel tumors in Wistar/Furth (W/F) rats possess surface antigens analogous to those demonstrated in humans with colon carcinoma. To determine if these in vitro tumor markers have any in vivo significance, tumor isograft challenge experiments were performed. Groups of animals received 3 immunizing doses of 107 cells from chemically induced colon carcinomas NG-W1, DMH-W49 or DMH-W9, or small bowel adenocarcinoma DMH-W7. Control rats were immunized with a noncross reacting, virally induced mammary fibroadenoma A9-W1. Six weeks after immunization, all animals wer challenged with 1 .times. 105 or 3 .times. 104 colon carcinoma NG-W1 cells. None of the NG-W1 immunized animals developed tumors after NG-W1 challenge dose. In contrast to this strong protection private tumor rejection antigen (TRA), protection by common or tissue type specific antigens was evident only if tumor volumes were measured. Twenty-two days after low dose NG-W1 challenge, mean tumor volume (m) in animals immunized with colon tumor DMH-W9 (m = 0.25 cm3) and DMH-W49 (m = 0.17 cm3) were less (P < 0.05) than in animals untreated (m = 1.0 cm3) or immunized with mammary fibroadenoma A9-W1 (m = 0.9 cm3). Embryonic antigens also may function as weak TRA. NG-W1 challenge tumor volumes in fetal gut immunized (m = 0.9 cm3) and whole embryo immunized animals (m = 0.9 cm3) were less (P < 0.05) than in fetal kidney immunized (m = 2.5 cm3) or adult colon immunized animals (m = 1.8 cm3). Low dose NG-W1 challenge tumor volumes were less (P < 0.01) in multiparous females (m = 0.3 cm3) than in untreated (m = 1.2 cm3) or age matched virgins (m = 1.4 cm3). In vitro tumor markers in this model may serve an important function in vivo as TRA.