Circulating immune complexes in rats with metastasizing or nonmetastasizing mammary tumor.

The dual rat metastatic and nonmetastatic mammary tumor model was characterized by the level of immune complexes in the sera of rats bearing these tumors. Circulating immune complexes (CIC) were measured at various intervals posttumor injection in Wistar-Furth (W/Fu) rats inoculated at 2 months of age with either 1 X 10(6) viable metastasizing (TMT-081) or nonmetastasizing (MT-100) tumor cells into the mammary fat pads. The Raji cell assay was used to measure CIC. No correlation between tumor size and CIC levels in the tumors were observed. While none of the sera from the rats bearing the nonmetastasizing tumors had CIC levels higher than 30 micrograms/ml, a small percentage of the animals bearing the metastasizing tumors had serum CIC levels higher than 30 micrograms/ml. This study suggests no clear difference between the amount of CIC in the sera of animals bearing either metastasizing or nonmetastasizing tumors.