Metastatic behavior of @entity1 XXXX in congenitally athymic @entity19 : intrinsic properties of the @entity5 cells and host immune reactivity.

@entity1 @entity19 @entity7433 @entity5 @entity3 @entity320
Congenitally athymic nude (nu/nu) @entity19 have been used extensively as hosts to study the metastatic properties of xenografted @entity1 @entity5 . It has not been fully explored to what extent the metastatic behavior of @entity1 @entity5 xenografts reflects the intrinsic properties of the @entity5 cells and to what extent it is influenced artificially by the host. The purpose of the work reported here was to evaluate the potential usefullness of athymic @entity19 for qualitative and quantitative assessment of the intrinsic metastatic properties of @entity1 @entity5 cells. Four @entity1 @entity320 cell lines (A-07, D-12, R-18, U-25) were included in the study. Quantitative intradermal and intracranial transplantation assays were used to determine the @entity7433 and immunogenicity of the cell lines. The metastatic behavior of the cell lines was studied by inoculating cells intra-arterially or intravenously (artificial @entity3 ) or intradermally (spontaneous @entity3 ). The influence of the host on the incidence of @entity3 was assessed by inoculating cells intravenously in immunologically modified athymic @entity19 . Both the intradermal and intracranial @entity7433 differed substantially between the cell lines. The host immune reactivity against heterotransplantation was significantly lower for D-12 than for A-07, R-18 and U-25 cells. The incidence of @entity3 was influenced significantly by the host immune reactivity. The cell lines showed organ-specific metastatic patterns in athymic @entity19 . The organs of preference were lungs for A-07 and D-12 cells, lymph nodes for R-18 cells, and brain for U-25 cells. The organ-specific metastatic pattern in athymic @entity19 reflected the pattern of distant @entity3 in the donor @entity1 . In addition, all cell lines gave rise to @entity3 in abdominal organ sites, but without organ specificity. The incidence of abdominal @entity3 was influenced significantly by the @entity7433 of the cell lines. In conclusion, athymic @entity19 appear to be excellent hosts for assessment of the organ specificity in the metastatic behavior of @entity1 @entity5 . The @entity3 frequency of @entity1 @entity5 in athymic @entity19 , however, might be a misleading quantitative measure of the intrinsic metastatic propensity of the @entity5 cells, owing to the cell-line-dependent host immune reactivity.
