Figure 1.

Growth of wt, IL-1α^-/-, IL-1β^-/-, and IL-1αβ^-/- fibrosarcoma lines in nu/nu mice. (A and B) nu/nu mice (10 mice/line) received a s.c. injection of 5 x 10⁵ fibrosarcoma cells from 3 wt, IL-1α^-/-, IL-1β^-/-, and IL-1αβ^-/- fibrosarcoma lines. (A) Starting 7 days after tumor cell inoculation, tumor growth was monitored twice per week by measuring the tumor diameter. The mean tumor diameter ± SD of 30 mice/group (10 mice/line) is shown. (B) Mice were sacrificed when the mean tumor diameter reached 3 cm (survival time). The mean survival time ± SD (30 mice/group; 10 mice/line) is shown. Significant differences in the mean tumor diameter and the survival time as compared to mice receiving wt clones are indicated by an asterisk. (C and D) Wt, IL-1α^-/-, IL-1β^-/-, and IL-1αβ^-/- fibrosarcoma cells (5 x 10⁵) were s.c. implanted into nu/nu mice. Tumors of a mean diameter of 0.5 cm were excised, shock frozen and 5 µm sections were stained with anti-Gr-1 (C) and anti-CD31 (D). Representative examples of one wt, IL-1α^-/-, IL-1β^-/-, and IL-1αβ^-/- fibrosarcoma lines are shown. (E) IL-1α, IL-1β, and IL-1Ra expression and secretion was evaluated in lysates (corresponding to 1 x 10⁵ cells) and culture supernatants (fresh medium being added to subconfluent cultures and being collected after 24 hours) of wt, IL-1α^-/-, IL-1β^-/-, IL-1αβ^-/-, and IL-1RI^-/- fibrosarcoma lines by ELISA. Secreted IL-1α hardly could be detected in any of the tested lines. Yet, even in supernatants and lysates of IL-1^wt and IL-1RI^-/- cells, IL-1α and IL-1β was too low for a reliable quantification. Therefore, extinction values (mean ± SD of triplicates) are shown. Background values have been subtracted.