Article Figures & Data
Figures
- Fig. 1.
Metastasis in NK-depleted mice. Mice received TM-β1 i.p. to deplete NK cells 1 week before the i.v. injection of CFS1 (1 × 105), B16 (1 × 105), or ESb (2 × 105) tumor cells. The number of micrometastases per mm2 was quantified on stained lung sections for CFS1 or on liver sections for ESb tumor cells 4 days after tumor cell injection. Surface metastases were counted on lungs on day 10 after B16 tumor cell injection. The results are given as means; bars, SD.
- Fig. 2.
Platelet-specific staining of tumor cells after coculture with platelets. Tumor cells were stained with the fluoresceinated monoclonal rat anti-mouse CD41 (fibrinogen receptor, gpIIb/IIIa) antibody (MWReg30, 5 μg/105 tumor cells/ml). A, in the cytofluorometric analysis, the shaded area represents nonspecific background staining of the CFS1, B16, or ESb tumor cells with MWReg30. Positive staining with MWReg30 was found when platelets (1000 platelets/tumor cell) were added to CFS1 and B16 tumor cells. B, microscopic analysis of a coculture of platelets with CFS1 tumor cells (1000 platelets/tumor cell; left, phase contrast; right, fluorescence microscopy; ×400).
- Fig. 3.
Metastasis in thrombocytopenic mice. Mice had received either rabbit anti-mouse platelet serum or control rabbit serum (100 μl) i.p. 24 h before the i.v. injection of CFS1 (1 × 105), B16 (1 × 105), or ESb (2 × 105) tumor cells. The number of micrometastases per mm2 was quantified on stained lung sections for CFS1 or on liver sections for ESb tumor cells 4 days after tumor cell injection. Surface metastases were counted on lungs on day 10 after B16 tumor cell injection. The results are given as means; bars, SD.
- Fig. 4.
Metastasis in thrombocytopenic mice after NK cell depletion. Mice had received either TM-β1 or control rat immunoglobulin (1 mg in 100 μl PBS) i.p. 1 week before and either rabbit anti-mouse platelet serum or control rabbit serum (100 μl) i.p. 24 h before the i.v. injection of CFS1 (1 × 106 in normal and 5 × 105 in TM-β1-treated mice), B16 (1 × 105), or ESb (2 × 105) tumor cells. The number of micrometastases per mm2 was quantified on stained lung sections for CFS1 or on liver sections for ESb tumor cells 4 days after tumor cell injection. Surface metastases were counted on lungs on day 10 after B16 tumor cell injection. The results are given as means; bars, SD.
- Fig. 5.
Inhibition of splenic NK activity by the addition of platelets. Lytic activity of spleen cell suspensions in the absence (•) or presence of 1,000 (▪) or 10,000 (▴) platelets per YAC1 target cell was determined in a 4-h 51Cr-release NK assay (spontaneous release, 4.9%). Bars, SD.
Tables
- Table 1
Effect of NK cell depletion and platelet depletion on lung metastasis
Numbers of micrometastases and percentage of inoculated tumor cells were assessed based on counted tumor lung colonies, thickness of tissue sections, and lung volume. NK cells Platelets Inoculated tumor cells Micrometastases per % of inoculated tumor cells mm2 mm3 Lung Present Present 1 × 106 8 160 5.5 × 104 5.5 Present Absent 1 × 106 0.4 8 2.8 × 103 0.3 Absent Present 3 × 104 4 80 2.8 × 104 93 Absent Absent 3 × 104 4 80 2.8 × 104 93 - Table 2
Inhibition of NK activity by the addition of platelets
The inhibitory capacity of platelets from mice of different strains and the influence of aggregation inhibitors hirudin (1 unit/ml), heparin (1 unit/ml), apyrase (5 units/ml), anti-P-selectin MAb (10 μg/ml), 2-h platelet supernatant, or 2-h platelet + YAC1 supernatant were determined in a 4-h 51Cr-release NK assay using C3H/HeN spleen cells as source of NK cells. The data given were obtained with an E:T ratio of 100:1 and in the presence of 10,000 platelets per YAC1 tumor cell. Specific lysis without the addition of platelets or inhibitors was 36.6 ± 1.2% in A, 46.5 ± 1.1% in B, and 11.6 ± 0.4 in C. Platelet donor mouse strain Added substance Inhibition of specific lysis % A − − 0 C3H/HeN − 54.7 ± 4.5 C57BI/6 − 56.1 ± 1.1 C57BI/6/SVJ129 − 53.8 ± 2.5 NMRI − 64.2 ± 0.8 β2-Microglobulin−/− − 46.6 ± 2.4 B C3H/HeN Hirudin 0.5 ± 4.4 C3H/HeN Heparin 41.3 ± 3.2 C3H/HeN Apyrase 38.1 ± 4.3 C3H/HeN Anti-P-selectin 36.0 ± 4.5 C3H/HeN Rat IgG 65.8 ± 7.0 C − − 0 C3H/HeN − 77.4 ± 4.6 − Platelet supernatant 32.8 ± 5.2 − Platelet + YAC1 Supernatant 30.4 ± 4.8
Volume 59, Issue 6
