When investigating the effect of co-culturing NK cells with eosinophils for up to 12 hours, researchers chose to co-culture all samples in the presence of interleukin-5, a cytokine.
What is the most likely reason for this decision?

A. Interleukin-5 facilitates degranulation in NK cells.
B. Interleukin-5 inhibits the cytotoxic effects that NK cells have against eosinophils.
C. Eosinophils die rapidly when not exposed to interleukin-5.
D. The researchers were directly testing the effect of interleukin-5 on eosinophil activity.

Eosinophil is immune system inflammatory cells which kills bacteria and other virulent material and do inflammation by releasing inflammatory mediators like cytokine. And for removing these dead cells NK cells do apoptosis of the cell for preventing tissue damage. And for preventing the destruction of eosinophilic cell interlukin-5 is used in this process.

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