Question

An investigator has treated a number of cell lines with IL-45 (10 ng/ml), a newly discovered inhibitory cytokine and then evaluated the cell growth behaviours of these cells following 6, 24, 48 and 72 hours of incubation respectively, in vitro. The results were: KG-2 cells (macrophages) exhibited decreased growth. JM-1 cells (lymphoblasts from B-cell lymphoma) exhibited increased growth. NK-92 cells exhibited no alterations.

Question: Explain the growth behaviours exhibited by these 3 cell lines in vitro. (what research questions will you investigate, what are the mechanisms involved, what tests will you do, approaches, experiments, studies, etc.)

Answer 1

KG-2 cells (macrophages) exhibited decreased growth. This means that IL-45 (10 ng/ml) has inhibitory effect on macrophages.

JM-1 cells (lymphoblast from B-cell lymphoma) exhibited increased growth. This shows that IL-45 (10 ng/ml) has enhanced effect on lL-45 (10 ng/ml)

NK-92 cells exhibited no alterations. This shows that 10 ng/ml of IL-45 is not enough to show any kind of effect. Further higher dose of the cytokine should.be tested on NK-92 cells to trace any kind of inhibition or excitation.

Research questions which should be investigated ?

• What is the exact dose of IL-45 which produces inhibitory or excitory effects on each of the three cell lines?
• What MHCs does IL-45 invade?

Mechanism involved

Cytokines act by means of cytokine receptors. When cytokine binds to cytokine receptor on the effector cell, it induces downstream signal transduction cascades. Then other receptors are activated. These can be glutamate receptors, vanilloid receptors, or sodium channels.

So, the mode of action of IL-45 on these three cell lines will involve a study of receptors which are activated on the target cells (KG-2 cells, NK-92 cells, JM-1 cells) on reaction with IL-45.

Inflammatory tests which are specific for cytokines should be performed.