Hi, in one of my Labs we conducted a mitogenesis assay on a splenocyte sample using Concanavalin A and Lipopolysacharride as our lectins/mitogens. Different concentrations of mitogen were added to the cell suspension and the plated suspensions were measured for absorbance to measure splenocyte/lymphocyte proliferation.

When I drew curves for the two lectins, plotting concentration against absorbance, they were roughly ( very roughly ) a bell shape. With absorbance ( cell proliferation ) rising with concentration to a certain point and then falling past that point.

Can anyone tell me why this happens, i.e Why does cell proliferation fall after mitogen concentration rises above a certain point? I have searched the literature but have not been able to find an answer.

I have read in a paper that mitogens/lectins can be toxic, so my current theory is that past a certain concentration the mitogen becomes toxic to the cell culture and prevents/inhibits proliferation. Am i on the right lines?? Please link papers/sources.
Sorry for the long post, thanks.