The Use of Kernel Estimators in Describing Human T Lymphocyte Proliferation Induced by Phorbol Esters and Ca2+ Ionophore

Publisher Website
Google Scholar
Abstract
A nonparametric method for analyzing the mitogenic count data generated from in vitro T cell stimulation by phorbol dibutyrate (PDBu) and ionomycin (I) is described. Antigen receptor initiated T cell activation is transduced by the combined second messenger actions of phospholipid metabolites diacylglycerol (DAG) and inositol triphosphate (IP3). DAG activates protein kinase C, and IP3 serves to elevate cytosolic Ca2+ levels. Pharmacological agents, such as phorbol esters and the Ca2+ ionophore ionomycin, mimic DAG and IP3, respectively. Consequently, they can be used to initiate T lymphocyte activation and subsequent proliferation. Given mitogenic count data measured by 3H-thymidine incorporation, a kernel estimate of the proliferative response surface is used to develop a confidence region for the optimal combination level of PDBu and ionomycin for maximum T cell proliferation. The experimental data analysis was validated with a small computer simulation study. The resulting confidence regions have high coverage probabilites robust with respect to the shape of the underlying proliferative response surface. This bias robustness is important in this application because the shape of the response surface may vary among individuals. Thus, this procedure will allow for optimization of an individual's T cell proliferative response.