EVALUATION OF DATA FROM MITOGEN STUDIES IN CBA MICE - COMPARISON OF COUNTS PER MINUTE, STIMULATION INDEX AND RELATIVE PROLIFERATION INDEX

Abstract

Lymphocyte proliferation assays were conducted on splenic lymphocytes collected from CBA mice that were exposed to lead acetate or cadmium chloride for 10 wk. The ability of mitogens concanavalin A and lipopolysaccharide and purified protein derivative to induce proliferation in vitro in the presence or absence of macrophages was assessed. Data were compared by using cpm, stimulation index and relative proliferative index. Data varied considerably within treatment groups performed on different days, which is a typical characteristic of mitogen proliferation investigations. According to cpm data, only 3 of 21 treatments were significantly (P < 0.05) altered when compared with controls. The stimulation indices were highly influenced by background counts and frequently did not correlate with cpm. The relative proliferative index calculates net cpm, closely corresponds to cpm, compensates for background counts and is affected less by variation than is the stimulation index and selected cutoff values give a more sensitive measure for determination of altered proliferative responses when statistical procedures are not applicable. Effects of macrophages, CO2 and bovine fetal serum on lymphocyte transformation were discussed.