Different T-cell activation by streptozotocin and Freund's adjuvant in popliteal lymph node (PLN).

A popliteal lymph node (PLN) test was further validated for predictive screening of autoimmunity-inducing drugs. Autoimmune-like T-cell activation of streptozotocin (STZ) was compared with the effect of Freund's complete adjuvant (FCA), injected locally into the foot pad of BALB/c mice. Early cell activation in enlarged PLN was monitored by flow cytometry. Injection of both STZ and FCA markedly increased the absolute PLN cell number as well as specific T-helper (CD4+), T-suppressor/cytotoxic (CD8+), and B (Ig+) subsets. However, quantitative analysis of early T-cell activation revealed important differences between STZ-induced PLN reaction and FCA-related lymphoproliferation. At 72 h, the number of cells stained with anti-early activation marker (EAM+; CD69+) increased over 10 times in STZ-enlarged nodes and only 3 times in the FCA-inflamed nodes. Furthermore, different cytometric profiles were noted for STZ-activated and FCA-activated cells stained with anti-interleukin-2 receptor (IL-2R) (CD25+). The data suggest the applicability of early cytometric screening of enlarged PLN for predictive analysis detection of chemicals inducing an autoimmune-like reaction.