Comparative Studies of Lymph Node Cell Subpopulations and Cytokine Expression in Murine Model for Testing the Potentials of Chemicals to Induce Respiratory Sensitization

Abstract

Objectives: To investigate immunological changes in lymph nodes based on expression of cell-specific receptors and cytokine expression profile and accompanying inflammatory reactions in lungs of mice treated with chemicals of known potentials to induce respiratory sensitization and those in which activity in this regard is unclear. Materials and Methods: On day 1 and 7, Balb/c mice received toluene-2,4-diisocyanate (TDI), trimellitic anhydride (TMA), 1-chloro-2,4-dinitrobenzene (DNCB), glutaraldehyde (GA), formaldehyde (FA), benzalkonium chloride (ChB) or vehicle. On day 14, they received a single intranasal instillation with the same chemical or vehicle. On day 15, auricular lymph nodes (LN) were excised and used for analyzes of T-, B-cells, expression of CD44 and for the estimation of IL-4 and IFN-γ production after in vitro stimulation with concanavalin A (ConA) and also for IL-4 and IFN-γ mRNA expression analyses using Real-Time PCR. Inflammatory changes in lungs were observed by estimation of TNF-α and MIP-2 concentrations and cell numbers and their type in BAL. Results: There were no significant changes in cell subpopulations of T helper cells in LN. The percent of B cells was significantly increased after treatment with DNCB, TDI, and GA. Increased expression of CD44 on T cells was also observed. Both IL-4 and IFN-γ were found increased in TDI-and FA-treated mice, while only IL-4 was increased in TMA-treated mice. Real-Time PCR analyses, however, showed increased IL-4 mRNA expression for TDI-and TMA-, and IFN-γ mRNA expression for DNCB-treated mice. We haven't observed significant changes in inflammatory reactions in the lungs of exposed animals. Conclusions: Studying immunological changes with first determining the activation status of T cells followed by analyzes of expression of mRNA for Th1 and Th2 cytokines in murine model could be a useful method for assessment of the potentials of chemicals to induce respiratory sensitization but is not sufficient. Addition of ventilatory measurements, but not necessarily inflammatory reactions, could complete the model.

Effects of Formaldehyde on Lymphocyte Subsets and Cytokines in the Peripheral Blood of Exposed Workers

“…IL-4 directly induces the differentiation of T cells into the committed effector Th2 lymphocytes [36]. Our findings of the increased serum levels of IL-4 in FA-exposed workers concur with previous reports that there was an increased IL-4 release in FA-treated mice [18], [19].…”

“…Some studies have attempted to evaluate the impact of FA on different types of blood cells and soluble mediators such as cytokines and chemokines [10], [12], [16], [18], [19]. These studies were inconsistent and had limited information on lymphocyte composition and profiles of the Th1 and Th2 cytokines in FA-exposed workers.…”

Aberrant Production of Th1/Th2/Th17-Related Cytokines in Serum of C57BL/6 Mice after Short-Term Formaldehyde Exposure

“…To determine the immunotoxicity of FA exposure, cell-mediated immunity and humoral immunity were investigated in vivo and in vitro [ 2 , 10 , 20 , 37 , 38 , 39 ]. Cytokines play a pivotal role in the induction of cell-mediated immunity and humoral immunity.…”