Thiabendazole (TBZ), an immunohemomodulator. I. Effects on lymph node and spleen.

Previous studies in our laboratory with Thiabendazole (TBZ) indicated that the drug significantly augmented cellular immune responses in mice. The purpose of the present and companion study was to determine which of the cell populations in primary and secondary lymphoid organs and in bone marrow were affected by the in-vivo administration of TBZ. Two major changes in lymph nodes and/or spleens of TBZ-treated mice were detected by histological and quantitative planimetric analysis: (1) expansion of T and B lymphocyte compartments and (2) increase in extramedullary hemopoiesis. The effect on T cells and on hemopoiesis were observed only when TBZ was administered with the thymus-dependent neoantigen, dinitrofluorobenzene (DNFB). The effect on B cells appeared to be antigen-independent. Increased extramedullary hemopoiesis in TBZ + DNFB-treated mice was preceded by a significant increase in pluripotent hemopoietic stem cell activity in bone marrow, as measured by the CFU-S assay. This study indicates that TBZ has significant effects on the development and differentiation of both lymphoid and hemopoietic cells.