Thermochimica Acta, 241 (1994) 87-94 Elsevier Science B.V., Amsterdam SSDZ 0040-603 1( 94)01677-9 87 Human schistosomiasis: evaluation of the reactivity of peripheral blood mononuclear cells by calorimetry M.M. Chaves, F.C. Lima e Silva, M. Mares-Guia and J.A. Nogueira-Machado * Departamento de Bioquimica-Zmunologia, Znstituto de Cikias Biolbgicas and Faculdade de Medicina, Universidade Federal de Minas Gerais, C. Postal 486, 30161-970 Belo Horizonte MG, Brazil (Received 28 May 1993; accepted 17 December 1993) zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQP Abstract Peripheral blood mononuclear cells (PBMN) from Schistosoma mansoni-infected patients were exposed in a calorimeter to soluble adult worm antigenic preparation (SWAP), phytohemaglutinin (PHA), 4-P-phorbol-12,13-dibutyrate (PDB) or interferon-y (IFN-y) - enriched supernatant obtained after calorimetric experiment. The total heat released by antigen-stimulated PBMN from infected patients was significantly higher than that produced by PBMN from normal subjects stimulated with the same antigen. Antigen-induced, cell-free supernatants obtained after calorimetric experiments were able to elicit in PBMN from normal subjects a heat release pattern similar to that seen with S. mansoni-infected cells. This activating effect, however, was fully removed by pre-incubation of the supernatant with monoclonal antibodies against IFN-y. The discrimination between PBMN from infected patients and normal subjects was also made possible by evaluation of the cell reactivity under stimulation with either PHA or PDB. Our results demonstrate that, due to its high sensitivity, calorimetry may become an important tool for basic immunological studies. INTRODUCTION In the last two decades, calorimetry has been shown to be a highly sensitive technique for assessing lymphocyte function. It is a convenient method for estimating the metabolic status of human blood cells and has often been used as an important tool in physiological and pathological studies of cell biology. A significant increase in the heat production was noted in human leukocytes under stimulation with mitogen [ 1,2], immune complex [3] or during phagocytosis [4]. In cells from diseased patients, alterations in the heat production by lymphocytes from non-Hodgkins lymphoma, chronic * Corresponding author. 0040-6031/94/$07.00 0 1994 - Elsevier Science B.V. All rights reserved