Echinococcus granulosus: assays for hydatid immunoregulatory factors using established lymphoid cell lines

Mitosis, mitochondrial metabolic rate and proliferation were measured in established lymphoid cell lines exposed to chromatographic fractions of equine Echinococcus granulosus hydatid fluid. In several cell lines, one or more of the three parameters were modified by the exposure. As an assay for potential immunoregulatory activity, the method was simple and repeatable. The following novel observations were made: (1) Mitotic reaction was found among lines of T-cell, B-cell and macrophage origin; (2) mitosis was accompanied by proliferation in the B-cell lines, B9 and A20, and in the macrophage lines, HL-60 and P388d. With mitotically responsive T-cells, proliferation was slight in CTLL-2 and absent in D10, implying cell-cycle modification; (3) mitotic responsiveness tended to occur in cell lines with mature characteristics; (4) among cytokine-dependent cell lines, hydatid fluid FPLC fraction 1 mimicked IL-1 and several fractions mimicked IL-2 and IL-6 in the maintenance of mitosis; and (5) there was significant statistical interaction between the influences of mammalian cytokines and hydatid fluid fractions, implying that the propensity of antigenically unprimed lymphoid cells to be regulated by E. granulosus is conditioned by cytokine activity.