Dissimilar behavior of lymph cells in response to the action of aluminium. In vitro and in vivo studies.

In order to detect possible immunological effects of aluminum (Al) on lymph cells, mice were orally overloaded with pharmacological doses for 22 weeks. The in vitro response of lymph cells to mitogens (phytohemmaglutinin, PHA and concanavaline A, Con A) was examined at the end of the treatment. The chronic ingestion of Al affected the lymphatic nodes that were found to be 2- to 10-fold larger than those of the control mice. Concurrently, the in vitro proliferation of lymphatic node cells was found enhanced, while spleen cell cultures were unaffected. An acute direct action of Al on lymph cells from different sources was also examined. The blastogenic response to PHA of human peripheral lymphocytes was not disturbed by the presence of Al concentrations ranging from 0.09 to 900 microM. However, the response of mouse lymph cells was quite different, given that an Al dose-dependent inhibition was observed for lymphatic node cells, whereas for spleen cells the inhibition was only detected at Al concentrations higher than 90 microM. This work shows that Al might induce alterations in cell immune responses. The opposite results observed in mouse lymphatic node cells after in vitro and in vivo Al treatment, let us suggest that either the stimulating or suppressing effects of Al on the immune system might depend on the dose, route of administration and length of exposure, as well as on the cell population assayed.