Expression of isoferritins in peripheral blood lymphocytes: effect of phytohaemagglutinin and iron

This study shows that incubation of lymphocytes in phytohaemagglutinin medium together with iron supplementation leads to an increase of ferritin synthesis concomitant with increased intracellular ferritin concentration especially of heart-type ferritin. Increasing levels of iron do not increase heart-type ferritin concentration further; in contrast, spleen-type ferritin is gradually increased with increasing iron levels. The preferential increase in spleen-type ferritin on growth in iron-enriched medium may be explained by two distinct roles in the metabolism of these two isoferritins. Heart-type isoferritin appears to be involved in more active iron metabolism in lymphocytes whilst the spleen-type isoferritin may function as an intracellular depot of excess iron that is not immediately utilised for metabolic activity.