Effect of hepatic isoferritins from iron overloaded rats on lymphocyte proliferative response: role of ferritin iron content.

The research explored and confirmed the role of iron and ferritin, especially the latter’s iron content, in impairing immune response by inhibiting lymphocyte proliferation, potentially giving rise to the understanding of ferritin as an immunosuppressor.

Objective and Methodology

• The purpose for conducting this research was to understand how the iron content in ferritin impacts the proliferative response of rat lymphocytes, a crucial part of the immune system.
• Isoferritins, differing in their iron content and isoelectric point (pI), were isolated from rat livers dealing with iron overload using ultracentrifugation and crystallization methods.
• Commercial horse splenic ferritin was utilized for comparison due to its differences in pI and iron content.

Findings

• When spleen cells were exposed to rat and horse isoferritins during testing, the lymphocyte proliferative response decreased in a dose-dependent manner.
• The isoferritins with higher iron content (those obtained through ultracentrifugation and horse ferritin) caused a more significant decrease in the proliferative response.
• When devoid of iron, both rat and horse ferritins (apoferritins) did not inhibit lymphocyte proliferation, indicating that the inhibitory effect is likely due to iron.
• It was hypothesized that the inhibitory effect might also be due to the reactive oxygen species resulting from the iron released by the isoferritins, which may negatively affect lymphocyte functions.

Perspective of In vivo Immunomodulatory Role of Ferritin

• The study also considered the influence of serum ferritin levels on the proliferative response in a model of iron overload in rats.
• An inverse relationship was noted between the proliferative response and serum ferritin levels, suggesting high levels of serum ferritin might suppress the immune response.
• The research concluded that the lymphocyte proliferative response inhibition brought about by isoferritins is primarily due to the protein’s iron content and not solely due to variations in pI. This falls in line with the hypothesis of ferritin potentially playing an suppressive role in the immune response.