Role of Immature Red Blood Cells in Neonatal Immunity

Newborns are highly susceptible to diseases. Infections such as Bordetella Pertussis (i.e. whooping cough) and Listeria (i.e. food poisoning) can result in the death of neonates while causing little harm to older children and adults. Although previously attributed to an underdeveloped immune system, recent research has shown that this susceptibility is due to the high presence of immature red blood cells or CD71+ cells. These cells possess immunosuppressive properties. By interfering with the function of other immune cells, they can prevent an effective pathogenic immune response. In this study, the changes in the amount of CD71+ cells were observed throughout the different age points of mice as well as in mice infected with Bordetella pertussis and Listeria. This study aimed to gain a better understanding of the development of the immune system as to better aid neonates in fighting infection. Flow cytometry was used to determine the amount of CD71+ cells in the spleens of mice at different age points. The results showed that overall the amount of CD71+ cells decreased as the age of the mouse increased, paralleling the decrease in susceptibility of the immune system. Furthermore, the change in CD71+ cells was also observed in the spleens of mice infected with Bordetella pertussis and mice infected with Listeria. There was no significant change for the Listeria infected mice, as CD71+ cells play no immunological role in fighting Listeria, an intracellular bacteria. However, there was a significant increase in CD71+ cells in Bordetella Pertussis infected mice since this infection was extracellular. These results show that CD71+ cells react differently to different infections and play a different immunological role in the presence of different pathogens. Furthermore, the results shows a direct correlation between age and the amount of CD71+ cells present in the spleen. The changes in the amount of CD71+ cells was most likely due to different pathological conditions and requirements at different ages