Role of CD47 as a Marker of Self on Red Blood Cells
The system recognizes invaders as foreign because they express determinants that are absent on host cells or because they lack “markers of self” that are normally present. Here we show that CD47 (integrin-associated protein) functions as a marker of self on murine red blood cells. Red blood cells that lacked CD47 were rapidly cleared from the bloodstream by splenic red pulp macrophages. CD47 on normal red blood cells prevented this elimination by binding to the inhibitory receptor signal regulatory protein alpha (SIRPα). Thus, macrophages may use variety of nonspecific activating receptors and believe the presence or absence of CD47 to differentiate self from foreign. CD47-SIRPα may represent a possible pathway for the control of haemolytic anaemia. [1]
Invasion of Red Blood Cells by Malaria Parasites
The plasmodium is that the most vital member of the Apicomplexa, an outsized and highly successful phylum of intracellular parasites. Invasion of host cells allows apicomplexan parasites access to an upscale source of nutrients during a niche that’s largely shielded from host defenses. All Apicomplexa adopt a standard mode of host-cell entry, but individual species incorporate unique features and utilize a selected set of ligand-receptor interactions. These adhesins ultimately hook up with a parasite actin-based motor, which provides the facility for invasion. While some Apicomplexa can invade many various host cells, the disease-associated blood-stage sort of the plasmodium is restricted to erythrocytes. [2]
Role of red blood cells in thrombosis
Most biomedical textbooks teach that coagulation and thrombosis are primarily a function of endothelial cells, platelets, and soluble coagulation factors. Red blood cells, in contrast, are generally considered innocent bystanders, passively entrapped during a developing thrombus as they flow through the vasculature. This review summarizes evidence that demonstrates a lively role for red cells in normal and pathologic hemostasis. We then evaluate the possible molecular mechanisms whereby a usually inert erythrocyte can actively contribute to the processes of clot formation. [3]
Plasmodium asexual growth and sexual development in the haematopoietic niche of the host
Plasmodium spp. parasites are the causative agents of malaria in humans and animals, and that they are exceptionally diverse in their morphology and life cycles. They grow and develop during a wide selection of host environments, both within blood-feeding mosquitoes, their definitive hosts, and in vertebrates, which are intermediate hosts. This diversity is testament to their exceptional adaptability and poses a serious challenge for developing effective strategies to scale back the disease burden and transmission. Following one asexual amplification cycle within the liver, parasites reach high burdens by rounds of asexual replication within red blood cells. a couple of of those blood-stage parasites make a developmental switch into the sexual stage (or gametocyte), which is important for transmission. [4]
Evaluation of the Effects of Clerodendrum polycephalum Baker Leaf Extracts on Sickle Red Blood Cells
The deathrate for people living with red blood cell disease is high and comparatively a couple of patients among them reach adult life, even with a high standard of medical aid . Clinical manifestations of the red blood cell disease are diverse and vary, falling into three major categories: anaemia, pain related issues and organ failure. red blood cell crises or painful episodes could also be caused by vessel occlusion, damaged organ, triggered by membrane deformation. Patients in West Africa , where red blood cell anaemia (SCA) is prevalent, have for ages been treated with natural products especially herbs because it remains the case in rural communities. The medicinal plant Clerodendrum polycephalum used for this study is employed ethno medically in treating malaria and pains related to red blood cell disease. [5]
Reference
[1] Oldenborg, P.A., Zheleznyak, A., Fang, Y.F., Lagenaur, C.F., Gresham, H.D. and Lindberg, F.P., 2000. Role of CD47 as a marker of self on red blood cells. Science, 288(5473), (Web Link)
[2] Cowman, A.F. and Crabb, B.S., 2006. Invasion of red blood cells by malaria parasites. Cell, 124(4), (Web Link)
[3] Andrews, D.A. and Low, P.S., 1999. Role of red blood cells in thrombosis. Current opinion in hematology, 6(2), (Web Link)
[4] Plasmodium asexual growth and sexual development in the haematopoietic niche of the host
Kannan Venugopal, Franziska Hentzschel, Gediminas Valkiūnas & Matthias Marti
Nature Reviews Microbiology (2020) (Web Link)
[5] Cyril-Olutayo, M. C., A. Adewoyin, F. and O. Ogunyemi, A. (2018) “Evaluation of the Effects of Clerodendrum polycephalum Baker Leaf Extracts on Sickle Red Blood Cells”, European Journal of Medicinal Plants, 24(1), (Web Link)