What is marginal zone?
The marginal zone is where the distribution of blood flow between slow and fast transit pathways is controlled. The slow pathways permit prolonged exposure of blood cells and particles to phagocytic cells.
What are marginal zone cells?
Marginal zone (MZ) B cells comprise a subset of innate-like B cells found predominantly in the spleen, but also in lymph nodes and blood. Their principal functions are participation in quick responses to blood-borne pathogens and secretion of natural antibodies.
What cells are in the marginal zone of the spleen?
The marginal zone is described as a layer surrounding the periarteriolar lymphocyte sheath (PALS) and B cell follicles, predominantly composed of intermediate-sized lymphocytes.
Why is it called white pulp?
White pulp is a histological designation for regions of the spleen (named because it appears whiter than the surrounding red pulp on gross section), that encompasses approximately 25% of splenic tissue. White pulp consists entirely of lymphoid tissue.
What is the function of marginal zone?
Function. The major role of marginal zone is to trap particulate antigen from the circulation and present the antigen to the lymphocytes of the spleen. Experiments have shown that inert latex beads as well as live bacteria such as Escherichia coli and Listeria monocytogenes are trapped by the marginal zone.
What does MZL stand for?
Marginal zone lymphoma (MZL) is a group of indolent (slow growing) NHL B-cell lymphomas, which account for approximately eight percent of all NHL cases.
What is a marginal zone B cell?
Key Points. Marginal zone (MZ) B cells are strategically located at the interface between the circulation and the white pulp of the spleen, where they provide a first line of defence by rapidly producing IgM and class-switched IgG antibodies in response to infections by blood-borne viruses and encapsulated bacteria.
Do marginal zone B cells express IgD?
In contrast to follicular B cells, marginal zone B cells express high levels of IgM, and low levels of IgD and CD23/Fc epsilon RII. In addition, both mouse and human marginal zone B cells express high levels of CD1 (CD1d in mice, CD1c in humans), and CD21.
What is white and red pulp?
White pulp is material which is part of the immune system (lymphatic tissue) mainly made up of white blood cells. Red pulp is made up of blood-filled cavities (venous sinuses) and splenic cords. Splenic cords are special tissues which contain different types of red and white blood cells.
What is in red pulp?
Red pulp is a loose spongy tissue with chords of reticular cells located between venous sinuses that contains lymphocytes, macrophages, granulocytes, and plasma cells.
Is spleen a tissue?
The spleen is the largest lymphatic organ in the body. Surrounded by a connective tissue capsule, which extends inward to divide the organ into lobules, the spleen consists of two types of tissue called white pulp and red pulp.
Where is germinal center?
B cell follicles
Germinal centers develop in the B cell follicles of secondary lymphoid tissues during T cell-dependent (TD) antibody responses. The B cells that give rise to germinal centers initially have to be activated outside follicles, in the T cell-rich zones in association with interdigitating cells and T cell help.
What is the theory of the marginal zone?
Lewis Binford and Kent Flannery: “Marginal Zone Theory.”. These scholars explain the emergence of agriculture as response to cyclical population pressure on the edges of the Nuclear Zones. This is a systemic theory that focuses on the relationship between population pressure, environment and subsistence strategies.
What kind of cells are in the marginal zone?
Marginal zone B cells (MZ B cells) are noncirculating mature B cells that in humans segregate anatomically into the marginal zone (MZ) of the spleen and certain other types of lymphoid tissue.
What is the central concept of marginalism in economics?
Although the central concept of marginalism is that of marginal utility, marginalists, following the lead of Alfred Marshall, drew upon the idea of marginal physical productivity in explanation of cost.
When does the marginal zone of the spleen form?
The spleen’s marginal zone contains multiple subtypes of macrophages and dendritic cells interlaced with the MZ B cells; it is not fully formed until 2 to 3 weeks after birth in rodents and 1 to 2 years in humans. The MZ B cells within this region typically express high levels of IgM, CD21, CD1,…