Microbiology Notes | Biochemistry,Immunolgy,Cell biology

Complement Pathways: Types, Functions and Regulation Complement was discovered by Jules Bordet as a heat-labile component of normal plasma that causes the opsonisation and killing of bacteria. It helps antibodies and phagocytic cells to clear pathogens and damaged cells; promote inflammation and attack pathogen’s plasma membrane. Proteins that take part in the complement system are called complements that collectively work as a biological cascade The complement system refers to a series of >20 proteins, circulating in the blood and tissue fluids. Most of the proteins are normally inactive, but in response to the recognition of molecular components of microorganisms they become sequentially activated in an enzyme cascade – the activation of one protein enzymatically cleaves and activates the next protein in the cascade. Complements are mainly denoted by the capital letter C with numbers; like, C1, C2, C3, and so on. Some have only alphabet, like, B , D . Some are simpl...

Lymphocytes Lymphocytes are white blood cells that are also one of the body's main types of immune cells. They are made in the bone marrow and found in the blood and lymph tissue. It constitute 10-20% immuno cells of body and 99% of the lymph. Types of lymphocytes  There are present three type of lymphocyte cell this are; B - Cell T - Cell  Natural killer Cell. 1. B-Cell  The B lymphocyte derived its letter designation from its site of maturation, in the bursa of Fabricius in birds; the name turned out to be apt, for bone marrow is its major site of maturation in a number of mammalian species, including humans and mice Mature B cells are defi nitively distinguished from other lymphocytes and all other cells by their synthesis and display of the B-cell receptor (BCR), a membrane-bound immunoglobulin (antibody) molecule that binds to antigen.  The number of B-Cell receptor on surface is approximately 1.5–3 105. B lymphocytes also can improve...

SPLEEN The spleen is the maior site of immune responses to blood,-borne antigens.  It is a large, ovoid secondary lymphoid organ situated high in the left abdominal cavity. While lymph nodes are specialized for trapping antigen from local tissues, the spleen specializes in filtering blood and trapping blood-borne antigens; thus, it can respond to systemic infections. Unlike the lymph nodes, the spleen is not supplied by lymphatic vessels. Instead, blood borne antigens and lymphocytes are carried into the spleen through the splenic artery.  spleen-microbiologywiki   Structure     The spleen is surrounded by a capsule that extends a number of projections (trabeculae) into the interior to form a compartmentalized structure. The compartments are of two types,                       The red pulp         ...