B lymphocytes are principal cells that mediate humoral adaptive immunity. After their maturation in the bone marrow, B cells enter peripheral lymphoid tissues, which are the sites of interaction with foreign antigens. Production of antibodies is initiated by the interaction of antigens with a small number of mature B cells specific for each antigen. An antigen binds to the membrane receptors on specific B cells and initiates a series of responses that lead to two principal changes: cell proliferation resulting in expansion of the clone, and differentiation to either plasma cells actively secreting antibodies or to memory cells.
Key words: B cells, subsets of B cells, memory B cells, plasma cells
Antibodies are molecules of glycoprotein nature that have ability to bind antigens either soluble or bound in membranes of cells in a specific way. They are present in plasma and in tissue fluids (lymph, saliva, tears etc.). As most of antibodies belong to the gamma globulins of plasma proteins, they were previously known under the term gammaglobulins; their contemporary nomenclature is immunoglobulins (Ig). There are five classes of immunoglobulins: IgG, IgM, IgA, IgE, and IgE, respectively. They have specific biochemical structure and function. The principal biological role is to bind antigens; except it, they can activate the complement, opsonise bacteria, bind to receptors of various cell of the immune system etc.
Antigen presentation; T cell mediated immunity
.. being previously processed by antigen presenting cells (APCs). Following their processing that.. .. cells are not unique population of cells. There are.. ..keywords: presenting cells, HLA molecules, T cells and their..
.. engulfment and their killing. The phagocytic cells of mammals belong to two complementary systems,.. .. output (leucocytosis ), an increased level of plasma proteins (acute phase proteins: CRP, MBL, ....),.. .. into several steps: recruitment of inflammatory cells into a site where germs entered the body, local..
Foeto-maternal relationships. The immune system of newborns
.. secures it by various mechanisms – special cells, cytokines, HLA molecules, peripheral tolerance.. .. of a blastocyt, invasion of trophoblast cells into decidua and myometrium to enable them an.. ..keywords: NK cells, HLA molecules, tolerance, immune system of..
The complent system and its biological significance
.. accumulate. The complement proteins in the plasma represent 10% of its globulin fraction. The.. .. lectin, and alternative. Except target cells lysis, the complement mediates also other.. ..keywords: complement, lysis of target cells, imune complexes, deficiencies of ..
ENDOCRINE SYSTEM - part II
.. thymus, gonadal glands and also chromaffine cells.. ..keywords: epiphysis, thymus, gonadal glands, chromaffine cells..
Cytokines. PAMPs and PRRs
.. activation, proliferation and differentiation of cells of the immune system. Moreover, cytokines.. .. without them. Moreover, they are not present in cells of their hosts. The term “Pathogen..
Milestones of Immunology, Immune system - an overview, Antigen
.. defence of an organism against germs, cancer cells, toxins etc. Nowadays, Immunology is defined a.. .. numerous leucocytes, macrophages, dendritic cells etc., altogether are there app. 1012 cells. One..
.. Leukocytes and their immune unctions. Plasma - composition, function, osmotic and oncotic..
HLA complex and its significancein biology and medicine
.. proteins present in membranes of all nucleated cells. They form a unique system for which the term.. .. they mediate presentation of antigens to T cells, are involved in cooperation of cells o the..
Blood Physiology (Lecture for the Dentistry Students)
.. and haemostasis. Haemocoagulation. Blood plasma - composition, functios...