A success of pregnancy depends on a proper implantation and induction of immune tolerance. The immune system secures it by various mechanisms – special cells, cytokines, HLA molecules, peripheral tolerance take part in.
The immune system of the newborn has also its own specifics as it matures relatively long time till it reaches the same protective ability as characteristic for adults.
The lecture deals with primary and secondary immunodefeciencies. It gives an overview on general clinical manifestations and their divisions according to the type of the immune functions defects. Must of the lecture devotes to AIDS.
Type I hypersensitivity belongs to the most common disorder mediated by immune reactions; it affects app. more than 30% of all individuals in Caucasoid population. Type I hypersensitivity is commonly called allergy. It is characterised by rapid onset (hence the term immediate hypersensitivity), within minutes of antigen challenge, and results in conspicuous clinical symptoms.
Cytokines are soluble peptides that induce activation, proliferation and differentiation of cells of the immune system. Moreover, cytokines influence functions of cells of other tissues and organs, esp. of nervous and endocrine systems. They act in very low concentrations (10-10 M) what makes them to be like hormones. However, hormones tend to be produced constitutively and are produced by endocrine organs. Cytokines, on the contrary, are secreted after activation of particular cells and secretion is short-lived, generally ranging from a few hours to a few days and there are no specialised organs for their synthesis. Cytokines influence target cell in 4 different ways, synergistic, antagonistic, pleiotropic, and redundant way, respectively. They ca act in a autocrine, paracrine and endocrine manner. There are many cytokines that can be divided into those regulating innate and adaptive immunity, to the group of cytokines endowed by chemotactic properties and those supporting growth of hematopoietic and immune system cells.
Histocompatibility molecules are genetically determined proteins present in membranes of all nucleated cells. They form a unique system for which the term “Major Histocompatibility Complex (MHC)” was coined. Each vertebrate species is characterised by its own MHC; that of humans has an abbreviation HLA. This acronym is derived from the words: “human leucocyte antigens” as its fist molecules were discovered in membranes of leucocytes.
Antibodies manage to protect us against germs principally by two ways: by enveloping their surfaces (opsonisation), what makes their engulfment and killing by phagocytes easier and more effective or by cell lysis. However, in this case, they need a help from the complement system.
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.
Common people perceive Immunology as a scientific branch that studies defence of an organism against germs, cancer cells, toxins etc. Nowadays, Immunology is defined a scientific branch that studies immunity, its cellular and molecular processes that proceed after a foreign substance, an antigen, enters our body. There are many notable personalities who contributed to its development. Let us mention only some of them – Louis Pasteur, Ilja Mecnikov, Jean Dausset and many, many others. They contributed to the fact that Immunology belongs to those scientific disciplines that develop the most intensively in recent years.
Definition and composition of blood, its function. Determination of hematocrite, erythrocyte sedimentation rate and osmotic resistance.
Blood groups, its determinants, Rh factor, complicationts of transfusion