Immunology – the science that studies the immune system and the use of immunological techniques and concepts in other areas of science and practice.
Immunity (Jmmunitas – freedom from something) is called the set of properties and mechanisms that ensure the constancy of the composition of the organism and its protection against infections and other foreign agents for him. Specifically it boils down to control development and action in the body of microorganisms and immunological surveillance of homeostasis (constancy of composition) own cells and tissues, including the processes of morphogenesis, regeneration, as well as timely removal of obsolete, damaged, mutant, and tumor cells.
The immunological functions are carried out on two levels.
The first phylogenetically more ancient level, are non-protective mechanisms against any alien factor. These mechanisms operate constantly and provide a condition, called “innate, natural immunity or nonspecific resistance”.
Non-specific resistance mechanisms operating in the body forever, causing in cases of massive microbial or other destabilizing effects of the inflammatory response, it is the same for different pathogens. The development of the inflammatory reaction contributes to the emergence of specific immune response, which can be seen as a development of the second, more effective line of defense against the pathogen infection process.
The second level of immunological functions constitute the mechanisms that define the body’s ability to selective (specific) response to specific foreign structures, called antigens. This ability is formed in the body in response to exposure to a specific antigenic substance. This group of functions has been called acquired, or specific, immunity.
Natural immunity leads to a constant level of resistance of the organism to any alien substrate, but due to the same type of non-response to different potentially hazardous agents is less efficient than acquired immunity. The development of specialized responses provides local high impact on the object, whose intensity at the peak of the reaction by several orders of magnitude higher than at the beginning of the process. Innate and acquired immunity realized by the action of cells and humoral factors that led to the formulation of terms of cellular and humoral immunity.
A feature of acquired immunity is the development of immunological memory – the ability to a rapid and strong response to re-exposure to antigen. In accordance with this reaction on first exposure to antigen is called “primary response”, and the reaction on re-exposure to antigen – the “secondary response.” After the transfer of infectious diseases formed a condition called post-infectious immunity, which is of high resistance to possible re-development of the same disease. Analogous post-infection immunity is vaccine-induced immunity that develops after vaccination (vaccination). In some diseases (tuberculosis, syphilis) resistance to re-infection persists for such time as in the body there is a pathogen. Such immunity is called infectious or non-sterile. The formation of acquired immunity – the process of active adjustment of the immune system, leading to the formation of humoral or cellular immunity – antibodies and cells that can effectively interact with the antigens that caused the development of immune response. In these cases, the resulting immunity is called active.
Antibodies and immune cells in the body can cause the immune status in a different body, if will be transferred artificially or fall naturally. This immunity called passive. Passive immunity occurs after the introduction of prophylactic or therapeutic sera or selected ones of immunoglobulins. Passive immunity is formed of a newborn child due to the receipt of maternal antibodies through the placenta during pregnancy (placental immunity) or colostrum and milk when feeding the baby. The immunity received from the mother, may be called maternal immunity. To create passive immunity using transplantation of lymphocytes of the immune body or the patient’s own cells activated by antigen or cytokines in vitro. Such immunity has been termed adaptive (perceived). Immunity can be generated against microorganisms, their toxins, viruses, antigens of tumors. In these cases the immune system called antimicrobial, antitoxic, antiviral, antitumor, respectively. When the transplant occurs is incompatible tissue transplantation immunity (graft rejection of the transplant).
Transplanted cells of the immune system (e.g. bone marrow cells) can cause the recipient’s reaction “transplant against host”. Immune response can, under certain conditions, to occur against self-antigens of the body. These responses are called autoimmune. Intake of antigen through the respiratory tract, digestive tract and other areas of the mucous surfaces and skin often leads to the development of a pronounced local immune response. In such cases, we are talking about local immunity. The flow of the antigen in some portions of the mucous surfaces causes the development of secretory immunity that is associated with the formation of secretory immunoglobulin A, which protects all mucous surfaces. However, no organ and no the fabric does not have isolated from the body’s self-immune system and local immunity is considered as a local manifestation of the overall immune system of the body.