80. Stimulation of the humoral link of immunity: participants in immunity, causes. Pathological anatomy of changes in the organs of the immune system (in the lymph nodes, spleen, bone marrow, thymus).

The humoral immune response is the activation of B lymphocytes and the elimination of microbes located extracellularly.As a result of activation, B lymphocytes proliferate and differentiate into plasma cells that secrete antibodies of various classes.In humans, five classes of antibodies (immunoglobulins) are formed: IgD, IgM, IgG, IgA, IgE. There are 3 links in the reactions of humoral immunity:

1. Afferent.

2. Central.

3. Efferent.

1) Aferent is the path from the site of antigen insertion to the thymus. At the same time, the following happens:

1. capture of antigen by macrophages;

2. antigen processing in the cytoplasm of a macrophage with the formation of dominants;

3. the passage of dominants from macrophages to T-lymphocytes

4. information about the T-lymphocyte antigen of the central organs of immunity (thymus, lymphoid tissue).

2) The central one is the pathway from the thymus to the lymphoid tissue. Along this path, information is recorded in the thymus and this information is communicated to B lymphocytes.

3) Efferent is a peripheral lymphoid tissue.

In this link, there are:

Proliferation of B lymphocytes.

Plasmatization of lymphoid tissue

Formation of specific antibodies.

The antigen+antibody reaction.

Capture of the antigen +antibody complex and its destruction by the macrophage. At the same time, the macrophage reaction increases 100 times. . CHANGES IN THE THYMUS IN IMMUNOGENESIS DISORDERS The thymus plays a central role in immunity and pathology of immunity.

The thymus (thymus gland) is built of lymphoid tissue and epithelial cells. In childhood, it is a well-developed organ. Subsequently, as the body matures, its involution occurs. Lymphoid tissue is replaced by fatty tissue. But the remnants of lymphoid tissue and epithelial cells persist for life.

There are 3 types of thymus disorders associated with immunopathological conditions:

Accidental involution. This is the progressive destruction of thymocytes, thymus atrophy in childhood. Causes: long-term debilitating diseases. The result: immune defenselessness and the development of severe infectious diseases caused by viral and bacterial micro-organisms with fatal outcome.

Hyperplasia. Hyperplasia of the thymus and lymphoid tissue (Status thymico-limphaticus). At the same time, there is atrophy of the adrenal cortex, gonads, obesity, high sensitivity to infections, high sensitivity to anesthesia and medications. Death occurs with the phenomena of a hypotonic crisis provoked by the above factors.

Hypolasia. (hereditary pathology).

Variants:

Lymphocytophthysis (Glanzman-Rinicker disease). A total defect of cellular and humoral immunity. The outcome is a rapid death from infection.

Ataxia is telangiectasia (Louis-Bar disease). Hypoplasia of thymus and lymphoid tissue, cerebellar cortex atrophy, conjunctival telangiectasia. Immune defenselessness.

Lymphopenia with normal plasmocytes (Nezelope syndrome). The tendency to infections due to a defect in cellular immunity.

Aplasia of the thymus and parathyroid gland (Di George syndrome). Immunodeficiency. Convulsive syndrome (tetany). CHANGES IN LYMPHOID TISSUE DURING ANTIGENIC STIMULATION

Under the influence of the antigen, the following processes occur in lymphoid tissue associated with the connection of humoral and cellular immunity. Humoral immunity. Lymph nodes. An increase in size. Swelling. Sealing. Hyperplasia of B lymphocytes in dependent areas, where a lot of plasmocytes, plasmoblasts appear with a simultaneous decrease in lymphocytes and an increase in the number of macrophages. Sinus cells proliferate and are partially rejected.

The spleen. Fullness of blood. Edematous swelling of the stroma due to increased permeability of microvessels. Follicle enlargement. Lymphocyte hyperplasia in the pulp and especially in the dependent areas.

An increase in the number of plasmocytes and macrophages. Proliferation and desquamation of the endothelium of the cisnuses.