From Big Medical Encyclopedia

PLASMOCYTES (the Greek plasma molded, issued; synonym: plasmocytes, Unna's cells) — highly specialized cellular elements of the hemopoietic fabric which function are products of immunoglobulins.

The item to. are allocated in 1891 by P. Unna in a special type of cells thanks to a pronounced basophilia of cytoplasm. Further it was established that this a basophilia is connected with high content in cytoplasm of plasmocytes of RNA that is characteristic of the cells which are actively synthesizing protein. As a result of observations over cultures of lymphocytes and detection among them transitional forms A. A. Maximov assumed that P. to. are formed from lymphocytes (see). In the subsequent it turned out that P. to. are formed only of V-lymphocytes. Interest in P. to. amplified in connection with detection of dependence between increase in an antiserum capacity in the course of hyper immunization and increase in number of P. to. in limf, nodes and a spleen. In 1948 A. Fag-raeus showed that within 2 — 3 days after immunization of animals various antigens in a spleen form «transitional cells» with the big roundish kernel containing many kernels and poorly basphilic cytoplasm. Then there is a reduction of size of these cells and their kernels, and the basophilia and a pyroninophilia (during the coloring by methyl green - pyronin) cytoplasms amplify. Different researchers called «Transitional cells» big lymphocytes, myeloblasts, lymphoblastic P. to., macrohistiocytes, basphilic macrophages.

The item to. in the person and the highest vertebrata in a large number are found in limf, nodes and a spleen. In limf, nodes P. to. hl are located. obr. in pulpy tyazha, and in a spleen — in a red pulp. Often their accumulations surround small blood vessels and are located around lymphatic follicles. In secondary follicles plasmablasts meet generally. The item to. are found also in friable connecting fabric on the course of vessels, in serous covers (especially an epiploon), a stroma of various glands (milk, salivary), a mucous membrane of intestines, marrow.

P.'s most to. are short-lived cellular elements with a life cycle apprx. 2 days, but nek-ry of them exist up to 6 months. At the end of a life cycle of P. to. homogeneous proteinaceous little bodies of Roussel are formed (see. Roussel of a little body ). One P. to. forms, as a rule, antibodies of one specificity. Set P. to. provides synthesis of various antibodies.

Several stages of maturing of P. are known to. At proliferation of the immunocompetent lymphocyte activated by antigen there is a hyperplasia of a granular cytoplasmic reticulum in this connection cells become more pironinofilny. Then they turn into plasmablasts and plasmocytes.

Plasmablast to dia. apprx. 20 mkh has a large kernel with several kernels. Its cytoplasm intensively of a bazofiln (pironinofil-on) also surrounds a kernel with a belt of average width, occasionally in it small vacuoles meet. The kernel is located is central or is excentric, around it the zone of an enlightenment is visible. In cytoplasm the quantity of membranes of a cytoplasmic reticulum and the related ribosomes increases. In unripe P. to. to dia. 20 — 25 microns (Proplazmotsit) chromatinic threads of a kernel are a little thickened, their network is condensed, but chromatin is located rather evenly. The kernel contains one small kernel, the perinuclear zone is usually well-marked, cytoplasm wide, homogeneous or with existence of basphilic vacuoles. The quantity of membranes of a cytoplasmic reticulum continues to increase, the number of ribosomes increases, the lamellar complex (Golgi's device) hypertrophies. Mature P. to. to dia. Excentricly compact kernel of a round or oval form of rather small size located more often with gruboglybchaty structure and focal dense radial accumulations of chromatinic threads — a kolesovidny kernel has 10 — 20 microns. In P. to. intranuclear structures (nuclear little bodies) which fibrillar component contains RNA, and dense granular — DNA are described. Emergence of nuclear little bodies is connected with the strengthened proteinaceous synthesis. The volume of cytoplasm P. to. considerably surpasses the volume of a kernel, it contains many small vacuoles (foamy cytoplasm). Sideways from a kernel, or covering it, is the outlined light field — a centrosphere is clear. Mitochondrions are disseminated through a circle of the light field in cytoplasm.

Diffraction pattern of a plasmocyte: 1 — membranes of a cytoplasmic reticulum, 2 — a kernel, 3 — mitochondrions; X 8000.

The number of electronic and dense granules of secretory character increases in a zone of a hypertrophied lamellar complex. Cytoplasm is overflowed with structures in the form of sacks and tubules, on walls of membranes of a cytoplasmic reticulum (fig.) numerous are visible ribosomes (see); the quantity the policy and free ribosomes sharply decreases. Expanded tanks of an ergastoplazma are filled with electron-dense material.

Synthesis of heavy (N) and light (L) chains of molecules of immunoglobulins happens in ribosomes of a granular cytoplasmic reticulum. Here they combine in the whole immunoglobin molecules (H2L2) cosecreted to the environment. Assembly begins with interaction connected with ribosomes N-tse-pey with a pool of free L-chains. Then within several minutes disulfide bridges are formed and monomers combine in pentameasures (in case of synthesis of IgM) with participation of a L-chain. Transport of immunoglobulins from tubules of a granular cytoplasmic reticulum in a lamellar complex with the subsequent secretion is carried out rather slowly and in 1 hour less than a half of the synthesized molecules cosecretes. On P.'s membrane to. are expressed H-2-antige-ny and a differential antigen of plasmocytes (R. S. The last is absent on P. predecessors to. and the quantity it increases in process of maturing from a plasmablast to mature P. to. On part P. to. the receptor for binding of a Fc-fragment of IgG is defined. The number of specific immunoglobin receptors during the maturing from a plasmablast to mature P. to. decreases. Plasmablasts actively synthesize RNA. In mature P. to. synthesis of RNA is absent. Active formation of protein in them assumes synthesis it on matrixes and in the ribosomes prepared in plasmablasts.

Proliferation of cells plazmotsitarny a row is called plazmotsitarny reaction. Plazmotsitarny reaction is important morfol. criterion immunol, the process which is followed by development antibodies (see). Dynamics it usually advances increase and decrease in an antiserum capacity in blood serum a little. At reimmunization plazmotsitarny reaction is more intensive and develops quicker, than at primary. After administration of antigen in an adenoid tissue the hyperplasia of reticular macrophages, Macrophagic reaction and activation of the V-lymphocytes which are characterized by existence of specific immunoglobin receptors begins (see. Immunocompetent cells ). At the same time there is a number of cellular divisions and of one plasmablast during a differentiation is formed by several hundred mature P. to. They are combined by an origin from the same cell, i.e. they form cellular clone (see). During a differentiation of a plasmablast in mature P. to. not only intensity of synthesis of antibodies changes, but also there is a transition from synthesis of IgM to synthesis of IgG. In several days the volume of a clone decreases. P.'s population to. it is supported at the expense of a differentiation new cells-pre-shestvennikov. In the course of a differentiation from a B-lymphocyte to P. to. specificity and an avidnost of the antibodies developed by cells does not change.

P.'s number to. increases at various infectious, infectious and allergic and inflammatory diseases. P.'s accumulations to. find in granulyatsionny fabric, especially at hron, a purulent inflammation, in specific granulyatsionny fabric at syphilis. In the smaller number of P. to. meets in tubercular granulomas.

Number P. to. increases at rheumatic diseases, cancer, cirrhosis, etc. In blood P. to. appear in small amounts at acute infections, a leukosis. Blastomatous growths of P. to. are observed at multiple myeloma (see) and the isolated plasmacytoma. At Valdenstrem's disease there is a transformation of cells of a lymphoid row in P. to., cosecreting macroglobulin. The immunodeficiency which are followed by P.'s absence to are described., the immunoglobulins synthesizing a certain class, e.g. IgA at a disease Krone. At Bruton's agammaglobulinemia patients have no immunoglobulins of all classes, and P. are not in an adenoid tissue to.

For tsitol, P.'s studying to. use the main dyes (on-likhromny methylene blue, toluidine blue, methyl zele-ny-pyronin, azur-eosine, Romanovsky's mix — Gimza). Great value for studying of an origin and a functional role of P. to. had developed by Koons (A.N. Coons) and soavt. an immunohistochemical method (see. Immunofluorescence ), which gave the chance to identify cells, antibody-containing. The method of local hemolysis in gel Erne — Nordina, allowing to investigate morfofunktsionalny properties of living antiteloobrazuyushchy cells, including P. is widely applied to. (morphology of cells, synthesis of DNA, RNA and protein, synthesis and secretion of specific antibodies, avidnost of synthesizable antibodies, etc.). The immunoenzyme method based on marking of antibodies by peroxidase of horse-radish or use of this enzyme as antigen gives the chance to reveal localization of antibodies in P. to. at the electronic and microscopic level. Radioimmunol, and autoradiographic methods allow to investigate biosynthesis and transport of antibodies in P. to.

See also Cell .

Bibliography: Burnett F. M. Cellular immunology, the lane with English, M., 1971; At r-in and the p A. E., etc. Immunogenesis and cellular differentiation, M., 1978; Petrov R. V. Immunology and immunogenetics, page 45, M., 1976; F r and d e of N - sh t of e y A. Ya. N and the P e r t to about in I. L. Cellular bases of immunity, M., 1969; Avramea s S. a. L e d u with E.N. of Detection of simultaneous antibody synthesis in plasma cells and specialized lymphocytes in rabbit lymph nodes, J. exp. Med., v. 131, p. 1137, 1970; Bessis M. C. Ultrastructure of lymphoid and plasma cells in relation to globulin and antibody formation, Lab. Invest., v. 10, p. 1040, 1961; S e 1 1 S. Immunology, immunopathology and immunity, Hagerstown, 1980; TakahashiT., Old L. J. a. B o y s e E.A. Surfase al-loantigens of plasma cells, J. exp. Med., y. 131, p. 1325, 1970; Tartakoff A. a. V a s s a 1 1 i P. Plasma cell immunoglobulin M molecules, J. Cell Biol., v. 83, No. 2, pt 1, p. 284, 1979, bibliogr.

B. B. Fuchs, L. B. Wanko.