[The role of gamma-delta T-lymphocyte subtypes in normal and pathologic conditions]

Abstract

In the review data about origin, spreading in the organism, differentiation, physiologic sense, role in diversity of pathologic processes, and also pharmaco- and immunocorrection's probable foundations of T-lymphocyte's new population with T cell receptor (TcR) gamma delta (TL gamma delta) are resumed. In the phylogenesis TL gamma delta are supposed to be older than T lymphocytes with TcR alpha beta. The conclusion is based upon domination of this lymphocyte population at gestation's early stage and huge representation of pseudogenes in the DNA region that encodes TcR structure of TL gamma delta. A morphological and functional resemblance of the given population with natural killer cells is underlined. It is paid attention to wide representation of TL gamma delta in the periphery tissues, poverty of TcR diapason that may evidence about postdifferentiation's process of TL gamma delta to be accomplished due to TcR genes rearrangement. This process appears to supply the enhancement of antigen-specific TL gamma delta in foreign agent's inculcation. A maturation process and probable mechanisms of these lymphocytes education in thymus is described. A classification of TL gamma delta depending on TcR structure and cytokine profile of the lymphocytes that subdivides them on T-helper/cytotoxic (Vg9/Vd2 phenotype) and cytotoxic/suppressor (Vd1 or Vd3 phenotype) was proposed. In the review the role of TL gamma delta in mucous immunity supporting and possible participating in systemic regulation of the immune response is emphasized. A physiologic role of TL gamma delta, namely ability to identify non-protein antigens (lipopolysaccharides, polyphosphates, glycolipids) and heat shock proteins, is also described. Evidences about uncertainty of incomplete phagocytosis phenomenon in vivo in case of TL gamma delta's normal function are given. Particularly it is made out that these lymphocytes are able to activate inducible NO-synthase in the macrophages that enhances their phagocytic activity in tens time. A function of these lymphocytes in defense against infection of bacterial, viral, protozoa, fungal origin, and also in tumor growth and autoimmune diseases is represented. Methods of specific therapeutic influence upon TL gamma delta, both pharmacological (pamidronat, 2,3-diphosphoglyceric acid) and immunologic profile (monoclonal antibodies conjugated with cytotoxic agent) are given.