Basic concepts and statements of fundamental immunology

The aim of review. Mammals have complex mechanisms of protection against exogenous pathogenes and internal threats (malignant proliferation). Strategy of protection is based on the presence of two stages of defense: nonspecific (innate immunodefense) and specific (adaptable immunodefense). In the review the basic concepts of innate and adaptable immune responses and their interaction are presented.

State-of-the art. «Operational» components of nonspecific (innate) immune system include macrophages, monocytes, dendritic cells, natural killer cells and neutrophiles which distinguish uniform (conservative) moleculas of pathogenes and moleculas expressed by cells of the host in case of infection or neoplastic transformation. Cells of immune system after exposure to “threat molecules” produce chemokines which recruite inflammatory cells to the focus of damage, and danger is liquidated by joint actions of phagocytic cells, cytotoxic cells, cytokines, proteins of acute phase and complement. Т- and B- lymphocytes acts as instruments of adaptable immune system. T-crates express clonotypical antigenic receptors which distinguish peptide fragments of protein antigens, presenting by molecules of the main histocompatibility complex (MHC) presenting cells (dendritic cells, macrophages). Activation of naive T- cells comes upon after reception of signal from their antigenic receptors (signal 1), and signal of danger from costimultory receptors (signal 2). Activation represents differentiation in effector cells, further capable to carry out the functions in response only to signal 1. Adaptable immune responses to signals of danger (infectious or neoplastic) get either inflammatory nature with involvement of cytotoxic T- cells, Th1-cells and natural killer cells, or antibody-producing nature with participation of Th2-and B-cells. Antibodies neutralize toxins and viruses, opsonize pathogenes for phagocytosis and activate complement. Differentiation of cells in towards Th1/Th2, effectory functions of adaptable immune system and termination of adaptable immune responses are controlled by cytokines produced by T-cells and cells of innate immune system.

Conclusion. Nonspecific (innate) and specific (adaptable) immune systems interreact with each other and adjust each other. Dendritic cells and macrophages play the central role in immune responses of both systems. Т-and B-cells participate mostly in adaptable immune responses though types of T-cells have of nonspecific response functions.

1. Aderem A., Ulevitch R.J. Toll-like receptors in the induction of the innate immune response // Nature. – 2000. – Vol. 406. – P. 782–787.

2. Lenner L.L. NK cell receptors // Ann. Rev. Immunol. – 1998. – Vol. 16. – P. 359–393.

3. Moretta A., Bottino C., Vitale M. et al. Activating receptors and coreceptors involved in human natural killer cell-mediated cytolysis // Ann. Rev. Immunol. – 2001. – Vol. 19. – P. 197–224.

4. O’Farrelly C., Doherty D.G. Basic immunological terms and concepts: a short primer of fundamental immunology // Liver immunology / Eds. Gershwin M.E., Vierling J.M., Manns M.P. – Hanlly & Belfus, Inc., 2003. – P. 1–13.

5. Palucka K., Banchereau J. Linking innate and adaptive immunity // Nature Med. – 1999. – Vol. 5. – P. 868–870.