Adaptive immune system cells components

The two components of the adaptive immune system (humoral and cell-mediated) are not competitive with each other rather, they work together in harmony. This harmonious attack is facilitated by the cooperative efforts of both B-type and T-type lymphocytes... 

The components of the immunosurveillance are the innate immune system, consisting of monocytes, macrophages, dendritic cells (DC), natural killer (NK) and NKT cells, and the adaptive immune system, represented by DC, B-cells, and T cells (Fig. 1). 

The response to viral infection involves cellular and cytokine components of the host innate and adaptive immune system. However, viruses have developed protean means of subverting the host immune response. This has been an explosive area of research that has revealed striking examples of the diverse strategies CMV has evolved to counteract host immunity. The MHC is the ultimate interface between virus and adaptive immunity. CDS" and CD4 T lymphocytes recognize peptides derived from viral proteins presented in the context of MHC class I and class II molecules, respectively (Doherty 1995). This recognition triggers the cell-mediated immune system armamentarium whereby virus-specific T lymphocyte clones proliferate and mediate cytolysis of virally infected cells and/or release cytokines that inhibit viral replication or recruit T cells and monocytes to amplify the antiviral response. 

Abstract This chapter describes what is known about the main components and responses of the innate and adaptive immune system of fish. The chapter first reviews the organs, cells and molecules of the immune system known in a few economically important or model fish species. Molecular evidence suggests a similar immune system exists throughout the jawed vertebrates yet marked differences are also apparent. The innate parameters are at the forefront of fish immune defence and are a crucial factor in disease resistance. The adaptive response of fish is commonly delayed but is essential for long lasting immunity and a key factor in successful vaccination. 

A. Overview The innate immune system initiates the defense against pathogens and antigenic insult. It involves the concerted actions of complement components, lysozyme, macrophages, and neutrophils. If the innate response is inadequate, the adaptive immune response is mobilized. This culminates in the activation of T lymphocytes, the effectors of cell-mediated immunity and the production of antibodies, by activated B lymphocytes, the effectors of humoral immunity. The cell types involved in immune responses can be identified by specific cell surface components or clusters of differentiation (CDs). For example, T helper cells bear the CD4 protein complex, whereas cytotoxic T lymphocytes express the CDS protein complex. Clusters of differentiation also can be used to characterize other types of hematopoietic cells, including precursors of granulocytes, megakaryocytes, and erythrocytes (Chapter 33). 

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