Lymphocytes involved in cell-mediated immune responses and methods to assess cell-mediated immunity

With increasing need for the development of vaccines against many poultry diseases, it is important to understand host immune mechanisms involved in protection against diseases. Because of increasing evidence suggesting a role of cell-mediated immunity in disease resistance against many poultry disease, investigation of immune systems involved in cell-mediated immunity is crucial for the development of immunological control strategies. Recent advances in hybridoma technology and cellular immunology have facilitated the understanding of the ontogeny, structure, and function of the avian immune system. Isolation and flow cytometric analysis of single lymphoid cells now enables researchers to dissect various components of the avian immune system and to investigate the role of subpopulations of lymphocytes in disease processes. In vitro assays are used to asses the host cellular response based upon antigen-specific lymphoproliferation, specific cellular effector function, and lymphokine secretion. These various assays can be used to quantify and qualify host immune responses and to better understand host immunity.