Regulatory Lymphocytes in T Cell Functions in Chickens

Abstract

Our contemporary understanding of the immune system involves the concept of two distinct expressions of immunity as well as the division of lymphocyte types into functional subpopulations. Inherent in the development of this complexity is the discernment that some form of control mechanism must have evolved simultaneously. The study of regulatory mechanisms responsible for directing the response (normally) for the benefit of the organism has recently occupied a large number of immunologists. Their results have been frequently reviewed (1–8), and it is unnecessary to add to this literature burden. Rather, this paper will focus on the evidence which is accumulating that chicken thymocytes are capable of regulating the responsiveness of cells present in peripheral lymphoid tissue. Although these cells can regulate both T and B cell functions, emphasis will be placed on the role of these cells in the control of two phenomena which have been classically described as involving T cells.