The Origin and Properties of Peripheral Lymph Mononuclear Phagocytes

Abstract

Afferent (peripheral) lymph differs from efferent (central) lymph in that a proportion of its cells resembles mononuclear phagocytes (reviewed in Yoffey & Courtice 1970). Little is known about the origins, properties, and fate of these cells, and even less about their functions; indeed, it is not certain that all of them belong to the mononuclear phagocyte lineage. However, their presence in the major pathways of antigen transport from the periphery to lymph nodes makes it possible that they may be concerned in such transport or in the presentation of antigen to lymphocytes, and thus it is clearly important to study this population of cells in detail. The neglect of lymph-borne mononuclear phagocytes stems largely from the technical difficulties encountered in obtaining them in large numbers, or over a long period of time. Only in the sheep has long-term cannulation of afferent lymphatics been achieved (Smith et al. 1970) atbut the size and the lack of inbred lines of sheep have prevented detailed analytical experiments.