Author/Editor		Zavašnik-Bergant, Valentina; Schweiger, Ana; Bevec, Tadeja; Golouh, Rastko; Turk, Vito; Kos, Janko
Title		Inhibitory p41 isoform of invariant chain and its potential target enzymes cathepsins L and H in distinct populations of macrophages in human lymph nodes
Type		članek
Source		Immunology
Vol. and No.		, št. 112
Publication year		2004
Volume		str. 378-85
Language		eng
Abstract		Activation of the CD4+ T-cell mediated immune response relies on the proteolytic capacity of enzymes involved in modulating major histocompatibility complex (MHC) II-associated antigen presentation in antigen-presenting cells (APC). The MHC II-associated chaperone molecule p41 isoform of invariant chain (inhibitory p41 Ii) has been suggested to regulate stability and activity of cathepsin L in these APC. In the present study the human lymph node distribution of noninhibitory p31 Ii and inhibitory p41 Ii have been compared by differential labelling, using two specific monoclonal antibodies. The distribution of p41 Ii, but not p31 Ii, matched the distribution of cathepsins L and H in subcapsular and cortical sinuses and germinal centres. Co-localization of p41 Ii with cathepsin H was confirmed in strongly CD68+ sinus-lining macrophages, acting as APC. Furthermore, p41 li was determined together with cathepsins L and H in tingible body macrophages, highly phagocytic, but not antigen-presenting cells inside germinal centres. With respect to the physiological function that these two populations of macrophages have in human lymph nodes, our results support a regulatory function of p41 Ii towards cathepsins L and H in human macrophages, associated with the processes of phagocytosis rather than antigen presentation.
Descriptors		ANTIGENS, DIFFERENTIATION, B-LYMPHOCYTE CATHEPSINS CYSTEINE PROTEINASES LYMPH NODES MACROPHAGES ANTIBODIES, MONOCLONAL ENZYME-LINKED IMMUNOSORBENT ASSAY HISTOCOMPATIBILITY ANTIGENS CLASS II IMMUNOHISTOCHEMISTRY MICE, INBRED BALB C PHAGOCYTOSIS RECOMBINANT PROTEINS