[The role of hepatic sinusoidal cells in homing of lymphocytes. Preferential hepatic trapping of PNA(+) lymphocyte and its modulation during liver regeneration].

It was demonstrated that the reaction of some cell species to peanut agglutinin (PNA) involved the maturity of the cells. We investigated the selective adhesion of circulating hemopoietic cells and lymphoid cells to hepatic sinusoidal cells. We experimented with thymocyte (TYC) models that could be easily isolated into PNA positive [PNA(+)] and PNA negative [PNA(-)] subsets, and transfused these subsets, labeled with 51Cr into the isogenic mice, then measured the radioactivity in the kidney, lung, spleen, liver, Peyer's patch (P.P.), and thymus, after 48 hrs. The radioactivity (% total dose recovered) in the liver and spleen represented the degree of cellular distribution and indicated that a significantly higher dose had accumulated in the liver and spleen than in other organs. Additionally, TYC-PNA(+), recognized to be immature cells, demonstrated high aggregation in the liver, while TYC-PNA(-), recognized to be mature cells, demonstrated high aggregation in the spleen. Similar results were observed in our subsequent experiment using wheat germ agglutinin (WGA), other indicator of maturity, and spleen cells (SPC). Next, we transfused TYC-PNA(+) to mice at various intervals after 70% hepatectomy. The degree of aggregation (radioactivity/weight) in the liver was reduced 1 day after hepatectomy, and that in the spleen increased proportionately. Whereas the aggregation degree of TYC-PNA(-) in the same experiment did not change significantly. We postulated that hepatic sinusoidal cells recognize and, sequentially, trap specific carbohydrates on lymphoid cells by a lectin, PNA or WGA, like receptor. Reviewing our previous report, adhesion to Kupffer cells induced SPC activation and proliferation, this recognition and trapping mechanism seems to play an important role of intrahepatic hematolymphoid system.