DETECTION OF CELL-ADHESION MOLECULES ON HUMAN LIVER-ASSOCIATED LYMPHOCYTES

Liver-associated lymphocytes (LAL) from human liver are phenotypically and functionally different from peripheral blood lymphocytes (PBL). P henotypically, they are mainly represented by the CD3(+/-) CD56(+) phe notype and functionally they spontaneously possess lymphokine-activate d killer (LAK) activity. In this study we evaluated the expression of cell-adhesion molecules (CAM) which could be involved in LAL contacts with other sinusoidal cells and/or be responsible for the LAK activity . The LAL population was isolated by sinusoidal high-pressure lavage f rom partial hepatectomies obtained from patients operated on: for beni gn liver disease (n=6). Surface expression of the pa integrin chains ( CD18, CD11a, CD11b, CD11c), as well as that of members of the immunogl obulin superfamily (CD2, CD54, CD56, CD58), were analysed by one or tw o-colour flow cytometry. Quantitative and qualitative differences were observed in the expression of CAM between LAL and PBL. LAL were chara cterized by an increase in the percentages of CD11b(+), CD54(+), CD56( +) and CD58(+) cells and a decrease in the percentage of CD2(+) cells compared to PBL. Fluorescence intensity values for CD2 and CD56 were h igher in LAL than in PBL. Moreover, CD11a/CD18 cells presented a bimod al distribution (dim and bright) in both PBL and LAL; whereas these tw o subpopulations were equally represented in PBL, the number of bright cells was significantly greater (> 80%) in LAL. The increase in CAM e xpression (percentage of positive cells and intensity of fluorescence) on LAL combined with their increase in natural killer (NK) and LAK ac tivities already reported, support the idea that, at least some, LAL m ight be, compared to PBL, in an activated state in vivo.