Liver-derived high density lymphocytes as a new member of resident cells in mouse liver

Pit cells, which are recovered in low density fraction of lymphocytes derived from the liver (L-Fr.1,2), are recognized as perisinusoidal cells. In the present study, the accumulation of liver-derived low (L-Fr.1,2) and high (L-Fr.3,4) density 51Cr-labeled lymphocytes was assessed in the liver, spleen and peripheral blood of syngeneic BALB/c mice in comparison with those derived from the spleen (S-Fr.1,2 and S-Fr.3,4) and peripheral blood (P-Fr.1,2 and P-Fr.3,4). L-Fr.1,2, L-Fr.3,4 and P-Fr.1,2 accumulated selectively in the liver, whereas P-Fr.3,4 did not accumulate in the liver. L-Fr.3,4 was composed of two major subpopulations; Thy1+CD4+ and Thy1+CD8+. This suggested that L-Fr.3,4 were distinctive from P-Fr.3,4 or L-Fr.1,2 and inhabited the liver. P-Fr.1,2 and S-Fr.1,2 tended to accumulate in the liver and 51Cr labeled P-Fr.1,2 and S-Fr.1,2 were recovered mainly in L-Fr.1,2 L-Fr.3,4, S-Fr.1,2 and P-Fr.3,4 48 h after the transfer of these cells, suggesting that a part of P-Fr.1,2 and S-Fr.1,2 might be in dynamic equilibrium with those of L-Fr.1,2 and could be a part of the source of L-Fr.3,4. Results also suggested that some of L-Fr.1,2 of T cell lineage might change into L-Fr.3,4 in the liver and might be released into the systemic circulation. Thereafter, L-Fr.3,4 might behave as P-Fr.3,4 and no longer show organ-specific accumulation.