Mlk. Tang et al., INTRINSIC DIFFERENCES IN L-SELECTIN EXPRESSION LEVELS AFFECT T-LYMPHOCYTE AND B-LYMPHOCYTE SUBSET-SPECIFIC RECIRCULATION PATHWAYS, The Journal of immunology, 160(10), 1998, pp. 5113-5121
Lymphocyte migration into lymphoid organs is regulated by tissue-speci
fic adhesion molecules such as L-selectin and the alpha(4) beta(7) int
egrin, Whether L-selectin also regulates lymphocyte subset-specific mi
gration into specific lymphoid tissues was examined in this study by c
omparing the migration of CD4(+) T cells, CD8(+) T cells, and B cells
from L-selectin-deficient and wild-type mice. T cells were the predomi
nant lymphocyte subset entering PLN, MLN, Peyer's patches, and spleen
during short term (l-h) migration assays. However, both B cell and CD4
(+) and CD8(+) T cell entries into PLN, MLN, and Peyer's patches were
dramatically impaired (73-98%) by loss of L-selectin, Lymphocyte expre
ssion of alpha(4) beta(7) integrin did not compensate for the loss of
L-selectin, since both B and T cells predominantly migrated into the s
pleen in the absence of L-selectin, The more efficient migration of T
cells into peripheral lymphoid tissues relative to that of B cells was
partly explained by the finding that T cells expressed L-selectin at
50 to 100% higher levels than B cells, In addition, a 50% reduction in
L-selectin expression by lymphocytes from hemizygous L-selectin(+/-)
mice resulted in a 50 to 70% decrease in short term lymphocyte migrati
on into peripheral lymphoid tissues relative to that of wild-type lymp
hocytes. Thus, the differential-migration of T and B lymphocyte subset
s to lymphoid tissues is regulated in part by subset-specific differen
ces in L-selectin expression levels.