Distribution of alpha(4)beta(7) and alpha(E)beta(7) integrins on thymocytes, intestinal epithelial lymphocytes and peripheral lymphocytes

beta(7) is express on subsets of thymocytes, while T and B lymphocytes show heterogeneous expression of beta(7). Here, we examine the phenotype of the thymocyte and lymphocyte subsets which express alpha(4) beta(7) and alpha(E) beta(7) using mAb against alpha(E), beta(7) and mAb DATK32 which recognizes a combinatorial epitope on alpha(4) beta(7). beta(7)(+) thymocytes have a mature phenotype: TcR(+), CD11a(hi)CD44(hi)HSA(dull). Small subsets of double-negative CD4(-)CD8(-), single-positive CD4(+) and CD8(+) thymocytes express beta(7), while double positive CD4(+) CD8(-) thymocytes are B-7(-). However, two integrins alpha(E) beta(7) and alpha(4) beta(7) recognized by anti-beta(7) are not expressed on an identical subpopulation of thymocytes, as alpha(E) beta(7)(+) alpha(4) beta(7)(-), alpha(E) beta(7)(+) alpha(4) beta(7)(-) and alpha(E) beta(7)(-) alpha(4) beta(7)(+) thymocyte subsets are evident. Similarly, intraepithelial lymphocytes express high levels of alpha(E) beta(7) but little alpha(4) beta(7). In the spleen, Peyer's patches and lymph nodes, alpha(4) beta(7) is expressed at higher levels on most B lymphocytes than on the majority of T lymphocytes, while a small subset of T lymphocytes, which includes both CD4(-) and CD8(+) lymphocytes, express high levels of beta(7) in the form of alpha(4) beta(7) and alpha(E) beta(7), although, as observed with lymphocytes, not all alpha(4) beta(7)(hi) CD4(+) lymphocytes express alpha(4) beta(7). The population of alpha(4) beta(7)(hi) CD4 lymphocytes are enriched in Peyer's patches and form subsets of the memory CD4(-) lymphocyte population, which can be further subdivided on the basis of alpha(E) beta(7), L-selectin and alpha(4) expression. Therefore, memory CD4(+) lymphocytes are highly heterogeneous in their expression of adhesion receptors, and presumably these subpopulations will exhibit very different trafficking properties.