Phenotype of HML-1-Positive and HML-1-Negative T Lymphocytes in the Human Intestinal Lamina Propria

Abstract

Intestinal lymphocytes encounter antigen in the afferent limb of the gut-associated lymphoid tissue (i.e. the Peyer’s Patches of the small intestine and the lymphoid follicles of the colon and rectum) and then recirculate to the efferent limb, comprising lymphocytes in the epithelium above the basement membrane (intraepithelial lymphocytes) and lymphocytes diffusely spread in the lamina propria (lamina propria lymphocytes, LPL). LPL thus are antigen-activated lymphocytes. In this regard they resemble the so-called memory cells, which differentiate from naive (or virgin) precursor cells upon antigenic stimulation. We therefore postulated that LPL might represent a tissue-specific subpopulation of memory cells.