Migration and Lodging of Peyer’s Patch IgA Precursor Cells in the Gut Lamina Propria
A striking feature of the intestine is the presence of a huge number of IgA plasma cells in the lamina propria. The source of these IgA plasma cells is the Peyer’s patches (PP), in which the precursor cells are committed by the antigens from the lumen (1,2). The committed precursor cells then migrate to mesenteric lymph nodes (MLN), enter the blood circulation via the thoracic duct, and eventually arrive in the gut lamina propria (GLP) where they differentiate into resident plasma cells. During the migration, the precursor cells differentiate and expand (2). Two types of IgA precursor cells are present in Peyer’s patches: the IgA bearing cells in the germinal center and the IgM-IgD double bearing cells outside the germinal center (3). The former are sessile cells reactive with peanut agglutinin (PNA) but not MEL-14 monoclonal antibody while the latter are migratory or recirculating cells bearing MEL-14 but not PNA reactive determinants; they are designated as MEL-14(−) PNA(+) and MEL-14 (+) PNA(−) cells, respectively (4). The IgA precursor cells differentiating into IgA containing blasts in the MLN and thoracic duct migrate directly to and lodge permanently in the GLP (5, 6). The small IgA precursor cells migrating indirectly to the GLP expand and differentiate enroute (2). How the differentiation accompanying with migratory-sessile changes occurs in the journey is still unknown. The present study was undertaken to investigate the possible relationship between the reactivities of MEL-14 and PNA and the differentiation-migration of IgA precursor cells. Passive transfers using 1g allotype congeneic mice were conducted; MEL-14 and PNA reactivity were examined for the lymphoid cells. The results suggest that when IgA precursor cells differentiate into blasts and plasma cells they lose MEL-14 and PNA reactivity. Lodging of IgA cells in the gut may require factor other than MEL-14 and PNA reactive determinants.
KeywordsPrecursor Cell Germinal Center Mesenteric Lymph Node Thoracic Duct Passive Transfer
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