ROLE OF HARDERIAN-GLAND ON DIFFERENTIATION AND PROLIFERATION OF IMMUNOGLOBULIN-A-BEARING LYMPHOCYTES IN CHICKENS

The mechanism of accumulation of surface immunoglobulin A (sIgA) beari ng cells in chicken Harderian gland (HG) was examined. Almost no sIgA- bearing cells were identified in HG of 1.5-week-old chickens. In 3.5-w eek-old chickens, however, 46.4% of the HG lymphocytes were sIgA-beari ng cells. When bursa of Fabricius (BF) lymphocytes were transferred in to recipients, BF lymphocytes migrated into the HG but the number of t hese lymphocytes was extremely small. In addition, no correlation was found between the surface immunoglobulin class of BF lymphocytes that migrated into HG and the migration. HG lymphocytes were co-cultured wi th HG whole cells (which contained 50-60% configurationally epithelial cells) in a non-contacting manner for 80 h using an Intercell culture vessel. The results showed a significant increase in the ratio of sIg A-bearing cells in HG lymphocytes compared with the control which was cultured without placing HG whole cells in the external well. B lympho cytes that migrated into HG seemed to undergo specific differentiation in situ into sIgA-bearing cells owing to microenvironmental factors, probably humoral factors excreted from HG epithelial cells, and subseq uently undergo proliferation to result in accumulation of sIgA-bearing cells in HG tissue.