title: Prolactin increases CD4/CD8 cell ratio in thymus-grafted congenitally athymic nude mice.
abstract: One distinctive effect on T-cell development was analyzed by selectively increasing serum prolactin (PRL) concentration in thymus-grafted congenitally athymic nude mice and by neutralizing PRL in suspension cultures of thymus from 1-day-old neonatal mice. Flow cytometric analysis of single-positive CD4+ and CD8+ cells derived from inguinal lymph nodes revealed a CD4/CD8 cell ratio of 2.2 +/- 0.18 (mean +/- SEM) in thymus-grafted nude mice that is similar to the ratio for immune-competent BALB/c mice (2.0 +/- 0.06). Addition of the pituitary to thymus-grafted nude mice significantly elevated serum PRL (P < 0.005) and increased the CD4/CD8 cell ratio (2.8 +/- 0.12; P < 0.005), demonstrating preferential stimulation of CD4+ cell development. T cells in nude mice receiving sham (submandibular salivary gland) or pituitary grafts alone were below detectable levels. Suspension cultures of neonatal thymus treated with anti-mouse PRL antiserum resulted in 20% and 30% decreases in double-positive CD4+8+ thymocytes and thymocyte viability, respectively. A 10-fold increase in double-negative CD4-8- thymocytes expressing the interleukin 2 receptor alpha chain, CD25, was also observed concurrently. Our findings illustrate an important way in which PRL may participate in two interrelated mechanisms: the regulation of peripheral single-positive cells and the maintenance of thymocyte viability during the double-positive stage of intrathymic differentiation.
authors.affiliation: Group in Endocrinology, University of California, Berkeley 94720-3140, USA.
authors.forename: G O
authors.initials: GO
authors.lastname: Gaufo
authors.forename: M C
authors.initials: MC
authors.lastname: Diamond
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D005434:Flow Cytometry; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D010902:Pituitary Gland / Q000502:physiology* / Q000637:transplantation*; D011388:Prolactin / Q000097:blood / Q000187:drug effects / Q000502:physiology*; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology; D013950:Thymus Gland / Q000502:physiology* / Q000637:transplantation*; D014185:Transplantation, Isogeneic
chemical_list: D011388:Prolactin