title: The ontogeny of murine B lymphocytes. I. Induction of phenotypic conversion of Ia-to Ia+ lymphocytes.
abstract: When bone marrow and spleen cells of 4 week-old mice are fractionated on a discontinuous BSA gradient, a small fraction of Ia- cells is obtained which can be induced in vitro to express the Ia alloantigen within 2 hr. This is in precise parallel to the prothymocyte induction system of Komuro and Boyse. Ia specificity is ascertained by the use of two reciprocal antisera, A.TH anti-A.TL (anti-Iak) and A.TL anti-A.TH (anti-Ias), which yield the expected reaction pattern on induced bone marrow cells of (B6 X A)F1 (Iak) and SJL/J (Ias) mice. Induction can be effected by a number of agents, such as catecholamines, prostaglandin PGE1, cAMP, bacterial endotoxin, lipid A, ubiquitin, and thymopoietin. The last requires a 100-fold higher concentration for Ia+ induction as compared to prothymocyte induction, thus implying a lower affinity for the B cell receptor than for the thymocyte receptor. Ia- to Ia+ conversion involves cells different from prothymocytes, as indicated by: 1) the specific cytolytic effect of our anti-Ia sera which were shown to be free of activity against thymocytes; 2) an additive cytolytic effect of anti-Ia and anti-Thy-1 sera; and 3) the fact that the Ia inducible cells are sensitive to pretreatment with anti-immunoglobulin and C. This finding that Ia- precursor cells are already Ig+ is of interest for the B cell ontogeny, as it implies that Ig expression precedes Ia expression.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D001853:Bone Marrow / Q000276:immunology; D001854:Bone Marrow Cells; D003994:Bucladesine / Q000494:pharmacology; D002395:Catecholamines / Q000494:pharmacology; D003165:Complement System Proteins; D000242:Cyclic AMP / Q000494:pharmacology; D003601:Cytotoxicity Tests, Immunologic; D004731:Endotoxins / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D007104:Immune Adherence Reaction; D007106:Immune Sera / Q000302:isolation & purification; D007114:Immunization; D007141:Immunoglobulin Fc Fragments / Q000032:analysis; D007136:Immunoglobulins / Q000302:isolation & purification; D007519:Isoantigens; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008815:Mice, Inbred Strains; D010641:Phenotype; D011458:Prostaglandins E / Q000494:pharmacology; D011817:Rabbits; D013154:Spleen / Q000276:immunology
chemical_list: D002395:Catecholamines; D004731:Endotoxins; D007106:Immune Sera; D007141:Immunoglobulin Fc Fragments; D007136:Immunoglobulins; D007519:Isoantigens; D011458:Prostaglandins E; D003994:Bucladesine; D003165:Complement System Proteins; D000242:Cyclic AMP