Ligand-independent signaling during early avian B cell development.
Surface immunoglobulin (sIg) expression has been conserved as a critical checkpoint in B lymphocyte development. In the chicken embryo, only sIg+ B cells are selectively expanded in the bursa of Fabricius, a primary lymphoid organ unique to the avian species. We have previously demonstrated that an interaction between the antigen- binding sites of sIg and a specific bursal ligand(s) is not required to regulate this developmental checkpoint. Rather, the requirement for sIg expression can be attributed to the surface expression of the Igalpha/beta heterodimer associated with sIg. More specifically, ligand-independent signaling downstream of the Igalpha cytoplasmic domain drives all bursal stages of B cell development during embryogenesis. We discuss here a site-directed mutagenesis approach to identify the critical membrane proximal events involved in ligand-independent signaling during B cell development.
Pike
Kelly A
KA
Department of Immunology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada.
Ratcliffe
Michael J H
MJ
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D002454:Cell Differentiation; D002642:Chick Embryo; D002645:Chickens / Q000276:immunology*; D007136:Immunoglobulins / Q000235:genetics / Q000378:metabolism*; D008024:Ligands; D011947:Receptors, Antigen, B-Cell / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*
D007136:Immunoglobulins; D008024:Ligands; D011947:Receptors, Antigen, B-Cell