Mice deficient in invariant-chain and MHC class II exhibit a normal mature B2 cell compartment.
The role of the invariant chain (Ii), an MHC class II-associated chaperone, in B cell development is controversial. Ii deficient mice (Ii(-/-) mice) show a defect in B cell development. This defect has been attributed to the absence of a fragment liberated from the Ii by intramembranous proteolysis. It was proposed that this fragment is required for activation of the NF-kappaB pathway as a means of controlling B cell maturation. The opposing view holds that defects in the assembly of MHC class II molecules result in impaired B cell development. Here we demonstrate that a lack of Ii indeed causes defects in B cell development, with fewer mature B cells in the periphery as previously reported, but that in a compound-mutant from which both Ii and all MHC class II subunits are absent, B cell development is normal. We suggest that neither Ii itself, nor the MHC class II products are required for normal B cell development.
Maehr
René
R
Department of Pathology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA.
Kraus
Manfred
M
Ploegh
Hidde L
HL
D000818:Animals; D000944:Antigens, Differentiation, B-Lymphocyte / Q000235:genetics* / Q000276:immunology; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D015415:Biomarkers; D001853:Bone Marrow / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000235:genetics* / Q000276:immunology; D051379:Mice; D018345:Mice, Knockout; D013154:Spleen / Q000276:immunology
D000944:Antigens, Differentiation, B-Lymphocyte; D015415:Biomarkers; D000949:Histocompatibility Antigens Class II; C045084:invariant chain