title: CD40-deficient mice generated by recombination-activating gene-2-deficient blastocyst complementation.
abstract: To study the role of B-cell antigen CD40 in immune responses, mouse embryonic stem (ES) cells in which both copies of the gene encoding CD40 had been disrupted by homologous recombination were injected in RAG-2 (recombination-activating gene-2)-deficient blastocysts to generate chimeras in which all mature lymphocytes are derived from the CD40-deficient ES cells. T- and B-cell number and phenotype were normal in the CD40-/- chimeras. However, B cells failed to proliferate and undergo isotype switching in vitro in response to soluble CD40 ligand (sCD40L) with interleukin 4 (IL-4) but responded normally to lipopolysaccharide (LPS) with IL-4. CD40-/- chimeras completely failed to mount an antigen-specific antibody response or to develop germinal centers following immunization with the T cell-dependent (TD) antigen keyhole limpet hemocyanin. In contrast, CD40-/- mutant mice responded normally to the T cell-independent (TI) antigens, 2,4,6-trinitrophenyl (TNP)-LPS and TNP-Ficoll. The most noticeable alteration in the serum immunoglobulin levels of young (6-8 weeks old) CD40-/- animals was absence of IgE and severe decrease of IgG1 and IgG2a. These results confirm the essential role of CD40- CD40L interactions in the antibody response to TD antigens and in isotype switching.
authors.affiliation: Division of Immunology, Children's Hospital, Boston, MA.
authors.forename: E
authors.initials: E
authors.lastname: Castigli
authors.forename: F W
authors.initials: FW
authors.lastname: Alt
authors.forename: L
authors.initials: L
authors.lastname: Davidson
authors.forename: A
authors.initials: A
authors.lastname: Bottaro
authors.forename: E
authors.initials: E
authors.lastname: Mizoguchi
authors.forename: A K
authors.initials: AK
authors.lastname: Bhan
authors.forename: R S
authors.initials: RS
authors.lastname: Geha
mesh_terms: D000818:Animals; D000917:Antibody Formation; D015703:Antigens, CD / Q000235:genetics* / Q000502:physiology; D000944:Antigens, Differentiation, B-Lymphocyte / Q000235:genetics* / Q000502:physiology; D001402:B-Lymphocytes / Q000276:immunology; D001755:Blastocyst; D019013:CD40 Antigens; D004268:DNA-Binding Proteins; D005434:Flow Cytometry; D005816:Genetic Complementation Test; D015698:Genomic Library; D007073:Immunoglobulin E / Q000096:biosynthesis / Q000097:blood; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000097:blood; D007075:Immunoglobulin M / Q000096:biosynthesis / Q000097:blood; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology*; D051379:Mice; D010581:Peyer's Patches / Q000276:immunology; D011506:Proteins / Q000235:genetics*; D011995:Recombination, Genetic; D012016:Reference Values; D015183:Restriction Mapping; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; D019013:CD40 Antigens; D004268:DNA-Binding Proteins; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011506:Proteins; C499308:Rag2 protein, mouse; C064655:V(D)J recombination activating protein 2; D007073:Immunoglobulin E