title: CD40L-null NKT cells provide B cell help for specific antibody responses.
abstract: CD1d-binding glycolipids exert potent adjuvant effects on T-dependent Ab responses. The mechanisms include cognate interaction between CD1d-expressing B cells and TCR-expressing Type I CD1d-restricted natural killer T cells (NKTs). However, the critical NKT-derived factors that stimulate B cells are poorly understood. We tested the hypothesis that CD1d-driven CD40L expression by NKT cells influences humoral immunity. Bone marrow chimeras with CD40L(+/+) or CD40L(-/-) NKT cells were immunized with Ag plus CD1d ligand before measuring Ab responses. CD40L(-/-) NKT cells stimulated higher endpoint Ab titers than controls expressing CD40L. In contrast, immunization of CD40L(-/-) mice revealed that CD40L(-/-) NKT cells could not provide B cell help when Th cells lacked CD40L. We report that CD40L(-/-) NKT cells can provide help for Ab production and do so cooperatively with CD40L(+/+) Th cells. We suggest that the manner in which NKT cells provide B cell help is distinct from that of Th cells.
authors.affiliation: Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, United States.
authors.forename: Hemangi B
authors.initials: HB
authors.lastname: Shah
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Joshi
authors.forename: Mark L
authors.initials: ML
authors.lastname: Lang
mesh_terms: D000818:Animals; D000906:Antibodies / Q000097:blood / Q000276:immunology; D000917:Antibody Formation / Q000276:immunology*; D055610:Antigens, CD1d; D001402:B-Lymphocytes / Q000276:immunology*; D023201:CD40 Ligand / Q000276:immunology*; D008215:Lymphocytes, Null / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D055611:Natural Killer T-Cells / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology
chemical_list: D000906:Antibodies; D055610:Antigens, CD1d; D023201:CD40 Ligand