title: Macrophages pulsed with Streptococcus pneumoniae elicit a T cell-dependent antibody response upon transfer into naive mice.
abstract: Macrophages are less effective than DC at priming naive CD4(+) T cells, suggesting that DC are unique in initiating T cell-dependent Ab responses. We compared the ability of DC and macrophages, pulsed in vitro with Streptococcus pneumoniae, to elicit protein- and polysaccharide-specific Ig isotype production upon adoptive transfer into naive mice. S. pneumoniae-activated DC secreted more proinflammatory and anti-inflammatory cytokines, expressed higher levels of surface MHC class II and CD40, and presented S. pneumoniae or recombinant pneumococcal surface protein A (PspA) to a PspA-specific T hybridoma more efficiently than macrophages. However, upon adoptive transfer into naive mice, S. pneumoniae-pulsed macrophages elicited an IgM or IgG anti-PspA and anti-polysaccharide response comparable in serum titers and IgG isotype distribution to that induced by DC. The IgG anti-PspA response, in contrast to the IgG anti-polysaccharide, to S. pneumoniae-pulsed macrophages was T cell-dependent. S. pneumoniae-pulsed macrophages that were paraformaldehyde-fixed before transfer or lacking expression of MHC class II or CD40 were highly defective in eliciting an anti-PspA response, although the anti-polysaccharide response was largely unaffected. To our knowledge, these data are the first to indicate that macrophages can play an active role in the induction of a T cell-dependent humoral immune response in a naive host.
authors.affiliation: Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.
authors.forename: Sam
authors.initials: S
authors.lastname: Vasilevsky
authors.forename: Jesus
authors.initials: J
authors.lastname: Colino
authors.forename: Roman
authors.initials: R
authors.lastname: Puliaev
authors.forename: David H
authors.initials: DH
authors.lastname: Canaday
authors.forename: Clifford M
authors.initials: CM
authors.lastname: Snapper
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D000906:Antibodies / Q000276:immunology*; D000938:Antigen-Presenting Cells / Q000276:immunology; D001426:Bacterial Proteins / Q000276:immunology; D001853:Bone Marrow / Q000276:immunology; D002454:Cell Differentiation / Q000276:immunology; D002478:Cells, Cultured; D016207:Cytokines / Q000276:immunology / Q000378:metabolism; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D007113:Immunity, Innate / Q000276:immunology*; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D010587:Phagocytosis / Q000276:immunology; D010641:Phenotype; D013296:Streptococcus pneumoniae / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000906:Antibodies; D001426:Bacterial Proteins; D016207:Cytokines; C051592:pneumococcal surface protein A