title: Phosphocholine-Specific Antibodies Improve T-Dependent Antibody Responses against OVA Encapsulated into Phosphatidylcholine-Containing Liposomes.
abstract: Liposomes containing phosphatidylcholine have been widely used as adjuvants. Recently, we demonstrated that B-1 cells produce dipalmitoyl-phosphatidylcholine (DPPC)-specific IgM upon immunization of BALB/c mice with DPPC-liposomes encapsulating ovalbumin (OVA). Although this preparation enhanced the OVA-specific humoral response, the contribution of anti-DPPC antibodies to this effect was unclear. Here, we demonstrate that these antibodies are secreted by B-1 cells independently of the presence of OVA in the formulation. We also confirm that these antibodies are specific for phosphocholine. The anti-OVA humoral response was partially restored in B-1 cells-deficient BALB/xidmice by immunization with the liposomes opsonized with the serum total immunoglobulin (Ig) fraction containing anti-phosphocholine antibodies, generated in wild-type animals. This result could be related to the increased phagocytosis by peritoneal macrophages of the particles opsonized with the serum total Ig or IgM fractions, both containing anti-phosphocholine antibodies. In conclusion, in the present work, it has been demonstrated that phosphocholine-specific antibodies improve T-dependent antibody responses against OVA carried by DPPC-liposomes.
authors.affiliation: Laboratory of Toxins and Liposomes, Center for Protein Studies (CEP), Faculty of Biology, University of Havana , Havana , Cuba.
authors.forename: Yoelys
authors.initials: Y
authors.lastname: Cruz-Leal
authors.affiliation: Immunobiology Direction, Center of Molecular Immunology (CIM) , Havana , Cuba.
authors.forename: Alejandro
authors.initials: A
authors.lastname: López-Requena
authors.affiliation: Biochemistry Department, Faculty of Biology, University of Havana , Havana , Cuba.
authors.forename: Isbel
authors.initials: I
authors.lastname: Lopetegui-González
authors.affiliation: Development Direction, Center of Molecular Immunology (CIM) , Havana , Cuba.
authors.forename: Yoan
authors.initials: Y
authors.lastname: Machado
authors.affiliation: Laboratory of Toxins and Liposomes, Center for Protein Studies (CEP), Faculty of Biology, University of Havana , Havana , Cuba.
authors.forename: Carlos
authors.initials: C
authors.lastname: Alvarez
authors.affiliation: Immunobiology Direction, Center of Molecular Immunology (CIM) , Havana , Cuba.
authors.forename: Rolando
authors.initials: R
authors.lastname: Pérez
authors.affiliation: Laboratory of Toxins and Liposomes, Center for Protein Studies (CEP), Faculty of Biology, University of Havana , Havana , Cuba.
authors.forename: María E
authors.initials: ME
authors.lastname: Lanio
keywords: B-1 cells; humoral response; liposomes; peritoneal macrophages; phosphocholine-specific antibodies