ABSTRACT
To evaluate the usefulness of pH-sensitive fusogenic polymer (succinylated poly(glycidol) (SucPG) and 3-methylglutarylated poly(glycidol) (MGluPG))-modified liposomes as mucosal vaccine in the induction of a protective immune responses was evaluated. Mice were nasally immunized with OVA-containing SucPG-modified liposomes. After immunization, significant Ag-specific Abs were detected in the serum and intestine. When sera were analyzed for isotype distribution, antigen-specific IgG1 Ab responses were noted in mice immunized with OVA-containing polymer-unmodified liposomes, whereas immunization with OVA-containing SucPG-modified liposomes resulted in the induction of OVA-specific IgG1, IgG2a and IgG3 Ab responses. In spleen lymphocytes from mice immunized with OVA-containing SucPG-modified liposomes, both IFN-γ and IL-4 mRNA were detected. The same result was obtained also in the mouse immunized with OVA-containing MGluPG-modified liposomes. Furthermore, we examined the induction of immune responses in chickens following intraocular immunization with Salmonella Enteritidis Ag-containing MGluPG-modified liposomes, and the protective effect against the challenge with S. Enteritidis. Immunization with S. Enteritidis Ag-containing MGluPG-modified liposomes induced significant Ab responses against S. Enteritidis in the serum and intestine. Less fecal excretion of bacteria was observed in chickens immunized with S. Enteritidis Ag-containing MGluPG-modified liposomes after challenge. The numbers of bacteria in the caecum were also lower in immunized chickens than in unimmunized controls.
Subject(s)
Chickens , Liposomes/pharmacology , Poultry Diseases/microbiology , Salmonella Infections, Animal/microbiology , Salmonella Vaccines/pharmacology , Salmonella enteritidis/immunology , Animals , Feces/microbiology , Female , Immunization/veterinary , Immunoglobulin G/blood , Interferon-gamma/blood , Interferon-gamma/genetics , Interleukin-4/blood , Interleukin-4/genetics , Mice , Mice, Inbred BALB C , Nasal Mucosa/immunology , Nasal Mucosa/microbiology , Poultry Diseases/immunology , Propylene Glycols/pharmacology , RNA, Messenger/chemistry , RNA, Messenger/genetics , Reverse Transcriptase Polymerase Chain Reaction/veterinary , Salmonella Infections, Animal/blood , Salmonella Infections, Animal/immunology , Salmonella Infections, Animal/prevention & control , Specific Pathogen-Free OrganismsABSTRACT
The usefulness of pH-sensitive fusogenic polymer-(succinylated poly(glycidol)-(SucPG-) modified liposomes as a vaccine carrier in the induction of immune responses was evaluated. Mice were intraperitoneally immunized with ovalbumin- (OVA-) containing SucPG-modified liposomes. After immunization, significant OVA-specific antibodies were detected in the serum. When sera were analyzed for isotype distribution, OVA-specific IgG1 antibody responses were noted in mice immunized with OVA-containing polymer-unmodified liposomes, whereas immunization with OVA-containing SucPG-modified liposomes resulted in the induction of OVA-specific IgG1, IgG2a, and IgG3 Ab responses. In spleen lymphocytes from mice immunized with OVA-containing SucPG-modified liposomes, both IFN-γ-(Th1-type-) and IL-4-(Th2 type-) specific mRNA were detected. Moreover, substantial production of IFN-γ and IL-4 was demonstrated in spleen cells from OVA-containing SucPG-modified liposomes in vitro. These results suggest that the pH-sensitive fusogenic polymer-(SucPG-) modified liposomes would serve effectively as an antigen delivery vehicle for inducing Th1 and Th2 immune responses.
