Antibody response to polyhistidine-tagged peptide and protein antigens attached to liposomes via lipid-linked nitrilotriacetic acid in mice.
Clin Vaccine Immunol
; 18(2): 289-97, 2011 Feb.
Article
em En
| MEDLINE
| ID: mdl-21159923
ABSTRACT
Particulate delivery systems enhance antibody responses to subunit antigens. However, covalent attachment of protein antigens can disrupt protein structure and mask critical epitopes, altering the antibody response to the antigen. In this report, we evaluate noncovalent metal chelation via nitrilotriacetic acid (NTA) as a nondestructive method to attach peptide and protein antigens to liposomes. Two model antigens, ovalbumin (OVA) and a peptide derived from the membrane-proximal region of HIV-1 gp41 (N-MPR), were polyhistidinylated and attached to liposomes via monovalent NTA (mono-NTA; K(D) [equilibrium dissociation constant], â¼10 µM), trivalent NTA (tris-NTA; K(D), â¼1 nM), or a covalent linkage. Attachment of N-MPR, but not OVA, to liposomes via an NTA lipid elicited stronger antibody responses in BALB/c mice than a formulation in which unassociated antigen was simply admixed with control liposomes lacking NTA. However, the tris-NTA linkage did not increase antibody responses to either N-MPR or OVA compared to the level for the mono-NTA linkage, despite the greater liposomal association of the antigen. For both antigens, covalently attaching them to a lipid elicited significantly stronger antibody responses than NTA-anchored antigens (OVA titer, 3.4 × 10(6) versus 1.4 × 10(6) to 1.6 × 10(6) [P < 0.001]; N-MPR titer, 4.4 × 10(4) versus 5.5 × 10(2) to 7.6 × 10(2) [P < 0.003]). The data indicate that NTA linkages may increase antibody titers to weak antigens such as N-MPR, but NTA-mediated attachment remains inferior to covalent conjugation. Moreover, enhancements in antigen-liposome affinity do not result in increased antibody titers. Thus, additional improvements of NTA-mediated conjugation technology are necessary to achieve an effective, nondestructive method for increasing the humoral response to antigens in particulate vaccines.
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Peptídeos
/
Adjuvantes Imunológicos
/
Histidina
/
Lipossomos
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Anticorpos
/
Antígenos
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Ácido Nitrilotriacético
Limite:
Animals
Idioma:
En
Revista:
Clin Vaccine Immunol
Assunto da revista:
ALERGIA E IMUNOLOGIA
/
TECNICAS E PROCEDIMENTOS DE LABORATORIO
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
Estados Unidos