Immune responses in congenic mice to multiple antigen peptides based on defined epitopes from the malaria antigen Pf332

Abstract

SUMMARYRepeat sequences from the Plasmodium falciparum blood stage antigen Pf 332 frequently comprise the pentapeptide VTEEI, an epitope recognized by certain parasite neutralizing antibodies. This B-cell epitope was assembled in an octavalent multiple antigen peptide (MAP) system either as trimers (VTEEI) 3 (MAP1) or as an integral part of a naturally occurring Pf332 undecamer repeat sequence SVTEEIAEEDK (MAP2). Characteristics of the immunogenicity of these subunit constructs were evaluated in H-2 congenic mice. MAP1 generated antibody responses in mice of the H-2 d , H-2 k and H-2 q haplotypes, but not in H-2 b or H-2 s mice, whereas MAP2 only induced antibodies in mice of H-2 k haplotype. When analysing T-cell responses induced by the MAP, lymph node cells from responder strains primed in vivo with MAP1 proliferated in response to restimulation with both MAP1 and the peptide (VTEEI) 3 . MAP2, however, did not induce a detectable T-cell proliferation. Additionally, the lack of antibody response to MAP1 in H-2 b mice could be circumvented by combining the MAP1 peptide and a H-2 b -restricted T-cell epitope in a diepitope MAP construct. Despite the fact that the motif VTEEI has not been identified in Pf332 sequences in the form of a trimer, MAP1 did induce Pf332 proteinreactive antibodies. Assembly of multimers of short defined epitopes in MAP constitutes an interesting approach for the design of polyvalent subunit immunogens.

Solid‐phase dendrimer synthesis

“…In a ([Lys] 4 -[Lys] 2 -Lys) MAP conjugated to a 15-mer peptide, the peptide is responsible for greater than 90% of the total mass of the MAP; significantly, the branching Lys core is immunologically inactive, 11,12 suggesting inaccessibility. MAPS have been used very effectively in eliciting immunogenic responses against malaria antigens in rodents, [13][14][15][16][17][18][19][20] as diagnostic tools, [21][22][23] and for the treatment of AIDS-promoted maladies. 24 MAPS can produce an immune response equivalent to highly concentrated monomeric preparations 25 and each dendritic core is also able to effectively present up to two or three peptide sequences.…”

“…Mass spectra were obtained on a VG Platform single quadrupole mass spectrometer in Electrospray positive ionization mode, and where necessary were processed by MaxEnt 61,62 to convergence. Analytical RP-HPLC was performed on a Hewlett Packard HP1100 system equipped with a Phenomenex Prodigy C 18 Amino acids and peptide coupling agents were purchased from Novabiochem. TentaGel resin (0.30 mmol/g wrt -NH 2 groups) was obtained from Rapp Polymere Laboratories.…”

Solid-phase dendrimer synthesis

“…The multiple antigen peptide system (MAPS), first described by Tam in 1988, 9 comprises a central carrier core made up of sequential levels of lysine and an outer region of peptide antigens, 10 such that the construction affords a high density of peptide antigens. MAPS have been used very effectively in eliciting immunogenic responses against malaria antigens in rodents, [13][14][15][16][17][18][19][20] as diagnostic tools, [21][22][23] and for the treatment of AIDS-promoted maladies. In a ([Lys] 4 -[Lys] 2 -Lys) MAP conjugated to a 15-mer peptide, the peptide is responsible for greater than 90% of the total mass of the MAP; significantly, the branching Lys core is immunologically inactive, 11,12 suggesting inaccessibility.…”

Developing Novel Immunogens for an Effective, Safe Alzheimer’s Disease Vaccine

“…Dendrimeric peptides are generated by the synthesis of antigens onto a branched lysine tree resulting in a high molecular weight antigen with multiple antigenic sites ( fi g. 1 a). Dendrimeric peptides have been used suc- cessfully in rodents to produce an immune response against malaria [42,43] , human immunodefi ciency virus [44] and gliomas [45] , amongst others. The repeated copies of the antigen may overcome immunological tolerance as suggested by the lowered humoral immune response reported in APP TG mice [37] .…”