Abstract:
Peptideslinked to carrier proteins are widely used to produce anti-peptide antibodies
for experimentalpurposes. Since peptide vaccines are relatively inexpensive and antipeptideantibodiesare able to react specifically with the corresponding native protein
in manyinstances,there is considerable interest in using peptide-carrier conjugates as
vaccines against human and veterinary diseases including malaria. Peptides
correspondingto known and predicted Band T cell epitopes of the antigens of human
malaria parasite Plasmodium falciparum were synthesized. A 45kDa merozoite
surfaceglycoprotein(GYMSSA), a precursor to the major merozoite surface antigen
(PMMSA),an antigen present in the rhoptry-microneme complex (RAP), a serine rich
antigen (SERA) present largely in the parasitophorous vacuole and a protein
containing acidic and basic amino acid repeats also present largely in the
parasitophorousvacuole (ABRA) were used in the study. The studies were performed
in four stages. Firstly, peptides from GYMSSA and PMMSA were conjugated
through6-maleimido caproic acyl N-succinimide ester to bovine serum albumin. The
conjugateswere used to immunize Balb/c mice in saline and with different adjuvants.
Freund's adjuvant, two muramyl dipeptide derivatives (murabutide and muramatide)
andaluminiumhydroxide. Three injections of antigen were given intra muscularly at
2ld intervals and sera obtained after each injection. Antibody levels against peptides
were measured by ELISA. Freund's adjuvant produced the highest titer of 10-4.
Antibody levels obtained with alum absorbed antigen reached titers of 10-3- 10-4
while antigen administered in saline alone yielded titers of 10-3. The synthetic
adjuvantsmaramyl dipeptide derivatives did not produce higher antibody levels than
