Safety, immunogenicity and protective effect of the SPf66 malaria synthetic vaccine against Plasmodium falciparum infection in a randomized double-blind placebo-controlled field trial in an endemic area of Ecuador

Humoral Immune Response to the Anti-malaria Vaccine SPf66 in the Colombian Atrato River Region

“…The percentage of specific anti-peptide antibody carriers three months after the third dose in the SPf66 vaccinated group (63.1%) is similar to that reported in other studied populations in Ecuador (57%) (Sempertegui et al 1994) and Venezuela (60.4%) (Noya et al1994), but higher than that observed in a study carried out in La Tola (Colombia) (33%) (Valero et al 1993). This can be explained by the fact that in the latter study the cutoff point used for the determination of antibody titers was 0.2 (Valero et al 1993), unlike the 0.1 cutoff point used by the other studies (Sempertegui et al 1994, Noya et al 1994.…”

“…Vaccination -Individuals were immunized with the synthetic peptide SPf66, batch # 8, produced by the Instituto de Inmunología, Bogotá (Colombia) under good manufacturing practice, by means of the solid-phase chemical synthesis method (Houghten 1985, Valero et al 1993, Sempertegui et al 1994.…”

“…The peptide has been tested in animal models and human volunteers subject to experimental challenge (Patarroyo et al 1987(Patarroyo et al , 1988 as well as in individuals from endemic areas in Colombia and other countries in America and Africa (Valero et al 1993, Sempertegui et al 1994, Teuscher et al 1994.…”

“…SPf66 has been shown to induce production of specific IgG antibodies against the peptide in approximately 60% of vaccinees once immunization is completed, although such immunogenicity has not been associated to protection against malarial infections (Valero et al 1993, Sempertegui et al 1994, Teuscher et al 1994.…”

“…Immunogenicity of the SPf66 vaccine has been expressed in terms of the relative frequency of positive individuals for specific IgG antibodies against the peptide one month after completion of the immunization schedule (Valero et al 1993, Sempertegui et al 1994, Noya et al 1994. These antibodies are known to recognize native proteins in the merozoite such as 135Kd, 83 Kd and 115 Kd (Salcedo et al 1991).…”