Immunization with SPf66 and subsequent infection with homologous and heterologous Plasmodium falciparum parasites.
Am J Trop Med Hyg
; 59(4): 600-5, 1998 Oct.
Article
en En
| MEDLINE
| ID: mdl-9790438
ABSTRACT
In an area of intense transmission, a malaria vaccine could reduce infection due to the parasite types represented in the vaccine, but have no detectable effect on the overall frequency of infection if it did not protect against infection with heterologous parasites. These studies were performed to determine whether immunization with SPf66 decreased infection with homologous parasites containing the 11 amino acid peptide from merozoite surface protein-1 (MSP-1) in SPf66, or increased infection due to heterologous parasites containing heterologous (alternative) MSP-1 sequences. Based on this 11 amino acid peptide (YSLFQKEKMVL), three forward primers (S,Q,V) were designed to amplify the MSP-1 sequence present in SPf66, and 3 additional forward primers (G,H,I) to amplify the alternative MSP-1 sequence (YGLFHKEKMIL). This strategy was validated by polymerase chain reaction (PCR) amplification and dideoxy sequencing with 14 cloned laboratory isolates, which demonstrated that each primer amplified one MSP-1 sequence or the other, but not both. The technique was then used to examine filter paper blots from an SPf66 vaccine study of 69 subjects in Saradidi, Kenya. In that study, the prevalence of infection with YSLFQKEKMVL or YGLFHKEKMIL type parasites was unaffected by immunization with SPf66 (based on PCR amplification with the S, Q, V, G, H and I primers, respectively). These results suggest that immunization with SPf66 does not produce a selective effect in vivo. They demonstrate a molecular method to test for selection in vivo as an indirect measure of vaccine efficacy.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Fragmentos de Péptidos
/
Plasmodium falciparum
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Vacunas Sintéticas
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Malaria Falciparum
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Proteína 1 de Superficie de Merozoito
Tipo de estudio:
Clinical_trials
/
Risk_factors_studies
Límite:
Adolescent
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Adult
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Animals
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Humans
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Middle aged
Idioma:
En
Revista:
Am J Trop Med Hyg
Año:
1998
Tipo del documento:
Article