Antibody-mediated in vitro growth inhibition of field isolates of Plasmodium falciparum from asymptomatic children in Burkina Faso.
Antibody-mediated inhibition of Plasmodium falciparum parasites in vitro reflects the potential parasite-neutralizing activity of the antibodies in vivo. In this study, immunoglobulins and P. falciparum isolates were collected from children with asymptomatic malaria in Burkina Faso. We demonstrate a significantly lower in vitro growth inhibitory activity against the P. falciparum field isolates by autologous host immunoglobulin compared with that of immunoglobulin from other individuals. To gain further insight to possible mechanisms for the diverse sensitivity observed, analyses of consecutive isolates taken 14 days apart were performed with regard to polymerase chain reaction-based genotyping and sensitivity to growth inhibition in vitro. All the asymptomatic infections were composed of multiple, genotypically distinct parasite clones, and at least one new parasite clone appeared in most of the day 14 isolates compared with the corresponding day 0 isolates. Apparently persisting parasite clones, present in both the day 0 and day 14 isolates from the same person, were also frequently observed. The day 14 isolates were more effectively inhibited by autologous day 14 immunoglobulin than by the corresponding day 0 immunoglobulin in 57% of the cases. However, the frequent presence of persisting parasite clones in asymptomatic children indicates that the parasite may develop a relative resistance to neutralizing immune responses.
Bolad
Ahmed
A
Department of Immunology, Stockholm University, Stockholm, Sweden.
Nebié
Issa
I
Cuzin-Ouattara
Nadine
N
Traore
Alfred
A
Esposito
Fulvio
F
Berzins
Klavs
K
D000017:ABO Blood-Group System; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood / Q000276:immunology*; D000953:Antigens, Protozoan; D002050:Burkina Faso; D002648:Child; D002675:Child, Preschool; D016054:DNA, Protozoan / Q000032:analysis; D005838:Genotype; D006801:Humans; D007136:Immunoglobulins / Q000097:blood / Q000276:immunology*; D016778:Malaria, Falciparum / Q000276:immunology / Q000469:parasitology*; D018512:Parasitemia / Q000276:immunology / Q000469:parasitology; D010963:Plasmodium falciparum / Q000145:classification / Q000235:genetics / Q000254:growth & development* / Q000276:immunology*; D016133:Polymerase Chain Reaction
D000017:ABO Blood-Group System; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D016054:DNA, Protozoan; D007136:Immunoglobulins