A prospective study of the association between the human humoral immune response to Plasmodium falciparum blood stage antigen gp190 and control of malarial infections

Abstract

The human humoral immune response to the Plasmodium falkiparum merozoite surface antigen gpl90 was analyzed to determine the rate of reinfection by the parasite and the ability to control parasite density. The prospective study was carried out in a West African village where malaria is hyperendemic. No correlation between the antibody titers and protection against infection was observed within the group of children. Positive and negative associations of antibody specificities with protection against and/or control of parasitemia were, however, found for adolescents and adults, respectively. Thus, in adolescents, the presence of antibodies to gpl90 fragment M6 correlates with a 50%v reduced risk of P. falciparum infection and an increased ability to control parasitemia, whereas in adults, the humoral response to some of the polymorphic regions of gpl90 associates with an increased risk of infection.

Analysis of the human antibody response to thrombospondin-related anonymous protein of Plasmodium falciparum

“…All donors received a curative dose of chloroquine consisting of 25 mg/kg of body weight on 3 subsequent days starting on day 0 of the study (23 May 1989) before the onset of malaria transmission. At this time, chloroquine resistance was absent in the study area (34). Blood smears on day 7 served as indicators of successful treatment.…”

“…Entomological inoculation rates (infective bites per person per night) were monitored by using the spray catch method (36,37). Detailed descriptions of the study area have been published previously (11,34). The study was approved by the National Ethical Committee of the Ministry of Health of Mali.…”

“…A total of 193 volunteers aged 2 to 81 years were enrolled in the survey upon informed consent; in the cases of children under 18 years of age, consent of the parents or guardians was obtained. For 186 of these individuals the hemoglobin genotype had been determined previously (34). All donors received a curative dose of chloroquine consisting of 25 mg/kg of body weight on 3 subsequent days starting on day 0 of the study (23 May 1989) before the onset of malaria transmission.…”

“…Thick and thin blood smears were prepared in the field from finger pricks on day 0 before the antimalaria treatment, on day 7, on day 14, and every 2 weeks thereafter until day 208 (29 December 1989). After smears were stained with Giemsa stain, parasitemia was evaluated by counting infected versus noninfected erythrocytes in fields containing 300 leukocytes (34). Serum samples were collected on days 0 and 208, as described previously (34).…”

Genetic diversity of Plasmodium falciparum merozoite surface protein‐1 (block 2), glutamate‐rich protein and sexual stage antigen Pfs25 from Chandigarh, North India

“…It is 1720 amino acids long divided into 17 blocks, which are of variable, conserved or semi‐conserved nature . Block 2 of msp1 is highly variable and presents three allelic families: K1, MAD20 and RO33, while the remaining 16 blocks are dimorphic . Plasmodium falciparum glutamate‐rich protein ( pfglurp ) is expressed on erythrocytic and pre‐erythrocytic stages of the parasite and also on the newly released merozoite .…”