[IgG responses to candidate malaria vaccine antigens in the urban area of Dakar (Senegal): evolution according to age and parasitemia in patients with mild symptoms].
Malaria remains a major problem in African countries despite substantial decreases in morbidity and mortality due to sustained control programs. Studies for the evaluation of qualitative or quantitative Ab responses to key targets of anti-plasmodium immunity were mostly done in rural endemic setting compared to urban area. In a cohort of 200 patients with mild malaria and living in Dakar, we analyze total and subclasses IgG responses to a panel of P. falciparum blood stage antigens: MSP1p19, MSP3, EB200, GST-5 and R23. A mean age of 15 yrs (4 to 56 yrs) and parasitemia between 0.1 to 17% were found. Levels of IgG anti-MSP3 were higher in patients with low parasitemia (≤1%) and appear negatively correlated to parasite densities (Rho =. 0.54; p= 0.021). This correlation is more significant in children (≤ 15 yrs). In addition, an increase of IgG responses against MSP1p19 is highly observed in adults having a parasitemia less than 1%. In those patients, we find that IgG1 subclasses were predominant (p <0.01). Our study shows an association between Ab responses and parasitemia. This association is dependant to IgG anti-MSP3 in children and IgG anti-MSP1p19 in adults living in urban area.
Service d'immunologie UCAD FMPO, Dakar, Sénégal, bmbengue@pasteur.sn.
B
B
Mbengue
M
M
Sylla Niang
R
R
Ndiaye Diallo
G
G
Diop
A
A
Thiam
O
O
Ka
A
A
Touré
A
A
Tall
R
R
Perraut
A
A
Dièye
D000293:Adolescent; D000328:Adult; D000375:Aging / Q000097:blood / Q000276:immunology*; D000953:Antigens, Protozoan / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D017780:Malaria Vaccines / Q000276:immunology*; D016778:Malaria, Falciparum / Q000097:blood / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D018512:Parasitemia / Q000097:blood / Q000453:epidemiology* / Q000276:immunology; D010963:Plasmodium falciparum / Q000276:immunology*; D012675:Senegal / Q000453:epidemiology; D012720:Severity of Illness Index; D014505:Urban Population / Q000706:statistics & numerical data; D055815:Young Adult
D000953:Antigens, Protozoan; D007074:Immunoglobulin G; D017780:Malaria Vaccines