IgG against Plasmodium falciparum variant surface antigens and growth inhibitory antibodies in Mozambican children receiving intermittent preventive treatment with sulfadoxine-pyrimethamine.
This study aimed to evaluate whether intermittent preventive treatment in infants with sulfadoxine-pyrimethamine (IPTi-SP) had an effect on the acquisition of IgG against Plasmodium falciparum variant surface antigens (VSA) and growth-inhibitory antibodies in Manhiça, Mozambique. In addition, we assessed factors affecting the magnitude of these responses and the association between antibody levels and protection against malaria. IgG to VSA expressed by MOZ2, R29 and E8B parasite isolates were measured in plasma samples collected at 5, 9, 12 and 24 months of age by flow cytometry. Growth-inhibitory antibodies in dialyzed plasmas using GFP-D10 parasites were measured by flow cytometry at 12 and 24 months. IPTi-SP did not significantly modify the levels of IgG against VSA nor the growth-inhibitory capacity of antibodies up to 2 years of age. Age but not previous episodes of malaria influenced the magnitude of these responses. In addition, anti-VSA IgG levels were 7% higher in children with current P. falciparum infection and were associated with neighborhood of residence. Children aged 24 months had 10% less parasite growth than those aged 12 months (95% CI 0.88-0.93, P<0.0001). Growth-inhibitory antibodies correlated with levels of IgG against AMA-1, when evaluating the 10% (R(2)=0.444, P=0.049) and 20% (R(2)=0.230, P=0.037) highest inhibitory samples. None of the responses were associated with subsequent risk of malaria. In conclusion, IPTi-SP does not negatively affect the development of antibody responses thought to be major contributors to the acquisition of immunity to malaria in infancy.
Centro de Investigação em Saúde da Manhiça, Manhiça, Mozambique.
Diana
D
Quelhas
Alfons
A
Jiménez
Llorenç
L
Quintó
Elisa
E
Serra-Casas
Alfredo
A
Mayor
Pau
P
Cisteró
Laura
L
Puyol
Danny W
DW
Wilson
Jack S
JS
Richards
Tacilta
T
Nhampossa
Eusebio
E
Macete
Pedro
P
Aide
Inacio
I
Mandomando
Sergi
S
Sanz
John J
JJ
Aponte
Pedro L
PL
Alonso
James G
JG
Beeson
Clara
C
Menéndez
Carlota
C
Dobaño
D000367:Age Factors; D000913:Antibodies, Protozoan / Q000097:blood; D000917:Antibody Formation / Q000187:drug effects; D000940:Antigenic Variation; D000953:Antigens, Protozoan / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology*; D004338:Drug Combinations; D006131:Growth Inhibitors / Q000097:blood; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D007231:Infant, Newborn; D016778:Malaria, Falciparum / Q000097:blood / Q000453:epidemiology / Q000276:immunology* / Q000517:prevention & control; D008565:Membrane Proteins / Q000276:immunology*; D009073:Mozambique; D010963:Plasmodium falciparum / Q000254:growth & development / Q000276:immunology* / Q000472:pathogenicity; D015800:Protozoan Proteins / Q000276:immunology*; D011739:Pyrimethamine / Q000008:administration & dosage*; D013413:Sulfadoxine / Q000008:administration & dosage*
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D000954:Antigens, Surface; D004338:Drug Combinations; D006131:Growth Inhibitors; D007074:Immunoglobulin G; D008565:Membrane Proteins; D015800:Protozoan Proteins; C090077:apical membrane antigen I, Plasmodium; C001205:fanasil, pyrimethamine drug combination; D013413:Sulfadoxine; D011739:Pyrimethamine