Immunity to schistosomiasis before puberty: humeral or cell mediated.
To determine if the cell mediated immunity, induced by T-helper type-1 lymphocytes (Th1) response, during schistosomiasis mansoni has the potential to protect against infection, intensities of infections and re-infections, reflected in the egg count were followed up to 20 months among 119 individuals aged 5-22 years (Ys) with different number of previous infections whose yearly levels and pattern of water contact were similar. They were classified into 5 groups. Delayed hypersensitivity skin tests (DHT) to adult schistosome excretory-secretary antigens (ESAgs) and anti-schistosomula (ESAgs) isotypes were measured on detecting re-infection. The group with a mean age of (8.6 +/- 2.6 Ys) and infected less than 5 times showed only 6.5 percentage reduction of the egg count (PREC) and low cellular and humoral responses. Th1-associated cellular (DHT) and antibody responses (IgG2, IgG3) to the five infections were significantly higher in the (13.5 +/- 1.4 Ys) than in (18 +/- 2.2 Ys) age group. This was reflected in significant difference in PREC; being 41.5% among the first and 13.5% among the second. Th2-associated antibody responses (IgG1, IgG4, IgE) went on rising as patients allowed for age and number of infections increased over 5, being significantly higher in the (19 +/- 1.8 Ys) than in (14 +/- 1.1 Ys) age groups with PREC 45.5% and 12.9% respectively. These results imply a substantial protective role for cell mediated immunity in the pre-puberty stage and provide evidence that Th1-based vaccination strategy can work if augmented.
Abdel-Fattah
M M
MM
Department of Parasitology, Faculty of Medicine, Zagazig University, Zagazig, Egypt.
el-Gindy
A E
AE
Hegab
M H
MH
el-Mohammed
F
F
Shahin
A M
AM
el-Gohary
F
F
Omar
O M
OM
Khater
N
N
D000293:Adolescent; D000328:Adult; D000375:Aging / Q000276:immunology*; D000818:Animals; D000909:Antibodies, Helminth / Q000302:isolation & purification; D000917:Antibody Formation / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D004534:Egypt; D005243:Feces / Q000469:parasitology; D005260:Female; D006801:Humans; D007111:Immunity, Cellular / Q000276:immunology*; D008297:Male; D010270:Parasite Egg Count; D011627:Puberty / Q000502:physiology*; D012550:Schistosoma mansoni / Q000276:immunology; D012555:Schistosomiasis mansoni / Q000276:immunology*
D000909:Antibodies, Helminth