Expression of filarial-specific IgG subclasses under different transmission intensities in a region endemic for loiasis

• Published in: The American journal of tropical medicine and hygiene Vol. 66; no. 3; pp. 245 - 250
• Main Authors: Akue, JP, Devaney, E, Wahl, G, Moukana, H
• Format: Journal Article
• Language: English
• Published: Lawrence, KS ASTMH 01.03.2002; Allen Press
• Subjects: Animals; Antibodies, Helminth - blood; Antibody Specificity; Antigens, Helminth - immunology; Biological and medical sciences; Diptera; Diseases caused by nematodes; Endemic Diseases; Enzyme-Linked Immunosorbent Assay; Filariases; Gabon - epidemiology; Helminthic diseases; Immunoglobulin G - blood; Immunoglobulin G - classification; Infectious diseases; Insect Vectors; Larva - immunology; Loa - growth & development; Loa - immunology; Loaiasis; Loiasis - epidemiology; Loiasis - parasitology; Loiasis - transmission; Medical sciences; Parasitic diseases; Rural Population; Tropical medicine; Gabon; Human; Immune response; Transmission; IgG; Variations; Parasitosis; Helminthiasis; Loaiasis; Infection; Specificity; Immunological investigation; Nematode disease; Filariosis; Humoral immunity
• ISSN: 0002-9637; 1476-1645
• DOI: 10.4269/ajtmh.2002.66.245

Specific IgG subclasses were investigated in two villages (Okoumbi and Ndjokaye) in southeast Gabon with different Loa loa transmission intensities of approximately 9,000 and 1,300 infective larvae (L3) per person per year, respectively. IgG subclasses were measured by an enzyme-linked immunosorbent assay (ELISA) using extracts of L. loa L3, microfilariae (MF), or adult worms. Levels of L3-specific IgG3 were significantly higher in the village with low transmission (Ndjokaye) (P = 0.006). In contrast, MF-specific IgG2 was significantly higher in Okoumbi than in Ndjokaye (P = 0.0009). In the high-transmission village (Okoumbi), levels of both MF- and adult-specific IgG4 were significantly increased in MF carriers compared with amicrofilaremic subjects (P = 0.0015 and P = 0.003, respectively), while levels of L3- and MF-specific IgG1 were significantly higher in amicrofilaremic individuals compared with MF carriers (P = 0.04 and P = 0.03, respectively). Furthermore, among microfilaremic individuals, the level of the specific IgG1 subclass was much lower in Okoumbi than in Ndjokaye (P = 0.036). These results suggest that the expression of antigen-specific IgG3 and IgG2 is more likely to vary with transmission intensity, whereas antigen-specific IgG4 and IgG1 varies with adult worm and MF burden.