Antibody response to polyribosyl-ribitol phosphate antigen of Haemophilus influenzae in Ecuadorian and German children.
Serum samples from 1,221 Ecuadorian children 0 to 5 years of age and from 236 German subjects were tested by enzyme-linked immunosorbent assay for class-specific antibodies to the capsular polysaccharide of Haemophilus influenzae type b (PRP antigen). A gradual prevalence increase of and mean titer increase in immunoglobulin M (IgM) antibody was seen in Ecuadorian but not in German children older than 6 months. At the end of the first year of life, about 50% of the Ecuadorian children showed IgM and IgG antibody to PRP. Seroepidemiological analysis revealed that living at a low altitude and lower calorie intake (a proxy measure of breast-feeding) were factors associated with earlier acquisition of PRP antibody. Children from low-altitude areas of Ecuador also experienced significantly more episodes of significant respiratory infections. The acquisition of PRP-reactive antibodies in Ecuadorian children might thus reflect exposure to encapsulated H. influenzae type b in lower respiratory tract infections.
D000907:Antibodies, Bacterial / Q000096:biosynthesis* / Q000097:blood; D002675:Child, Preschool; D004484:Ecuador / Q000453:epidemiology; D005260:Female; D005858:Germany / Q000453:epidemiology; D006192:Haemophilus Infections / Q000453:epidemiology / Q000276:immunology; D006193:Haemophilus influenzae / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000097:blood; D007075:Immunoglobulin M / Q000096:biosynthesis / Q000097:blood; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011134:Polysaccharides / Q000276:immunology*; D011135:Polysaccharides, Bacterial / Q000276:immunology*
D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011134:Polysaccharides; D011135:Polysaccharides, Bacterial; C008984:polyribitol phosphate