H. Brussow et al., ANTIBODY-RESPONSE TO POLYRIBOSYL-RIBITOL PHOSPHATE ANTIGEN OF HAEMOPHILUS-INFLUENZAE IN ECUADORIAN AND GERMAN CHILDREN, Clinical and diagnostic laboratory immunology, 1(1), 1994, pp. 21-25
Serum samples from 1,221 Ecuadorian children 0 to 5 years of age and f
rom 236 German subjects were tested by enzyme-linked immunosorbent ass
ay for class-specific antibodies to the capsular polysaccharide of Hae
mophilus influenzae type b (PRP antigen). A gradual prevalence increas
e of and mean titer increase in immunoglobulin M (IgM) antibody was se
en in Ecuadorian but not in German children older than 6 months. At th
e end of the first year of life, about 50% of the Ecuadorian children
showed IgM and IgG antibody to PRP. Seroepidemiological analysis revea
led that living at a low altitude and lower calorie intake (a proxy me
asure of breast-feeding) were factors associated with earlier acquisit
ion of PRP antibody. Children from low-altitude areas of Ecuador also
experienced significantly more episodes of significant respiratory inf
ections. The acquisition of PRP-reactive antibodies in Ecuadorian chil
dren might thus reflect exposure to encapsulated H. influenzae type b
in lower respiratory tract infections.