Kappa and lambda light chain composition of antibody to the capsular polysaccharide of Haemophilus influenzae type b.

Concentrations of total immunoglobulins bearing kappa and lambda light chains were measured in the sera of 215 healthy white children aged 6 months to 10 years. Both kappa and lambda concentrations increased with age. However, the concentration of immunoglobulins bearing kappa light chains increased at a greater rate than those bearing lambda light chains (P = .01). Thus, the kappa:lambda ratio of the youngest children (6-24 months) was significantly lower than that of the oldest (25-130 months) (P = .0015). The relationship between the IgG antibody concentration and the light chain composition of the specific antibody directed to Haemophilus influenzae type b (Hib) polysaccharide was also assessed in 62 of 215 serum samples with detectable Hib antibody. The IgG Hib antibody concentration was strongly correlated with the kappa:lambda Hib antibody ratio (r = .60, P = .001), and this correlation was independent of age. Thus, light chain selection and response to polysaccharides may be regulated by common mechanisms that mature late in ontogeny.