title: Correlation between antibody affinity and serum bactericidal activity in infants.
abstract: Nearly one-half of infants immunized with Haemophilus influenzae b capsular polysaccharide (polyribosylribitol phosphate; PRP)-protein conjugate produce low-affinity antibody. To test the hypothesis that antibody affinity is linked to biologic function, sera were obtained before and 1 month after immunization of 18-month-old infants with PRP-diphtheria toxoid conjugate vaccine. Correlation was attempted of anti-PRP affinity, concentrations of anti-PRP, and anti-outer membrane proteins and of immunoglobulin isotype with bactericidal activity. Nine subjects produced anti-PRP of low affinity (K less than 10(4) l/mol), and 11 had higher affinity antibodies (average K, 2.8 x 10(4) l/mol). By multiple regression analysis, antibody affinity was the only variable significantly related to the bactericidal activity of serum after immunization with the conjugate vaccine (r = .71; P = .04). Thus, serum anti-PRP from a substantial proportion of infants appeared functionally deficient in association with low-affinity antibody.
authors.affiliation: Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38101.
authors.forename: S V
authors.initials: SV
authors.lastname: Hetherington
authors.forename: M L
authors.initials: ML
authors.lastname: Lepow
mesh_terms: D000907:Antibodies, Bacterial / Q000096:biosynthesis / Q000097:blood* / Q000276:immunology; D001428:Bacterial Vaccines / Q000276:immunology*; D001770:Blood Bactericidal Activity; D004168:Diphtheria Toxoid / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D018073:Haemophilus Vaccines; D006801:Humans; D007114:Immunization; D007223:Infant; D011863:Radioimmunoassay; D012044:Regression Analysis
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D004168:Diphtheria Toxoid; D018073:Haemophilus Vaccines; C052180:Haemophilus influenzae type b-polysaccharide vaccine-diphtheria toxoid conjugate