title: A human IgG anti-Vi reference for Salmonella typhi with weight-based antibody units assigned.
abstract: Recent data showing the high incidence of typhoid fever in young children, the demonstration of safety and efficacy of a Vi conjugate for this age group, the safety and similar immunogenicity in infants when administrated concurrently with EPI vaccines, together with the interests of manufacturers and investigators in studying such conjugate vaccines prompted us to prepare a human IgG anti-Vi standard to facilitate this work. Volunteers were injected with an investigational Vi-recombinant Pseudomonas aeruginosa exoprotein A (Vi-rEPA) conjugate vaccine. Plasmas with the highest levels of IgG anti-Vi were pooled. The IgG anti-Vi content of this preparation, assayed by precipitin analysis with purified Vi, was 33 μg/ml. Accordingly, the estimated IgG anti-Vi protective level of 3.5 ELISA unit/ml, derived from our efficacy trial of Vi-rEPA in 2-5 years old children, is equivalent to 4.3 μg/ml. This reagent is suitable for comparison of immune response of Vi conjugate vaccines or for other purposes requiring anti-Vi measurement.
authors: Eunice Kennedy Shriver National Institute of Child Health & Human Development, National Institutes of Health, Bethesda, MD 20892, USA. szus@mail.nih.gov
authors: Shousun C
authors: SC
authors: Szu
authors: Steven
authors: S
authors: Hunt
authors: Guilin
authors: G
authors: Xie
authors: John B
authors: JB
authors: Robbins
authors: Rachel
authors: R
authors: Schneerson
authors: Rajesh K
authors: RK
authors: Gupta
authors: Zhigang
authors: Z
authors: Zhao
authors: Xiaomei
authors: X
authors: Tan
mesh_terms: D000907:Antibodies, Bacterial / Q000032:analysis / Q000276:immunology*; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology; D001428:Bacterial Vaccines / Q000276:immunology* / Q000592:standards*; D002675:Child, Preschool; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology*; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D011550:Pseudomonas aeruginosa / Q000276:immunology; D012015:Reference Standards; D012485:Salmonella typhi / Q000276:immunology*; D014435:Typhoid Fever / Q000276:immunology / Q000517:prevention & control; D018074:Vaccines, Conjugate / Q000276:immunology* / Q000592:standards*
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D007106:Immune Sera; D007074:Immunoglobulin G; D011135:Polysaccharides, Bacterial; D018074:Vaccines, Conjugate; C111749:pseudomonas exoprotein A protein, Pseudomonas aeruginosa