ABSTRACT
Haptoglobins (HPs) are alpha 2-globulin proteins that bind free hemoglobin in plasma to prevent oxidative damage. HPs are produced as preproteins that are proteolytically cleaved in the ER into alpha and beta chains prior to forming mature, functional tetramers. Two alleles exist in humans (HP1 and HP2), therefore three genotypes are present in the population, i.e., HP1-1, HP2-1, and HP2-2. A biochemical role for nascent haptoglobin 2 (pre-haptoglobin 2 or pre-HP2) as the only known modulator of intestinal permeability has been established. In addition, elevated levels of serum pre-HP2 have been detected in multiple conditions including celiac disease and type I diabetes, which are believed to result in part through dysregulation of the intestinal barrier. In this study, we report the development of a monoclonal antibody that is specific for pre-HP2 with a binding affinity in the nanomolar range. Additional antibodies with specificities for preHP but not mature haptoglobin were also characterized. A sandwich enzyme-linked immunosorbent assay (ELISA) was established and validated. The ELISA showed high specificity for pre-HP2 even in the presence of excess pre-HP1 or mature haptoglobins, and has excellent linearity and inter- and intra-assay reproducibility with a working range from 3.1ng/mL to 200ng/mL. Testing of sera from 76 healthy patients revealed a non-Gaussian distribution of pre-HP2 levels with a mean concentration of 221.2ng/mL (95% CI: 106.5-335.9ng/mL) and a median value of 23.9ng/mL. Compared to current approaches, this ELISA offers a validated, monoclonal-based method with high sensitivity and specificity for measuring pre-HP2 in human serum.
Subject(s)
Antibodies, Monoclonal/immunology , Haptoglobins/analysis , Haptoglobins/immunology , Amino Acid Sequence , Animals , Enzyme-Linked Immunosorbent Assay , Epitope Mapping , Humans , Mice , Molecular Sequence DataABSTRACT
An outbreak of measles due to secondary vaccine failure prompted this investigation into the prevalence of measles antibody in children. We studied 608 children in 7 different age groups: 6, 9, 14 and 18 months and 6, 10 and 15 years. Children in the 2 youngest groups received no vaccination; the rest were vaccinated at 9 months and 15 months. The 15-year-old age group received an additional vaccination. Transplacental measles antibody (Ab) decreased from 10.0% at 6 months to 0% at 9 months. Measles Ab was positive in 52.9% (14 months), 89.4% (18 months), 60.8% 96 years), 45.0% (10 years) and 96.8% (15 years). To increase Ab levels, a booster vaccination is recommended, administered either with the second DPT booster or at pre-high school age.
Subject(s)
Antibodies, Viral/blood , Disease Outbreaks/statistics & numerical data , Immunoglobulin G/blood , Measles virus/immunology , Measles/epidemiology , Measles/prevention & control , Adolescent , Age Distribution , Child , Child, Preschool , Disease Outbreaks/prevention & control , Enzyme-Linked Immunosorbent Assay , Female , Humans , Immunization, Secondary , Incidence , Infant , Infectious Disease Transmission, Vertical/statistics & numerical data , Iran/epidemiology , Male , Measles/blood , Measles/immunology , Measles/transmission , Needs Assessment , Population Surveillance , Prevalence , Seroepidemiologic Studies , Socioeconomic Factors , Urban Health/statistics & numerical data , VaccinationABSTRACT
An outbreak of measles due to secondary vaccine failure prompted this investigation into the prevalence of measles antibody in children. We studied 608 children in 7 different age groups: 6, 9, 14 and 18 months and 6, 10 and 15 years. Children in the 2 youngest groups received no vaccination; the rest were vaccinated at 9 months and 15 months. The 15-year-old age group received an additional vaccination. Transplacental measles antibody [Ab] decreased from 10.0% at 6 months to 0% at 9 months. Measles Ab was positive in 52.9% [14 months], 89.4% [18 months], 60.8% 96 years], 45.0% [10 years] and 96.8% [15 years].To increase Ab levels, a booster vaccination is recommended, administered either with the second DPT booster or at pre-high school age
