title: A new 'total' activin B enzyme-linked immunosorbent assay (ELISA): development and validation for human samples.
abstract: OBJECTIVE
  There are currently no sensitive and specific assays for activin B that could be utilized to study human biological fluids. The aim of this project was to develop and validate a 'total' activin B ELISA for use with human biological fluids and establish concentrations of activin B in the circulation and fluids from the reproductive organs.
  
  
  METHODS
  The new ELISA was validated and then used to measure activin B levels in the circulation of healthy participants, IVF patients, pregnant women and in ovarian follicular fluid and seminal plasma.
  
  
  METHODS
  Healthy adult subjects (n = 143), subjects from an IVF clinic (n = 27) and pregnancy groups (n = 29) were sampled.
  
  
  RESULTS
  The sensitivity of the assay was 0.019 ng/ml. Validation of the activin B ELISA showed good recovery (90.7 +/- 9.8%) and linearity in biological fluid and cell culture media and low cross-reactivity with related analytes (inhibin B = 0.077% and activin A = 0.0034%). There was a negative correlation between activin B concentration (r = -0.281, P < 0.011) and females with increasing age. Patients attending IVF clinics had significantly lower levels of activin B compared with gender-matched control subjects. Ovarian follicular fluid and seminal plasma had 50-80 fold higher levels of activin B (mean = 5.35 and 3.66 ng/ml respectively) than sera (mean = 0.071 ng/ml).
  
  
  CONCLUSIONS
  This fully validated ELISA for activin B offers a tremendous utility for measuring this protein in a variety of normal physiological processes and in various clinical pathologies.
authors.affiliation: Centre for Proteins and Peptides, School of Life Sciences, Oxford Brookes University, Headington, Oxford, UK. helenludlow9@googlemail.com
authors.forename: Helen
authors.initials: H
authors.lastname: Ludlow
authors.forename: David J
authors.initials: DJ
authors.lastname: Phillips
authors.forename: Michelle
authors.initials: M
authors.lastname: Myers
authors.forename: Robert I
authors.initials: RI
authors.lastname: McLachlan
authors.forename: David M
authors.initials: DM
authors.lastname: de Kretser
authors.forename: Carolyn A
authors.initials: CA
authors.lastname: Allan
authors.forename: Richard A
authors.initials: RA
authors.lastname: Anderson
authors.forename: Nigel P
authors.initials: NP
authors.lastname: Groome
authors.forename: Marko
authors.initials: M
authors.lastname: Hyvönen
authors.forename: W Colin
authors.initials: WC
authors.lastname: Duncan
authors.forename: Shanthi
authors.initials: S
authors.lastname: Muttukrishna
mesh_terms: D028341:Activins / Q000032:analysis*; D000293:Adolescent; D000328:Adult; D000368:Aged; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015571:Follicular Fluid / Q000737:chemistry; D006801:Humans; D008297:Male; D008875:Middle Aged; D011247:Pregnancy; D012661:Semen / Q000737:chemistry; D055815:Young Adult
chemical_list: C044147:activin B; D028341:Activins