title: The influence of haemoglobin and iron on in vitro mycobacterial growth inhibition assays.
abstract: The current vaccine against tuberculosis, live attenuated Mycobacterium bovis BCG, has variable efficacy, but development of an effective alternative is severely hampered by the lack of an immune correlate of protection. There has been a recent resurgence of interest in functional in vitro mycobacterial growth inhibition assays (MGIAs), which provide a measure of a range of different immune mechanisms and their interactions. We identified a positive correlation between mean corpuscular haemoglobin and in vitro growth of BCG in whole blood from healthy UK human volunteers. Mycobacterial growth in peripheral blood mononuclear cells (PBMC) from both humans and macaques was increased following the experimental addition of haemoglobin (Hb) or ferric iron, and reduced following addition of the iron chelator deferoxamine (DFO). Expression of Hb genes correlated positively with mycobacterial growth in whole blood from UK/Asian adults and, to a lesser extent, in PBMC from South African infants. Taken together our data indicate an association between Hb/iron levels and BCG growth in vitro, which may in part explain differences in findings between whole blood and PBMC MGIAs and should be considered when using such assays.
authors.affiliation: The Jenner Institute, University of Oxford, Oxford, UK.
authors.forename: Rachel
authors.initials: R
authors.lastname: Tanner
authors.affiliation: The Jenner Institute, University of Oxford, Oxford, UK.
authors.forename: Matthew K
authors.initials: MK
authors.lastname: O'Shea
authors.affiliation: Public Health England, Porton Down, Salisbury, UK.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: White
authors.affiliation: The Jenner Institute, University of Oxford, Oxford, UK.
authors.forename: Julius
authors.initials: J
authors.lastname: Müller
authors.affiliation: The Jenner Institute, University of Oxford, Oxford, UK.
authors.forename: Rachel
authors.initials: R
authors.lastname: Harrington-Kandt
authors.affiliation: The Jenner Institute, University of Oxford, Oxford, UK.
authors.forename: Magali
authors.initials: M
authors.lastname: Matsumiya
authors.affiliation: Public Health England, Porton Down, Salisbury, UK.
authors.forename: Mike J
authors.initials: MJ
authors.lastname: Dennis
authors.affiliation: The Jenner Institute, University of Oxford, Oxford, UK.
authors.forename: Eneida A
authors.initials: EA
authors.lastname: Parizotto
authors.affiliation: The Jenner Institute, University of Oxford, Oxford, UK.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Harris
authors.affiliation: The Jenner Institute, University of Oxford, Oxford, UK.
authors.forename: Elena
authors.initials: E
authors.lastname: Stylianou
authors.affiliation: The Jenner Institute, University of Oxford, Oxford, UK.
authors.forename: Vivek
authors.initials: V
authors.lastname: Naranbhai
authors.affiliation: The Jenner Institute, University of Oxford, Oxford, UK.
authors.forename: Paulo
authors.initials: P
authors.lastname: Bettencourt
authors.affiliation: Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK.
authors.forename: Hal
authors.initials: H
authors.lastname: Drakesmith
authors.affiliation: Public Health England, Porton Down, Salisbury, UK.
authors.forename: Sally
authors.initials: S
authors.lastname: Sharpe
authors.affiliation: London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Helen A
authors.initials: HA
authors.lastname: Fletcher
authors.affiliation: The Jenner Institute, University of Oxford, Oxford, UK.
authors.forename: Helen
authors.initials: H
authors.lastname: McShane
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D001500:BCG Vaccine / Q000008:administration & dosage; D003676:Deferoxamine / Q000494:pharmacology*; D004909:Erythrocyte Indices; D015870:Gene Expression; D006454:Hemoglobins / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology*; D006801:Humans; D007223:Infant; D007501:Iron / Q000494:pharmacology*; D007502:Iron Chelating Agents / Q000494:pharmacology*; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000276:immunology / Q000382:microbiology; D008213:Lymphocyte Activation; D008253:Macaca mulatta; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009163:Mycobacterium bovis / Q000187:drug effects* / Q000254:growth & development / Q000276:immunology; D009169:Mycobacterium tuberculosis / Q000254:growth & development / Q000276:immunology; D061251:Primary Cell Culture; D014611:Vaccination
chemical_list: D001500:BCG Vaccine; D006454:Hemoglobins; D007502:Iron Chelating Agents; D007501:Iron; D003676:Deferoxamine