Lack of immune responses to Mycobacterium tuberculosis DosR regulon proteins following Mycobacterium bovis BCG vaccination.
Mycobacterium bovis BCG is widely used as a vaccine against tuberculosis (TB), despite its variable protective efficacy. Relatively little is known about the immune response profiles following BCG vaccination in relation to protection against TB. Here we tested whether BCG vaccination results in immune responses to DosR (Rv3133c) regulon-encoded proteins. These so-called TB latency antigens are targeted by the immune system during persistent Mycobacterium tuberculosis infection and have been associated with immunity against latent M. tuberculosis infection. In silico analysis of the DosR regulon in BCG and M. tuberculosis showed at least 97% amino acid sequence homology, with 41 out of 48 genes being identical. Transcriptional profiling of 14 different BCG strains, under hypoxia and nitric oxide exposure in vitro, revealed a functional DosR regulon similar to that observed in M. tuberculosis. Next, we assessed human immune responses to a series of immunodominant TB latency antigens and found that BCG vaccination fails to induce significant responses to latency antigens. Similar results were obtained with BCG-vaccinated BALB/c mice. In contrast, responses to latency antigens were observed in individuals with suspected exposure to TB (as indicated by positive gamma interferon responses to TB-specific antigens ESAT-6 and CFP-10) and in mice vaccinated with plasmid DNA encoding selected latency antigens. Since immune responses to TB latency antigens have been associated with control of latent M. tuberculosis infection, our findings support the development of vaccination strategies incorporating DosR regulon antigens to complement and improve the current BCG vaccine.
Lin
May Young
MY
Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, 2300 RC Leiden, The Netherlands.
Geluk
Annemieke
A
Smith
Steven G
SG
Stewart
Amanda L
AL
Friggen
Annemieke H
AH
Franken
Kees L M C
KL
Verduyn
Marleen J C
MJ
van Meijgaarden
Krista E
KE
Voskuil
Martin I
MI
Dockrell
Hazel M
HM
Huygen
Kris
K
Ottenhoff
Tom H M
TH
Klein
Michèl R
MR
D000293:Adolescent; D000328:Adult; D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D001500:BCG Vaccine / Q000008:administration & dosage* / Q000276:immunology; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D002417:Cattle; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis*; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D018085:Regulon / Q000235:genetics / Q000276:immunology*; D014376:Tuberculosis / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D014611:Vaccination
D000942:Antigens, Bacterial; D001500:BCG Vaccine; D001426:Bacterial Proteins; C118127:HspX protein, Mycobacterium tuberculosis; D007371:Interferon-gamma