VIOLIN Logo
VO Banner
Search: for Help
About
Introduction
Statistics
VIOLIN News
Your VIOLIN
Register or Login
Submission
Tutorial
Vaccine & Components
Vaxquery
Vaxgen
VBLAST
Protegen
VirmugenDB
DNAVaxDB
CanVaxKB
Vaxjo
Vaxvec
Vevax
Huvax
Cov19VaxKB
Host Responses
VaximmutorDB
VIGET
Vaxafe
Vaxar
Vaxism
Vaccine Literature
VO-SciMiner
Litesearch
Vaxmesh
Vaxlert
Vaccine Design
Vaxign2
Vaxign
Community Efforts
Vaccine Ontology
ICoVax 2012
ICoVax 2013
Advisory Committee
Vaccine Society
Vaxperts
VaxPub
VaxCom
VaxLaw
VaxMedia
VaxMeet
VaxFund
VaxCareer
Data Exchange
V-Utilities
VIOLINML
Help & Documents
Publications
Documents
FAQs
Links
Acknowledgements
Disclaimer
Contact Us
UM Logo

Vaccine Detail

M. tuberculosis secA2 mutant
Vaccine Information
  • Vaccine Name: M. tuberculosis secA2 mutant
  • Target Pathogen: Mycobacterium tuberculosis
  • Target Disease: Tuberculosis
  • Vaccine Ontology ID: VO_0000564
  • Type: Live, attenuated vaccine
  • SecA2 gene engineering:
    • Type: secA2 transformation into M. tuberculosis
    • Description: The secA2 gene was amplified by PCR from virulent H37Rv genomic DNA, cloned into a pGEM vector, and later excised as a fragment and cloned into pMV361 (Hinchey et al., 2007).
    • Detailed Gene Information: Click Here.
  • Preparation: Three virulent strains (M. tuberculosis H37Rv, HN878, and ΔsecA2 mutants) were obtained and grown on Middlebrook 7H9 broth or 7H10 agar containing 10% (vol/vol) oleic acid-albumin-dextrose-catalase, 0.5% glycerol, and 0.05% (vol/vol) Tween-80. Recombinant strains were selected using ampicillin, hygromycin, and kanamycin.
  • Description: The secA2 gene encodes a component of a virulence-associated bacterial protein secretion system and is required for prevention of apoptosis in macrophages infected with M. tuberculosis. The apoptotic response is related to secA2-dependent secretion of mycobacterial superoxide dismutase A (SodA). M. tuberculosis H37Rv with deleted secA2 induces apoptosis, as indicated by TUNEL and polycaspase activation in mouse and human macrophages (Hinchey et al., 2007). Extrinsic and intrinsic caspase pathways were linked to initiation of apoptosis in the secA2-deleted mutants via caspase 8 and 9 activity. The secretion of SodA appears to be important for the inhibition of apoptosis by secA2-dependent mechanisms. Furthermore,
Host Response

Mouse Response

  • Host Strain: B6.PL (Thy1.1+), SIINFEKL/H-2K^b-reactive TCR-transgenic OT-1
  • Vaccination Protocol: Donor splenocytes from Rag1 deficient OT1 TCR-transgenic mice were isolated and labeled with 20 μg CFSE and washed. Aliquots containing either 3x10^5 or 1x10^7 labeled cells were injected into lateral tail vein prior to subcutaneous or i.v. infection with 1x10^8 CFU M. tuberculosis ΔsecA2-OVA or control bacteria strains. Splenocytes were harvested and stained 5-7 days post-infection and analyzed by flow cytometry to determine percentage of undivided (high-CFSE) cells in the Thy1.2+ population (Hinchey et al., 2007).
  • Immune Response: OT-1 T cells infected with H37Rv, H37Rv-OVA, and ΔsecA2-OVA showed negligible, modest, and massive increases in proliferation of transferred T cells. SecA2 addition can restore OT-1 T cell priming activities in the mutants. Furthermore, SIINFEKL epitope is produced in all mutants in an immunogenic form. Additional evidence suggested that tight linkage exists among CD8+ T cell priming, loss of SodA secretion, and blocked apoptosis (Hinchey et al., 2007).
  • Challenge Protocol: No challenge was implemented here.
  • Description: Procedure was designed to visualize and better understand the priming of MHC class I restricted CD8+ T cells with SIINFEKL fusion protein, as well as understand the relationship between SodA secretion, apoptosis, and secA2 (Hinchey et al., 2007).
  • Information about this animal model: Mouse Model for TB research

Mouse Response

  • Host Strain: C57BL/6
  • Vaccination Protocol: Mice received 5x10^5 OT-1 cells one day before infecting subcutaneously with either 1x10^6 CFU H37Rv-OVA or ΔsecA2-OVA. Animals were sacrificed at 2, 4, or 20 weeks prior to splenic isolation and antibody labeling. Lympocyte subpopulations (CD44high,CD62high; CD44highCD62low) were quantified and separated using flow cytometry (Hinchey et al., 2007).
  • Immune Response: Infection with H37Rv, H37Rv-OVA or ΔRD1-OVA induced background levels of IFN-gamma spot-forming cells while the ΔsecA2-OVA infection induces a 10-fold increase of similar spots above the background levels. Additional evidence from an in vivo CTL assay for SIINFEKL -induced CD8+ T cell activity strengthened the claim that enhanced T cell priming in the sec2A deletion mutants is restricted to CD8+ T cell compartment (Hinchey et al., 2007).
  • Challenge Protocol: No challenge was introduced in this protocol.
  • Description: Purpose of this experiment was to analyze memory T cell populations and abundance within the native splenic environment, and to determine the extent of antigen transmission to dendritic cells and enhanced CD8+ T cell priming (Hinchey et al., 2007).
  • Information about this animal model: Mouse Model for TB research

Mouse Response

  • Host Strain: C57BL/6
  • Vaccination Protocol: Mice were vaccinated subcutaneously with 1x10^6 CFUs of either M. tuberculosis ΔsecA2 or M. bovis BCG-Pasteur.
  • Persistence: Substantial growth of HN878 observed in lungs and spleens within one month of challenge (Hinchey et al., 2007), whereas both M. tuberculosis ΔsecA2 or M. bovis BCG-Pasteur showed decreased loads at the same interval.
  • Immune Response: Mild inflammation including small/compact granulomas containing lymphocytes were observed for animals vaccinated with BCG or ΔsecA2 (Hinchey et al., 2007).
  • Challenge Protocol: Mice were challenged via aerosol route two months post-vaccination using GlasCol inhalation chamber. Approximately 50-100 CFUs of either M. tuberculosis Beijing/W (HN878) or Erdman strains were administered using this approach. Mice were sacrificed at 1, 3, and 5 months post-challenge prior to isolation of lung and spleen. Mice infected with the Erdman strain were observed daily until euthanization in a second survival study (Hinchey et al., 2007).
  • Efficacy: Protection by ΔsecA2 was significantly greater than in animals infected with M. bovis BCG-Pasteur at one month post-challenge (Hinchey et al., 2007). Furthermore, the protection offered by ΔsecA2 was still significant after five months post-challenge despite non-significant BCG protection at the same interval.
  • Information about this animal model: Mouse Model for TB research

Mouse Response

  • Host Strain: Outbred Hartley guinea pigs
  • Vaccination Protocol: Guinea pigs were vaccinated intradermally with 1x10^3 M. tuberculosis ΔsecA2 or BCG-Pasteur (Hinchey et al., 2007).
  • Persistence: Lower CFUs observed in ΔsecA2-immunized animals versus BCG and control animals (Hinchey et al., 2007).
  • Immune Response: Minor fibrosis observed for in ΔsecA2-immunized animals at 2 months post-challenge (Hinchey et al., 2007).
  • Challenge Protocol: Animals were challenged six weeks post-vaccination via aerosol route with 10-30CFUs of M. tuberculosis H37Rv strains (Madison chamber). Spleen, lung, and lymph node tissues were isolated at either 1 or 2 months post-challenge. (Hinchey et al., 2007).
  • Efficacy: The ΔsecA2-immunized animals exhibited significant decreases (p<.01) in lung, splenic, and mediastinal lymph node CFUs versus control animals. Notable differences in CFU counts and organ size in the mediastinal lymph nodes were observed in only the M. tuberculosis ΔsecA2-innoculated animals, including only minor fibrosis at two months post-challenge (Hinchey et al., 2007).
  • Description: Guinea pigs were vaccinated and challenged for CFU determination and histopathology comparison between different attenuated strains of M. tuberculosis and M. bovis. The results from the guinea pig study suggest that the . M. tuberculosis ΔsecA2 exceeds the efficacy of BCG in several aspects and may be a viable vaccine candidate (Hinchey et al., 2007).
  • Information about this animal model: Mouse Model for TB research
References
Hinchey et al., 2007: Hinchey J, Lee S, Jeon BY, Basaraba RJ, Venkataswamy MM, Chen B, Chan J, Braunstein M, Orme IM, Derrick SC, Morris SL, Jacobs WR, Porcelli SA. Enhanced priming of adaptive immunity by a proapoptotic mutant of Mycobacterium tuberculosis. The Journal of clinical investigation. 2007 Aug 1; 117(8); 2279-2288. [PubMed: 17671656].