Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 Jan 29;12(1):e0006240.
doi: 10.1371/journal.pntd.0006240. eCollection 2018 Jan.

Trypanosoma cruzi vaccine candidate antigens Tc24 and TSA-1 recall memory immune response associated with HLA-A and -B supertypes in Chagasic chronic patients from Mexico

Liliana E Villanueva-Lizama  1 , Julio V Cruz-Chan  1   2 , Amarú Del C Aguilar-Cetina  1 , Luis F Herrera-Sanchez  3 , Jose M Rodriguez-Perez  4 , Miguel E Rosado-Vallado  1 , Maria J Ramirez-Sierra  1 , Jaime Ortega-Lopez  5 , Kathryn Jones  2 , Peter Hotez  2   6   7 , Maria Elena Bottazzi  2   7 , Eric Dumonteil  1   8
Affiliations

Trypanosoma cruzi vaccine candidate antigens Tc24 and TSA-1 recall memory immune response associated with HLA-A and -B supertypes in Chagasic chronic patients from Mexico

Liliana E Villanueva-Lizama et al. PLoS Negl Trop Dis. .

Abstract

Trypanosoma cruzi antigens TSA-1 and Tc24 have shown promise as vaccine candidates in animal studies. We evaluated here the recall immune response these antigens induce in Chagasic patients, as a first step to test their immunogenicity in humans. We evaluated the in vitro cellular immune response after stimulation with recombinant TSA-1 (rTSA-1) or recombinant Tc24 (rTc24) in mononuclear cells of asymptomatic Chagasic chronic patients (n = 20) compared to healthy volunteers (n = 19) from Yucatan, Mexico. Proliferation assays, intracellular cytokine staining, cytometric bead arrays, and memory T cell immunophenotyping were performed by flow cytometry. Peripheral blood mononuclear cells (PBMC) from Chagasic patients showed significant proliferation after stimulation with rTc24 and presented a phenotype of T effector memory cells (CD45RA-CCR7-). These cells also produced IFN-γ and, to a lesser extent IL10, after stimulation with rTSA-1 and rTc24 proteins. Overall, both antigens recalled a broad immune response in some Chagasic patients, confirming that their immune system had been primed against these antigens during natural infection. Analysis of HLA-A and HLA-B allele diversity by PCR-sequencing indicated that HLA-A03 and HLA-B07 were the most frequent supertypes in this Mexican population. Also, there was a significant difference in the frequency of HLA-A01 and HLA-A02 supertypes between Chagasic patients and controls, while the other alleles were evenly distributed. Some aspects of the immune response, such as antigen-induced IFN-γ production by CD4+ and CD8+ T cells and CD8+ proliferation, showed significant association with specific HLA-A supertypes, depending on the antigen considered. In conclusion, our results confirm the ability of both TSA-1 and Tc24 recombinant proteins to recall an immune response induced by the native antigens during natural infection in at least some patients. Our data support the further development of these antigens as therapeutic vaccine against Chagas disease.

PubMed Disclaimer

Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. ELISA to detect antigen specific antibodies.
Total IgG anti-Tc24 (A) and anti-TSA-1 (B) antibodies in seronegative controls and Chagasic chronic patients. Horizontal black lines indicate the mean optical density (O.D.) per group. *Indicates significant differences between seronegative and Chagasic patients (P <0.05, t test). Numbers in parenthesis indicate the sample size for each group.
Fig 2
Fig 2. Antigen-specific proliferation assay.
Stimulation index of CD3+, CD3+CD4+ and CD3+CD8+ T cells populations from seronegative controls (open circles) and Chagasic patients (Black circles), after stimulation with rTc24 (A) or rTSA-1 (B). Horizontal black lines indicate the mean. The dotted horizontal line shows the cut-off value to identify responders/non-responders. *Indicate significant differences in the proportion of responders between seronegative and Chagasic patients (P <0.05, Fisher test). Numbers in parenthesis indicate the sample size for each group.
Fig 3
Fig 3. Phenotyping of CD4+ T memory cells.
PBMC cells from seronegative controls (open circles) and Chagasic patients (black circles) were stimulated with rTc24, and phenotyped as T effector memory (TEM), T central memory (TCM) or T naïve (TNAIVE) cells. Horizontal black lines indicate the mean of the group. *Indicates significant differences between seronegative and Chagasic patients (P <0.05, t test for parametric distribution or U Mann-Whitney for non-parametric distribution). Numbers in parenthesis indicate the sample size for each group.
Fig 4
Fig 4. Antigen-specific cytokines produced by CD4+ and CD8+ T cells.
Stimulation index of CD4+ (A, B) and CD8+ (C, D) T cells expressing INF-γ or IL-10 in a group of T. cruzi seronegative controls (open circles) and Chagasic patients (black circles). Horizontal lines indicate the mean. *Indicate significant differences between seronegative and Chagasic patients (P<0.05, U Mann-Withney). Numbers in parenthesis indicate the sample size for each group.
Fig 5
Fig 5. Quantification of Th1 and Th2 soluble cytokines.
Th1 and Th2 cytokines were measured in supernatant of cultures after stimulation with TSA-1 (A) or Tc24 (B). Graphs show the concentration in pg/mL comparing seronegative control and Chagasic patients for each cytokine. N.D.: Not detected. Results include 13 Chagasic patients and 7 seronegative controls.
Fig 6
Fig 6. Antigen-specific immune network.
Networks were constructed using Cytoscape to provide an integrated view of Tc24 and TSA-1 recall responses in Chagasic patients and seronegative controls. Circle nodes represent T cell populations and cytokines, with the black circle corresponding to seronegative controls, and the colored circles corresponding to the seropositive Chagasic patients. A larger size of the circle indicates activation, while a smaller size indicates an inhibition/reduction compared to the seronegative controls. Pink colors are associated with a pro-inflammatory Th1 profile, while green is associated with an anti-inflammatory immune profile. Blue reflects non-polarized immune responses. Edges link nodes showing differences between Chagasic patients and controls.
Fig 7
Fig 7. HLA restriction of antigen-specific immune response.
The antigen-specific immune responses were analyzed according to the HLA supertypes of the study participants. Data are presented as mean ± SEM for the induction of CD8+ T cell proliferation (A), CD8+-IFN- γ ratio (B), and CD4+ IFN-γ ratio (C). *Indicates a significant difference in the antigen-specific immune response between HLA supertypes.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Rassi A Jr., Rassi A, Marin-Neto JA (2010) Chagas disease. Lancet 375: 1388–1402. doi: 10.1016/S0140-6736(10)60061-X - DOI - PubMed
    1. Perez-Molina JA, Molina I (2017) Chagas disease. Lancet. - PubMed
    1. Gunter SM, Murray KO, Gorchakov R, Beddard R, Rossmann SN, et al. (2017) Likely Autochthonous Transmission of Trypanosoma cruzi to Humans, South Central Texas, USA. Emerg Infect Dis 23: 500–503. doi: 10.3201/eid2303.161157 - DOI - PMC - PubMed
    1. Beaumier CM, Gillespie PM, Strych U, Hayward T, Hotez PJ, et al. (2016) Status of vaccine research and development of vaccines for Chagas disease. Vaccine 34: 2996–3000. doi: 10.1016/j.vaccine.2016.03.074 - DOI - PubMed
    1. Antinori S, Galimberti L, Bianco R, Grande R, Galli M, et al. (2017) Chagas disease in Europe: A review for the internist in the globalized world. Eur J Intern Med. - PubMed

Publication types

MeSH terms

Grants and funding

This work was supported by the Consejo Nacional de Ciencia y Tecnología (www.conacyt.gob.mx) grant #CB-2010-01-156513 (ED) and scholarship #319117 (LEVL) and by the Carlos Slim Foundation (www.fundacioncarlosslim.org) grant #187714 (ED, MEB, PH). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.