Limits...
A DNA vaccine encoding multiple HIV CD4 epitopes elicits vigorous polyfunctional, long-lived CD4+ and CD8+ T cell responses.

Rosa DS, Ribeiro SP, Almeida RR, Mairena EC, Postól E, Kalil J, Cunha-Neto E - PLoS ONE (2011)

Bottom Line: Moreover, polyfunctional and long-lived specific memory T cells have been associated to vaccine-induced protection.The vaccine also generated long-lived central and effector memory CD4(+) T cells, a desirable feature for T-cell based vaccines.By virtue of inducing broad, polyfunctional and long-lived T cell responses against conserved CD4(+) T cell epitopes, combined administration of this vaccine concept may provide sustained help for CD8(+) T cells and antibody responses- elicited by other HIV immunogens.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Clinical Immunology and Allergy-LIM60, Division of Clinical Immunology and Allergy, Department of Medicine, University of São Paulo School of Medicine, São Paulo, Brazil.

ABSTRACT
T-cell based vaccines against HIV have the goal of limiting both transmission and disease progression by inducing broad and functionally relevant T cell responses. Moreover, polyfunctional and long-lived specific memory T cells have been associated to vaccine-induced protection. CD4(+) T cells are important for the generation and maintenance of functional CD8(+) cytotoxic T cells. We have recently developed a DNA vaccine encoding 18 conserved multiple HLA-DR-binding HIV-1 CD4 epitopes (HIVBr18), capable of eliciting broad CD4(+) T cell responses in multiple HLA class II transgenic mice. Here, we evaluated the breadth and functional profile of HIVBr18-induced immune responses in BALB/c mice. Immunized mice displayed high-magnitude, broad CD4(+)/CD8(+) T cell responses, and 8/18 vaccine-encoded peptides were recognized. In addition, HIVBr18 immunization was able to induce polyfunctional CD4(+) and CD8(+) T cells that proliferate and produce any two cytokines (IFNγ/TNFα, IFNγ/IL-2 or TNFα/IL-2) simultaneously in response to HIV-1 peptides. For CD4(+) T cells exclusively, we also detected cells that proliferate and produce all three tested cytokines simultaneously (IFNγ/TNFα/IL-2). The vaccine also generated long-lived central and effector memory CD4(+) T cells, a desirable feature for T-cell based vaccines. By virtue of inducing broad, polyfunctional and long-lived T cell responses against conserved CD4(+) T cell epitopes, combined administration of this vaccine concept may provide sustained help for CD8(+) T cells and antibody responses- elicited by other HIV immunogens.

Show MeSH

Related in: MedlinePlus

Immunization with HIVBr18 induces IFNγ and IL-2 secretion and proliferation against multiple HIV-1 epitopes.Two weeks after the last immunization with HIVBr18 or the empty pVAX1 vector, pooled spleen cells from 6 BALB/c mice were cultured in the presence of HIV-1 peptides (5 µM) or medium only. (A) Frequencies of HIV peptide-specific IFNγ (left pie chart) and IL-2 (right pie chart) secreting cells were measured by ELISPOT assay. The responses are shown by displaying each the number of SFU/106 cells for each positive peptide as a proportion of the sum of SFU/106 cells for all positive peptides. (B) Proliferative T cell responses were assessed by CFSE dilution assay. Splenocytes were labeled with CFSE (1.25 µM) and cultured for 5 days. After staining with fluorochrome-labeled anti-CD3, -CD4 and -CD8 monoclonal antibodies, cells were analyzed by flow cytometry. CFSE dilution on gated CD3+CD4+ or CD3+CD8+ cells was used as a readout for antigen-specific proliferation. Representative dot plots of CD4+ (upper panels) and CD8+ (lower panels) T cell proliferation (values in boxes represent % CFSElow cells) of splenocytes from HIVBr18 immunized mice; Data are representative of nine independent immunization experiments.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3037933&req=5

pone-0016921-g001: Immunization with HIVBr18 induces IFNγ and IL-2 secretion and proliferation against multiple HIV-1 epitopes.Two weeks after the last immunization with HIVBr18 or the empty pVAX1 vector, pooled spleen cells from 6 BALB/c mice were cultured in the presence of HIV-1 peptides (5 µM) or medium only. (A) Frequencies of HIV peptide-specific IFNγ (left pie chart) and IL-2 (right pie chart) secreting cells were measured by ELISPOT assay. The responses are shown by displaying each the number of SFU/106 cells for each positive peptide as a proportion of the sum of SFU/106 cells for all positive peptides. (B) Proliferative T cell responses were assessed by CFSE dilution assay. Splenocytes were labeled with CFSE (1.25 µM) and cultured for 5 days. After staining with fluorochrome-labeled anti-CD3, -CD4 and -CD8 monoclonal antibodies, cells were analyzed by flow cytometry. CFSE dilution on gated CD3+CD4+ or CD3+CD8+ cells was used as a readout for antigen-specific proliferation. Representative dot plots of CD4+ (upper panels) and CD8+ (lower panels) T cell proliferation (values in boxes represent % CFSElow cells) of splenocytes from HIVBr18 immunized mice; Data are representative of nine independent immunization experiments.

Mentions: To analyze whether immunization with HIVBr18 could induce specific T cell immune responses, BALB/c mice were immunized with HIVBr18 or the empty vector pVAX1. Fifteen days after the last dose, splenocytes from immunized mice were incubated with each of the 18 HIV-1 peptides encoded by the DNA vaccine, and specific IFNγ and IL-2 secretion was measured by ELISPOT assay. We detected IFNγ and IL-2 secreting cells against eight (Figure 1A) HIVBr18- encoded peptides; all peptides that induced IFNγ secretion were also capable to elicit IL-2 secretion. The recognized peptides p17 (73–89), p6 (32–46), pol (785–799), gp160 (188–201), rev (11027), vpr (58–65), vif (144–158) and nef (180–194) consistently presented positive responses over multiple independent immunization experiments. In contrast, T cells from pVAX1 immunized mice presented negligible numbers of IFNγ and IL-2 secreting cells after incubation with HIVBr18 peptides, in all performed experiments.


A DNA vaccine encoding multiple HIV CD4 epitopes elicits vigorous polyfunctional, long-lived CD4+ and CD8+ T cell responses.

Rosa DS, Ribeiro SP, Almeida RR, Mairena EC, Postól E, Kalil J, Cunha-Neto E - PLoS ONE (2011)

Immunization with HIVBr18 induces IFNγ and IL-2 secretion and proliferation against multiple HIV-1 epitopes.Two weeks after the last immunization with HIVBr18 or the empty pVAX1 vector, pooled spleen cells from 6 BALB/c mice were cultured in the presence of HIV-1 peptides (5 µM) or medium only. (A) Frequencies of HIV peptide-specific IFNγ (left pie chart) and IL-2 (right pie chart) secreting cells were measured by ELISPOT assay. The responses are shown by displaying each the number of SFU/106 cells for each positive peptide as a proportion of the sum of SFU/106 cells for all positive peptides. (B) Proliferative T cell responses were assessed by CFSE dilution assay. Splenocytes were labeled with CFSE (1.25 µM) and cultured for 5 days. After staining with fluorochrome-labeled anti-CD3, -CD4 and -CD8 monoclonal antibodies, cells were analyzed by flow cytometry. CFSE dilution on gated CD3+CD4+ or CD3+CD8+ cells was used as a readout for antigen-specific proliferation. Representative dot plots of CD4+ (upper panels) and CD8+ (lower panels) T cell proliferation (values in boxes represent % CFSElow cells) of splenocytes from HIVBr18 immunized mice; Data are representative of nine independent immunization experiments.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3037933&req=5

pone-0016921-g001: Immunization with HIVBr18 induces IFNγ and IL-2 secretion and proliferation against multiple HIV-1 epitopes.Two weeks after the last immunization with HIVBr18 or the empty pVAX1 vector, pooled spleen cells from 6 BALB/c mice were cultured in the presence of HIV-1 peptides (5 µM) or medium only. (A) Frequencies of HIV peptide-specific IFNγ (left pie chart) and IL-2 (right pie chart) secreting cells were measured by ELISPOT assay. The responses are shown by displaying each the number of SFU/106 cells for each positive peptide as a proportion of the sum of SFU/106 cells for all positive peptides. (B) Proliferative T cell responses were assessed by CFSE dilution assay. Splenocytes were labeled with CFSE (1.25 µM) and cultured for 5 days. After staining with fluorochrome-labeled anti-CD3, -CD4 and -CD8 monoclonal antibodies, cells were analyzed by flow cytometry. CFSE dilution on gated CD3+CD4+ or CD3+CD8+ cells was used as a readout for antigen-specific proliferation. Representative dot plots of CD4+ (upper panels) and CD8+ (lower panels) T cell proliferation (values in boxes represent % CFSElow cells) of splenocytes from HIVBr18 immunized mice; Data are representative of nine independent immunization experiments.
Mentions: To analyze whether immunization with HIVBr18 could induce specific T cell immune responses, BALB/c mice were immunized with HIVBr18 or the empty vector pVAX1. Fifteen days after the last dose, splenocytes from immunized mice were incubated with each of the 18 HIV-1 peptides encoded by the DNA vaccine, and specific IFNγ and IL-2 secretion was measured by ELISPOT assay. We detected IFNγ and IL-2 secreting cells against eight (Figure 1A) HIVBr18- encoded peptides; all peptides that induced IFNγ secretion were also capable to elicit IL-2 secretion. The recognized peptides p17 (73–89), p6 (32–46), pol (785–799), gp160 (188–201), rev (11027), vpr (58–65), vif (144–158) and nef (180–194) consistently presented positive responses over multiple independent immunization experiments. In contrast, T cells from pVAX1 immunized mice presented negligible numbers of IFNγ and IL-2 secreting cells after incubation with HIVBr18 peptides, in all performed experiments.

Bottom Line: Moreover, polyfunctional and long-lived specific memory T cells have been associated to vaccine-induced protection.The vaccine also generated long-lived central and effector memory CD4(+) T cells, a desirable feature for T-cell based vaccines.By virtue of inducing broad, polyfunctional and long-lived T cell responses against conserved CD4(+) T cell epitopes, combined administration of this vaccine concept may provide sustained help for CD8(+) T cells and antibody responses- elicited by other HIV immunogens.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Clinical Immunology and Allergy-LIM60, Division of Clinical Immunology and Allergy, Department of Medicine, University of São Paulo School of Medicine, São Paulo, Brazil.

ABSTRACT
T-cell based vaccines against HIV have the goal of limiting both transmission and disease progression by inducing broad and functionally relevant T cell responses. Moreover, polyfunctional and long-lived specific memory T cells have been associated to vaccine-induced protection. CD4(+) T cells are important for the generation and maintenance of functional CD8(+) cytotoxic T cells. We have recently developed a DNA vaccine encoding 18 conserved multiple HLA-DR-binding HIV-1 CD4 epitopes (HIVBr18), capable of eliciting broad CD4(+) T cell responses in multiple HLA class II transgenic mice. Here, we evaluated the breadth and functional profile of HIVBr18-induced immune responses in BALB/c mice. Immunized mice displayed high-magnitude, broad CD4(+)/CD8(+) T cell responses, and 8/18 vaccine-encoded peptides were recognized. In addition, HIVBr18 immunization was able to induce polyfunctional CD4(+) and CD8(+) T cells that proliferate and produce any two cytokines (IFNγ/TNFα, IFNγ/IL-2 or TNFα/IL-2) simultaneously in response to HIV-1 peptides. For CD4(+) T cells exclusively, we also detected cells that proliferate and produce all three tested cytokines simultaneously (IFNγ/TNFα/IL-2). The vaccine also generated long-lived central and effector memory CD4(+) T cells, a desirable feature for T-cell based vaccines. By virtue of inducing broad, polyfunctional and long-lived T cell responses against conserved CD4(+) T cell epitopes, combined administration of this vaccine concept may provide sustained help for CD8(+) T cells and antibody responses- elicited by other HIV immunogens.

Show MeSH
Related in: MedlinePlus