Production of IFN-γ by CD4⁺ T cells in the first week after 17DD and 17D/ SIV Gag recombinants immunization in mice.

<p>Percentages of CD4⁺ IFN- γ⁺ cells in draining lymph nodes and spleens of mice following 17 DD – (Lymph node-panel A; Spleen- panel D), 17D SIV Gag _45-269 (Lymph node-panel B; Spleen- panel E) and 17D Δ IRES (Lymph node- panel C, Spleen- panel F) immunization in C57BL/6 and BALB/c mice. Statistical analysis was performed by Two- Way ANOVA with Bonferroni post-test. * <i>p</i><0.05, ** <i>p</i><0.01, *** <i>p</i><0.001. The means are representative of three independent experiments. N= 3 animals/ experimental point.</p

Functional profile of CD4⁺ T cell responses in mice immunized with 17DD and 17D/ SIV Gag recombinants.

<p>ICCS for YF-specific and Gag-specific CD4⁺ T-cells at day 14 after immunization on secretion of IFN-γ and/or IL-2 following stimuli with antigen (whole inactivated YF 17DD virus -panels A, C and E and peptide mixtures spanning amino acids 1–291 of Gag -panels B, D and F). Bar graphs indicate the mean frequency of CD4⁺ splenocytes specific to YF and Gag capable of producing IFN-γ (black), IL-2 (white) or both (grey). Error bars represent the standard error of the mean. Differences between cytokine + cells were statistically significant between BALB/c and C57BL/6 mice (* p<0.05, **p<0.01). The means are representative of three independent experiments. N= 4 animals/ experiment.</p

Functional profile of CD8⁺ T cell responses in mice immunized with 17DD and 17D/ SIV Gag recombinants.

<p>ICCS for YF-specific and Gag-specific CD8⁺ T-cells at day 14 after immunization on secretion of IFN-γ and/or IL-2 following stimuli with antigen (whole inactivated YF 17DD virus -panels A, C and E and peptide mixtures spanning amino acids 1–291 of Gag -panels B, D and F). Bar graphs indicate the mean frequency of CD8⁺ splenocytes specific to YF and Gag capable of producing IFN-γ (black), IL-2 (white) or both (grey). Error bars represent the standard error of the mean. Differences between cytokine + cells were statistically significant between BALB/c and C57BL/6 mice (* p<0.05, **p<0.01). The means are representative of three independent experiments. N= 4 animals/ experiment.</p

Production of IFN-γ by γδ T cells in the first week after 17DD and 17D/ SIV Gag recombinants immunization in mice.

<p>Percentages of γδ⁺ T cells+ IFN- γ⁺ cells in draining lymph nodes and spleens of mice following 17 DD – (Lymph node-panel A; Spleen- panel D), 17D SIV Gag _45-269 (Lymph node-panel B; Spleen- panel E) and 17D Δ IRES (Lymph node- panel C, Spleen- panel F) immunization in C57BL/6 and BALB/c mice. Statistical analysis was performed by Two- Way ANOVA with Bonferroni post-test. * <i>p</i><0.05, ** <i>p</i><0.01, *** <i>p</i><0.001. The means are representative of three independent experiments. N= 3 animals/ experimental point.</p

Production of IFN-γ by CD8⁺ T cells in the first week after 17DD and 17D/ SIV Gag recombinants immunization in mice.

<p>Percentages of CD8⁺ IFN- γ⁺ cells in draining lymph nodes and spleens of mice following 17 DD – (Lymph node-panel A; Spleen- panel D), 17D SIV Gag _45-269 (Lymph node-panel B; Spleen- panel E) and 17D Δ IRES (Lymph node- panel C, Spleen- panel F) immunization in C57BL/6 and BALB/c mice. Statistical analysis was performed by Two- Way ANOVA with Bonferroni post-test. * <i>p</i><0.05, ** <i>p</i><0.01, *** <i>p</i><0.001. The means are representative of three independent experiments. N= 3 animals/ experimental point.</p

Humoral immune responses in animals vaccinated with YF 17DD and YF 17D recombinant viruses.

<p>Neutralizing antibodies levels, Total YF- IgG levels and IgG2a/ IgG1 ratios in mice sera following YF 17 DD (panels A - C), 17D SIV Gag _45-269 (panels D - F) and 17D Δ IRES (panels G - I) virus immunization in C57BL/6 and BALB/c mice. Statistical analysis was performed by Mann-Whitney T test. * <i>p</i><0.05, ** <i>p</i><0.01, *** <i>p</i><0.001. The medians are representative of three independent experiments.</p

Magnitude of YF and Gag-specific CD8⁺ T-cell responses in animals vaccinated with YF 17DD and YF 17D recombinant viruses.

<div><p>Groups of mice (C57BL/6 strain and BALB/c strain) were immunized twice 15 days apart with vehicle medium (mock), YF vaccine (17 DD), recombinant 17 D SIV-Gag _45-269 or recombinant 17 D Δ IRES virus. Spleen cells of each mouse were recovered 14 days after second immunization and cultured with 2 μg/mL of YF CD8 specific peptides (Panel A-C) or 5 mM of SIV Gag peptide pool (Panel D-F). Results are representative of three independent experiments and are normalized to non-stimulated cells control. Bars represent the medians. Statistics were done by Mann-Whitney T test. </p> <p>* <i>p</i><0.05, ** <i>p</i><0.01, *** <i>p</i><0.001.</p></div

Correlations between neutralizing antibodies and IgG2a levels in sera of mice immunized with YF 17DD and YF 17D recombinant viruses.

<p>Neutralizing antibodies levels and IgG2a O.Ds in mouse sera following YF 17 DD (panels A and B), YF 17D SIV Gag _45-269 (panels C and D) and YF 17D Δ IRES (panels E and F) virus immunization in C57BL/6 and BALB/c mice. The analysis was performed by Pearson’s correlation method.</p

ZIKV load in saliva of <i>Ae</i>. <i>aegypti</i> from Rio de Janeiro, Brazil, 14 and 21 days after challenge with two locally circulating ZIKV isolates (Rio-U1 and Rio-S1) provided at a titer of 10⁶ PFU/mL.

<p>Virus was detected plaque forming unit (PFU) assays on Vero cells. </p

Immunogenicity of Seven New Recombinant Yellow Fever Viruses 17D Expressing Fragments of SIVmac239 Gag, Nef, and Vif in Indian Rhesus Macaques

<div><p>An effective vaccine remains the best solution to stop the spread of human immunodeficiency virus (HIV). Cellular immune responses have been repeatedly associated with control of viral replication and thus may be an important element of the immune response that must be evoked by an efficacious vaccine. Recombinant viral vectors can induce potent T-cell responses. Although several viral vectors have been developed to deliver HIV genes, only a few have been advanced for clinical trials. The live-attenuated yellow fever vaccine virus 17D (YF17D) has many properties that make it an attractive vector for AIDS vaccine regimens. YF17D is well tolerated in humans and vaccination induces robust T-cell responses that persist for years. Additionally, methods to manipulate the YF17D genome have been established, enabling the generation of recombinant (r)YF17D vectors carrying genes from unrelated pathogens. Here, we report the generation of seven new rYF17D viruses expressing fragments of simian immunodeficiency virus (SIV)mac239 Gag, Nef, and Vif. Studies in Indian rhesus macaques demonstrated that these live-attenuated vectors replicated <em>in vivo,</em> but only elicited low levels of SIV-specific cellular responses. Boosting with recombinant Adenovirus type-5 (rAd5) vectors resulted in robust expansion of SIV-specific CD8⁺ T-cell responses, particularly those targeting Vif. Priming with rYF17D also increased the frequency of CD4⁺ cellular responses in rYF17D/rAd5-immunized macaques compared to animals that received rAd5 only. The effect of the rYF17D prime on the breadth of SIV-specific T-cell responses was limited and we also found evidence that some rYF17D vectors were more effective than others at priming SIV-specific T-cell responses. Together, our data suggest that YF17D – a clinically relevant vaccine vector – can be used to prime AIDS virus-specific T-cell responses in heterologous prime boost regimens. However, it will be important to optimize rYF17D-based vaccine regimens to ensure maximum delivery of all immunogens in a multivalent vaccine.</p> </div