Systems scale interactive exploration reveals quantitative and qualitative differences in response to influenza and pneumococcal vaccines.

Systems immunology approaches were employed to investigate innate and adaptive immune responses to influenza and pneumococcal vaccines. These two non-live vaccines show different magnitudes of transcriptional responses at different time points after vaccination. Software solutions were developed to explore correlates of vaccine efficacy measured as antibody titers at day 28. These enabled a further dissection of transcriptional responses. Thus, the innate response, measured within hours in the peripheral blood, was dominated by an interferon transcriptional signature after influenza vaccination and by an inflammation signature after pneumococcal vaccination. Day 7 plasmablast responses induced by both vaccines was more pronounced after pneumococcal vaccination. Together, these results suggest that comparing global immune responses elicited by different vaccines will be critical to our understanding of the immune mechanisms underpinning successful vaccination.

Human blood CXCR5(+)CD4(+) T cells are counterparts of T follicular cells and contain specific subsets that differentially support antibody secretion.

Although a fraction of human blood memory CD4(+) T cells expresses chemokine (C-X-C motif) receptor 5 (CXCR5), their relationship to T follicular helper (Tfh) cells is not well established. Here we show that human blood CXCR5(+)CD4(+) T cells share functional properties with Tfh cells and appear to represent their circulating memory compartment. Blood CXCR5(+)CD4(+) T cells comprised three subsets: T helper 1 (Th1), Th2, and Th17 cells. Th2 and Th17 cells within CXCR5(+), but not within CXCR5(-), compartment efficiently induced naive B cells to produce immunoglobulins via interleukin-21 (IL-21). In contrast, Th1 cells from both CXCR5(+) and CXCR5(-) compartments lacked the capacity to help B cells. Patients with juvenile dermatomyositis, a systemic autoimmune disease, displayed a profound skewing of blood CXCR5(+) Th cell subsets toward Th2 and Th17 cells. Importantly, the skewing of subsets correlated with disease activity and frequency of blood plasmablasts. Collectively, our study suggests that an altered balance of Tfh cell subsets contributes to human autoimmunity.

Development of a HIV-1 lipopeptide antigen pulsed therapeutic dendritic cell vaccine.

In the search for a therapeutic HIV-1 vaccine, we describe herein the development of a monocyte-derived dendritic cell (DC) vaccine loaded with a mixture of HIV-1-antigen lipopeptides (ANRS HIV-LIPO-5 Vaccine). LIPO-5 is comprised of five HIV-1-antigen peptides (Gag(17-35), Gag(253-284), Nef(66-97), Nef(116-145), and Pol(325-355)), each covalently linked to a palmitoyl-lysylamide moiety. Monocytes enriched from HIV-1-infected highly active antiretroviral therapy (HAART)-treated patients were cultured for three days with granulocyte-macrophage colony-stimulating factor and alpha-interferon. At day 2, the DCs were loaded with ANRS HIV-LIPO-5 vaccine, activated with lipopolysaccharide, harvested at day 3 and frozen. Flow cytometry analysis of thawed DC vaccines showed expression of DC differentiation markers: CD1b/c, CD14, HLA-DR, CD11c, co-stimulatory molecule CD80 and DC maturation marker CD83. DCs were capable of eliciting an HIV-1-antigen-specific response, as measured by expansion of autologous CD4(+) and CD8(+) T-cells. The expanded T-cells secreted gamma-IFN and interleukin (IL)-13, but not IL-10. The safety and immunogenicity of this DC vaccine are being evaluated in a Phase I/II clinical trial in chronically HIV-1-infected patients on HAART (clinicaltrials.gov identifier: NCT00796770).

Safety and immunogenicity of tyrosinase DNA vaccines in patients with melanoma.

Immunity to self antigens on cancer is constrained by tolerance/ignorance. DNA vaccines encoding xenogeneic differentiation antigens, such as tyrosinase (TYR), mediate tumor protection and regression in implantable mouse models, and dogs with spontaneous melanoma. We conducted a trial of mouse and human TYR DNA vaccines in stage III/IV melanoma patients. Eighteen human leukocyte antigen (HLA)-A*0201(+) melanoma patients were randomized as follows: one group received three mouse TYR DNA injections followed by three human TYR DNA injections; the other group received the same vaccines in opposite sequence. The study was conducted at three dose levels: 100, 500, and 1,500 microg DNA/injection, administered intramuscularly (IM) every 3 weeks. Most toxicities were grade 1 injection site reactions. Seven patients developed CD8(+) T-cell responses, defined by a >3 SD increase in baseline reactivity to TYR peptide in tetramer or intracellular cytokine staining (ICS) assays. There was found to be no relationship between dose, assigned schedule, and T-cell response. At a median of 42 months follow-up, median survival has not been reached. Mouse and human TYR DNA vaccines were found safe and induced CD8(+) T-cell responses in 7 of 18 patients. T cells recognizing a native TYR peptide had a phenotype consistent with that of effector memory cells.