Cytokine signatures of innate and adaptive immunity in 17DD yellow fever vaccinated children and its association with the level of neutralizing antibody.

BACKGROUND: The live attenuated yellow fever (YF) vaccines have been available for decades and are considered highly effective and one of the safest vaccines worldwide. METHODS: The impact of YF-17DD-antigens recall on cytokine profiles of YF-17DD-vaccinated children were characterized using short-term cultures of whole blood samples and single-cell flow cytometry. This study enrolled seroconverters and nonseroconverters after primovaccination (PV-PRNT⁺ and PV-PRNT⁻), seroconverters after revaccination (RV-PRNT⁺), and unvaccinated volunteers (UV-PRNT⁻). RESULTS: The analysis demonstrated in the PV-PRNT⁺ group a balanced involvement of pro-inflammatory/regulatory adaptive immunity with a prominent participation of innate immunity pro-inflammatory events (IL-12⁺ and TNF-α⁺ NEU and MON). Using the PV-PRNT⁺ cytokine signature as a reference profile, PV-PRNT⁻ presented a striking lack of innate immunity proinflammatory response along with an increased adaptive regulatory profile (IL-4⁺CD4⁺ T cells and IL-10⁺ and IL-5⁺CD8⁺ T cells). Conversely, the RV-PRNT⁺ shifted the overall cytokine signatures toward an innate immunity pro-inflammatory profile and restored the adaptive regulatory response. CONCLUSIONS: The data demonstrated that the overall cytokine signature was associated with the levels of PRNT antibodies with a balanced innate/adaptive immunity with proinflammatory/regulatory profile as the hallmark of PV-PRNT(MEDIUM⁺), whereas a polarized regulatory response was observed in PV-PRNT⁻ and a prominent proinflammatory signature was the characteristic of PV-PRNT(HIGH⁺).

Variation rhythms of lymphocyte subsets during healthy aging.

Immunological alterations associated with aging (immunosenescence) do not represent a simple unidirectional decline in all functions but develop as a complex remodeling of the immune system, involving multiple reorganization and developmentally regulated changes. In general, most data available about aging were obtained at particular age intervals and most of them come from Caucasian individuals from either Europe or the United States. Here, we report the frequencies of major lymphocyte subsets in healthy Brazilian individuals from 2 distinct geographic regions (Southeast and South) at several age intervals spanning a lifetime period (0-86 years). Overall, we demonstrated that changes in the frequencies of cells related to both innate and adaptive immunity clearly occur with aging in these individuals. These changes were not progressive and equally steady for all cell populations tested but instead showed an oscillatory or rhythmic behavior that was distinctive of each population at different age intervals. We also observed that abrupt changes in the frequencies of immune cells may occur in healthy individuals over 75 years old, suggesting there is an impaired flexibility of the immune system at late stages of life to sustain homeostasis via immune mechanisms. We presented reference ranges for healthy Brazilian individuals at all ages. The knowledge of these parameters in further detail will allow interventions to optimize immune function in advanced age and to improve the quality of life in the elderly.

Distinct patterns of cellular immune response elicited by influenza non-adjuvanted and AS03-adjuvanted monovalent H1N1(pdm09) vaccine.

The study aimed at identifying biomarkers of immune response elicited by non-adjuvanted-(NAV) and adjuvanted-(AV) H1N1(pdm09) vaccines. The results showed that despite both vaccines elicited similar levels of anti-H1N1 antibodies at day30 after vaccination, higher reactivity was observed in AV at day180. While AV induced early changes in cell-surface molecules on monocytes, CD4+, CD8+ T-cells and B-cells, NAV triggered minor changes, starting later on at day3. Furthermore, AV induced a late and persistent increase in TLR gene expression after day3, except for tlr4, while NAV displayed earlier but transient tlr3/4/7/9 up-regulation. Contrasting with NAV, prominent chemokine gene expression (cxcl8,cxcl9,ccl5) and a broad spectrum up-regulation of plasmatic biomarkers (CXCL8,IL-6,IL-1ß,IL-12,IL-10) was evident in AV, which showed a major involvement of TNF and IL-10. Similarly, AV induced a robust IL-10-modulated proinflammatory storm, with early and persistent involvement of TNF-α/IL-12/IFN-γ axis derived from NK-cells, CD4+ and CD8+ T-cells along with promiscuous production of IL-4/IL-5/IL-13. Conversely, NAV promotes a concise and restricted intracytoplasmic chemokine/cytokine response, essentially mediated by TNF-α and IL-4, with late IL-10 production by CD8+ T-cells. Systems biology approach underscored that AV guided the formation of an imbricate network characterized by a progressive increase in the number of neighborhood connections amongst innate and adaptive immunity. In AV, the early cross-talk between innate and adaptive immunity, followed by the triad NK/CD4+/CD8+ T-cells at day3, sponsored a later/robust biomarker network. These findings indicate the relevance of adjuvanted vaccination to orchestrate broad, balanced and multifactorial cellular immune events that lead ultimately to a stronger H1N1 humoral immunity.

17DD and 17D-213/77 yellow fever substrains trigger a balanced cytokine profile in primary vaccinated children.

BACKGROUND: This study aimed to compare the cytokine-mediated immune response in children submitted to primary vaccination with the YF-17D-213/77 or YF-17DD yellow fever (YF) substrains. METHODS: A non-probabilistic sample of eighty healthy primary vaccinated (PV) children was selected on the basis of their previously known humoral immune response to the YF vaccines. The selected children were categorized according to their YF-neutralizing antibody titers (PRNT) and referred to as seroconverters (PV-PRNT(+)) or nonseroconverters (PV-PRNT(-)). Following revaccination with the YF-17DD, the PV-PRNT(-) children (YF-17D-213/77 and YF-17DD groups) seroconverted and were referred as RV-PRNT(+). The cytokine-mediated immune response was investigated after short-term in vitro cultures of whole blood samples. The results are expressed as frequency of high cytokine producers, taking the global median of the cytokine index (YF-Ag/control) as the cut-off. RESULTS: The YF-17D-213/77 and the YF-17DD substrains triggered a balanced overall inflammatory/regulatory cytokine pattern in PV-PRNT(+), with a slight predominance of IL-12 in YF-17DD vaccinees and a modest prevalence of IL-10 in YF-17D-213/77. Prominent frequency of neutrophil-derived TNF-α and neutrophils and monocyte-producing IL-12 were the major features of PV-PRNT(+) in the YF-17DD, whereas relevant inflammatory response, mediated by IL-12(+)CD8(+) T cells, was the hallmark of the YF-17D-213/77 vaccinees. Both substrains were able to elicit particular but relevant inflammatory events, regardless of the anti-YF PRNT antibody levels. PV-PRNT(-) children belonging to the YF-17DD arm presented gaps in the inflammatory cytokine signature, especially in terms of the innate immunity, whereas in the YF-17D-213/77 arm the most relevant gap was the deficiency of IL-12-producing CD8(+)T cells. Revaccination with YF-17DD prompted a balanced cytokine profile in YF-17DD nonresponders and a robust inflammatory profile in YF-17D-213/77 nonresponders. CONCLUSION: Our findings demonstrated that, just like the YF-17DD reference vaccine, the YF-17D-213/77 seed lot induced a mixed pattern of inflammatory and regulatory cytokines, supporting its universal use for immunization.

Characterization of main cytokine sources from the innate and adaptive immune responses following primary 17DD yellow fever vaccination in adults.

The mechanisms of immune response following yellow fever (YF-17DD) vaccination are still poorly understood. In this study, we have performed a longitudinal investigation (days 0, 7, 15 and 30) to characterize the cytokine profile of innate and adaptive immunity following YF-17DD first-time vaccination. Data from non-stimulated cultures demonstrated a prominent participation of the innate immunity with increased frequency of TNF-α(+) neutrophils and IFN-γ(+) NK-cells at day 7 besides TNF-α(+) monocytes at day 7, day 15 and day 30. Increased frequency of IL-10(+) monocytes was observed at day 15 and day 30, and decreased percentage of IL-4(+) NK-cells were detected at day 7, day 15 and day 30. Time-dependent and oscillating cytokine pattern was observed in CD4(+) T-cells, with low percentage of IL-12(+), IL-4(+) and IL-10(+) cells at day 7 and increased frequency of TNF-α(+) cells at day 15 besides IFN-γ(+) and IL-5(+) cells at day 15 and day 30. Later changes with increased percentage of IL-12(+) and IL-5(+)CD8(+) T-cells were observed at day 30. Increased frequency of IL-10(+) B-cells was observed at day 15, when seroconversion was detected in all vaccinees. The overall cytokine analysis of non-stimulated leukocytes showed a transient shift towards a pro-inflammatory profile at day 7, mainly due to changes in the innate immunity, which draws back toward a mixed/regulatory pattern at day 15 and day 30. The changes induced by the in vitro YF-17DD vaccine-stimulation were mainly observed at day 0 and day 7 (before seroconversion) with minor changes at day 15 and day 30 (after seroconversion). These data support the hypothesis that a complex network with mixed pro/anti-inflammatory cytokine profile is associated with the establishment of the protective immunity following YF-17DD primo-vaccination, free of adverse events.

Clinical and immunological insights on severe, adverse neurotropic and viscerotropic disease following 17D yellow fever vaccination.

Yellow fever (YF) vaccines (17D-204 and 17DD) are well tolerated and cause very low rates of severe adverse events (YEL-SAE), such as serious allergic reactions, neurotropic adverse diseases (YEL-AND), and viscerotropic diseases (YEL-AVD). Viral and host factors have been postulated to explain the basis of YEL-SAE. However, the mechanisms underlying the occurrence of YEL-SAE remain unknown. The present report provides a detailed immunological analysis of a 23-year-old female patient. The patient developed a suspected case of severe YEL-AVD with encephalitis, as well as with pancreatitis and myositis, following receipt of a 17D-204 YF vaccination. The patient exhibited a decreased level of expression of Fc-gammaR in monocytes (CD16, CD32, and CD64), along with increased levels of NK T cells (an increased CD3(+) CD16(+/-) CD56(+/-)/CD3(+) ratio), activated T cells (CD4(+) and CD8(+) cells), and B lymphocytes. Enhanced levels of plasmatic cytokines (interleukin-6 [IL-6], IL-17, IL-4, IL-5, and IL-10) as well as an exacerbated ex vivo intracytoplasmic cytokine pattern, mainly observed within NK cells (gamma interferon positive [IFN-gamma(+)], tumor necrosis factor alpha positive [TNF-alpha(+)], and IL-4 positive [IL-4(+)]), CD8(+) T cells (IL-4(+) and IL-5(+)), and B lymphocytes (TNF-alpha(+), IL-4(+), and IL-10(+)). The analysis of CD4(+) T cells revealed a complex profile that consisted of an increased frequency of IL-12(+) and IFN-gamma(+) cells and a decreased percentage of TNF-alpha(+), IL-4(+), and IL-5(+) cells. Depressed cytokine synthesis was observed in monocytes (TNF-alpha(+)) following the provision of antigenic stimuli in vitro. These results support the hypothesis that a strong adaptive response and abnormalities in the innate immune system may be involved in the establishment of YEL-AND and YEL-AVD.

Innate immunity phenotypic features point toward simultaneous raise of activation and modulation events following 17DD live attenuated yellow fever first-time vaccination.

Detailed multiparametric phenotypic investigation aiming to characterize the kinetics of the innate immune response in the peripheral blood following 17DD yellow fever (17DD-YF) first-time vaccination was performed. Results showed increased frequency of monocytes and NK cell subpopulations besides unexpected up-regulation of granulocytes activation status (CD28+/CD23+ and CD28+/HLA-DR+, respectively). Up-regulation of Fcgamma-R and IL-10-R expression emerge as putative events underlying the mixed pattern of phenotypic features triggered by the 17DD yellow fever (17DD-YF) vaccination. Mixed pattern of chemokine receptors expression further support our hypothesis that a parallel establishment of activation/modulation microenvironment plays a pivotal role in the protective immunity triggered by the 17DD-YF vaccine.