Immune activation alters cellular and humoral responses to yellow fever 17D vaccine

Abstract

Background. Defining the parameters that modulate vaccine responses in African populations will be imperative to design effective vaccines for protection against HIV, malaria, tuberculosis, and dengue virus infections. This study aimed to evaluate the contribution of the patient-specific immune microenvironment to the response to the licensed yellow fever vaccine 17D (YF-17D) in an African cohort. Conclusion.Together, these results demonstrate that an activated immune microenvironment prior to vaccination impedes efficacy of the YF-17D vaccine in an African cohort and suggest that vaccine regimens may need to be boosted in African populations to achieve efficient immunity.Trial registration. Registration is not required for observational studies.

Low Thymic Activity and Dendritic Cell Numbers Are Associated with the Immune Response to Primary Viral Infection in Elderly Humans

“…As previously shown, innate immunity induced by YF vaccination is generally important for the vaccine response outcome (18,42,43). In this article, we showed that we could classify vaccinees according to their age by multivariate analysis of major innate cell types.…”

“…Because induction of innate immunity by YF vaccination has been shown to critically influence elicitation of subsequent effector responses (18,42,43), we assessed absolute numbers of seven circulating innate cell types (Supplemental Fig. 1B) and evaluated them on the peak of innate immunity at day 4 by PCA.…”

Community deworming alleviates geohelminth-induced immune hyporesponsiveness

“…The effects could lead to enhanced immune responses to other pathogens and vaccines. With respect to vaccines, there is increasing concern regarding poor immunogenicity in rural areas of developing countries (28,29); therefore, any measure to alleviate hyporesponsiveness would have a major public health impact. It is also important to consider the long-standing evolutionary coexistence between humans and helminths, the disturbance of which might lead to the emergence of pathological conditions (30).…”

Antiviral Innate Immune Activation in HIV-Infected Adults Negatively Affects H1/IC31-Induced Vaccine-Specific Memory CD4+T Cells

“…Muyanja et al showed that the cellular and humoral immune responses to the highly efficacious live yellow fever vaccine YF-17D in East African individuals were substantially lower than those of European volunteers treated identically (30). Prior to vaccination, the East African volunteers presented an increased activated immune microenvironment with higher frequencies of exhausted and activated natural killer cells, differentiated B and T cells, and proinflammatory monocytes (30).…”