ABSTRACT Protein–energy malnutrition affects one in nine people worldwide and is most prevalent among children aged less than five years in low-income countries. Early childhood malnutrition can have damaging neurodevelopmental effects, with significant increases in cognitive, neurological and mental health problems over the lifespan, outcomes which can also extend to the next generation. This article describes a research collaboration involving scientists from five centers in Barbados, China, Cuba and the USA. It builds on longer-term joint work between the Barbados Nutrition Study (which, over a 45-year span, has extensively documented nutritional, health, behavioral, social and economic outcomes of individuals who experienced protein–energy malnutrition in the first year of life and healthy controls from the same classrooms and neighborhoods) and the Cuban Neuroscience Center (which has developed low-cost brain imaging methods that can be readily used in low income settings to identify biomarkers for early detection and treatment of adverse consequences of childhood malnutrition). This collaboration, which involved Barbadian, Cuban and US scientists began in the 1970s, when quantitative EEG techniques were applied to EEG data collected in 1977–78, at which time study participants were aged 5–11 years. These EEG records were never fully analyzed but were stored in New York and made available to this project in 2016. These data have now been processed and analyzed, comparing EEG findings in previously malnourished and control children, and have led to the identification of early biomarkers of long-term effects of early childhood protein–energy malnutrition. The next stage of the project will involve extending earlier work by collecting EEG recordings in the same individuals at ages 45–51 years, 40 years later, and comparing findings to earlier data and to these individuals’ behavioral and cognitive outcomes. Quantitative EEG biomarkers of the effects of protein–energy malnutrition may help identify children at greatest risk for early malnutrition’s adverse neurodevelopmental effects and inform development of targeted interventions to mitigate the long-term adverse effects of protein–energy malnutrition in developing countries.

A chimeric yellow fever (YF)-dengue serotype 2 (dengue 2) virus was constructed by replacing the premembrane and envelope genes of the YF 17D virus with those from dengue 2 virus strains of Southeast Asian genotype. The virus grew to high titers in Vero cells and, after passage 2, was used for immunogenicity and attenuation studies in rhesus monkeys. Subcutaneous immunization of naive rhesus monkeys with the 17D-D2 chimeric virus induced a neutralizing antibody response associated with the protection of 6 of 7 monkeys against viremia by wild-type dengue 2 virus. Neutralizing antibody titers to dengue 2 were significantly lower in YF-immune animals than in YF-naive monkeys and protection against challenge with wild-type dengue 2 virus was observed in only 2 of 11 YF-immune monkeys. An anamnestic response to dengue 2, indicated by a sharp increase of neutralizing antibody titers, was observed in the majority of the monkeys after challenge with wild-type virus. Virus attenuation was demonstrated using the standard monkey neurovirulence test. The 17D-D2 chimera caused significantly fewer histological lesions than the YF 17DD virus. The attenuated phenotype could also be inferred from the limited viremias compared to the YF 17DD vaccine. Overall, these results provide further support for the use of chimeric viruses for the development of a new live tetravalent dengue vaccine.

The yellow fever (YF) virus is the prototype flavivirus. The use of molecular techniques has unraveled the basic mechanisms of viral genome structure and expression. Recent trends in flavivirus research include the use of infectious clone technology with which it is possible to recover virus from cloned cDNA. Using this technique, mutations can be introduced at any point of the viral genome and their resulting effect on virus phenotype can be assessed. This approach has opened new possibilities to study several biological viral features with special emphasis on the issue of virulence/attenuation of the YF virus. The feasibility of using YF virus 17D vaccine strain, for which infectious cDNA is available, as a vector for the expression of heterologous antigens is reviewed

The Oswaldo Cruz Foundation produces most of the yellow fever (YF) vaccine prepared world wide. As part of a broader approach to determine the genetic variability in YF l7D seeds and vaccines and its relevance to viral attenuation the 17DD virus was purifed directly from chick embryo homogenates which is the source of virus used for vaccination of millions of people in Brazil and other countries for half a century. Neutralization and hemagglutination tests showed that the purified virus is similar to the original stock. Furthermore, radioimmune precipitation of 35S-methionine-labeled viral proteins using mouse hyperimmune ascitic fluid revealed identical patterns for the purified 17DD virus and the YF l7D-204 strain except for the 17DD E protein which migrated slower on SDS-PAGE. This difference is likely to be due to N-linked glycosylation. Finally, comparison by northern blot nybridization of virion RNAs of purified 17DD with two other strains of YF virus only fenome-sized molecules for all three viruses. These observations suggest that vaccine phenotype is primarily associated with the accumulation of mutations.