Individuals with less severe disease following secondary DENV2 illness maintained constant levels of antibody avidity over time

Individuals with less severe disease following secondary DENV2 illness maintained constant levels of antibody avidity over time. 18 months post-illness using a urea enzyme-linked immunosorbent assay. == Results == The data show a significant increase in avidity from acute to convalescent phase followed by a decrease from convalescent phase to 3 months post-symptom onset, then a plateau. Linear regression analysis comparing antibody avidity between disease severity groups over time indicate that individuals with more severe disease (DHF/DSS) experienced higher decay in antibody avidity over time compared to less severe disease (DF), and ROC curve analysis showed Isoacteoside that at 18 months post-illness, lower avidity was associated with previously having experienced more severe disease. == Conclusions == These data suggest that improved dengue disease severity is definitely associated with lower antibody avidity at later on time-points post-illness. Keywords:Dengue disease, antibody avidity, dengue hemorrhagic fever/dengue shock syndrome, disease severity == Background == The four dengue disease serotypes (DENV1-4) are responsible for probably the most common mosquito-borne viral illness in humans, with up to 96 million symptomatic dengue instances yearly and 3.6 billion people at risk for infection in tropical and subtropical regions worldwide (1). DENV causes a spectrum of disease ranging from self-limiting dengue fever (DF) to the severe, life-threatening dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) (2). People exposed to main DENV infections develop long-term serotype-specific neutralizing antibody reactions, whereas secondary DENV infections generally result in neutralizing serotype cross-reactive reactions (3). Although the majority of secondary DENV infections having a heterotypic serotype result in subclincal or less severe disease (DF), secondary infection is definitely a risk element for more severe disease (DHF/DSS) (3). In Nicaragua, the epidemiology of dengue is generally characterized by waves of one dominant serotype followed by another (4,5). DENV infections in Nicaragua in 2006-2007 were mainly DENV2 and designated by heightened medical severity (5). DENV2 has been reported to result in more severe disease than illness with additional serotypes (3,6-9). In addition, a change in the circulating DENV2 clade, together with the hosts serotype-specific immunity, contributed to improved disease severity upon DENV2 illness during this period in Nicaragua (5). Here, we examined the anti-DENV2 serum IgG avidity in samples collected in 2006-2007 as part of a pediatric hospital-based study in Managua, Nicaragua. In this study, suspected dengue instances are enrolled at demonstration, treated and analyzed during the acute phase of illness, and adopted longitudinally Isoacteoside for 18 months, with healthy blood samples collected at 14-21 days (convalescent), 3, 6, and 18 months post-illness (10). The mechanism(s) underlying the potential for improved disease severity in secondary DENV infection are not fully recognized but are thought to involve both serotype cross-reactive T Rabbit Polyclonal to Bcl-6 cell reactions and cross-reactive, poorly-neutralizing antibodies that can participate in antibody-dependent enhancement (ADE), whereby the Fc portion of non-neutralizing antibodies complexes with infecting virions to facilitate disease access into Fc receptor-bearing target cells (3,11-14). However, antibodies and T cells also contribute to safety Isoacteoside in secondary infections (3). The effectiveness of the antibody response is definitely modulated by both the affinity and avidity of the antibody/antigen connection, where avidity is the overall strength of antibody binding to its antigen and is affected by antibody affinity, antibody valency, epitope convenience, and epitope denseness (15). What part antibody avidity contributes to safety or pathogenesis during DENV illness offers yet to be elucidated. A previous study from our laboratory reported an association between anti-DENV3 serum IgG avidity and neutralization during DENV3 secondary infections (16). Utilizing the same revised urea avidity enzyme-linked immunosorbent assay (ELISA), we assessed the association between disease severity and antibody avidity. == Objectives == The focus of this study was to evaluate anti-DENV2 IgG avidity over time after secondary illness and to examine the association of avidity with disease severity. == Study Design == == Ethics statement == The protocol for this study was examined and authorized by the Institutional Review Boards of the University or college of California, Berkeley, and the Nicaraguan Ministry of Health. Parents or legal guardians of all subjects provided written educated consent, and subjects.