Low Levels of Antibody-Dependent Enhancement in Vitro Using Viruses and Plasma from Dengue Patients

Abstract

BackgroundThe majority of dengue patients infected with any serotype of dengue virus (DENV) are asymptomatic, but the remainder may develop a wide spectrum of clinical symptoms, ranging from mild dengue fever (DF) to severe dengue hemorrhagic fever (DHF). Severe cases occur more often in patients who experience a secondary infection with a different virus serotype. A phenomenon called antibody-dependent enhancement (ADE) has been proposed to explain the onset of these severe cases, but the exact mechanism of ADE remains unclear.Methodology/Principal FindingVirus neutralization and ADE assays were performed using ultracentrifugation supernatants of acute-phase sera from patients with secondary infections or human monoclonal antibodies (HuMAbs) as anti-DENV antibodies. Virus sources included infectious serum-derived viruses from the ultracentrifugation precipitates, laboratory-culture adapted DENV, or recombinant DENVs derived from patient sera. In contrast to the high levels of ADE observed with laboratory virus strains, low ADE was observed with autologous patient-derived viruses, when patient sera were used to provide the antibody component in the ADE assays. Similar results were obtained using samples from DF and DHF patients. Recombinant-viruses derived from DHF patients showed only minor differences in neutralization and ADE activity in the presence of HuMAbs or plasma derived from the same DHF patient.Conclusion/SignificanceSerum or plasma taken from patients during the acute phase of a secondary infection showed high levels of ADE, but no neutralization activity, when assayed in the presence of laboratory-adapted virus strains. By contrast, serum or plasma from the same patient showed high levels of neutralization activity but failed to induce significant ADE when the assays were performed with autologous virus. These results demonstrate the significance of the virus source when measuring ADE. They also suggest that repeated passage of DENV in cell culture has endowed it with the capacity to induce high levels of ADE.

Evidence of plasticity in the dengue virus: Host cell interaction

“…A similar result was found with K562 cells, a second cell line capable of ADE infection. Recently Chaichana and colleagues showed that viruses isolated directly from patient serum were unable to undergo ADE of infection [28], similar to the inability of our low passage isolates to undergo ADE infection.…”

“…2). Similar results showing low ADE infection with DENVs purified directly from patient sera have recently been published [28].…”

Dengue virus infection of erythroid precursor cells is modulated by both thalassemia trait status and virus adaptation

“…As with previous studies (Chaichana et al, 2014;Diamond et al, 2000) we found markedly different consequences when infection was undertaken with high and low passage viruses. We found undetectable levels of infection of cells when low passage DENVs were used as the infecting virus.…”

“…As several studies have shown that laboratory adapted DENVs can show behavior distinct from that of low passage DENV isolates (Chaichana et al, 2014;Diamond et al, 2000;Edgil et al, 2003), normal control day 7 erythroid committed precursor cells were mock infected or infected with DENV-2 high passage (16681) as used in the previous experiments and a low passage DENV-2 isolate 5, 9, 13), Hb E trait (lanes 2, 6, 10, 14), β-thalassemia trait (lanes 3, 7, 11, 15) and α-thalassemia-1 trait (lanes 4, 8, 12, 16) were either infected (DENV) or mock infected (Mock) on day 7 and day 10 and analyzed after 48 h by western blotting for expression of DENV NS1 and GAPDH in a duplex analysis. (B) Supernatants were collected from day 7 erythroid precursor cells of three normal controls (N1, N2 and N3) at 48 after mock or DENV-2 infection.…”

Dengue NS1 antigen contributes to disease severity by inducing interleukin (IL)-10 by monocytes

“…NS1‐specific antibodies are believed to contribute to disease pathogenesis by activating complement and also leading to endothelial dysfunction . Therefore, in order to investigate if DENV‐NS1‐specific antibodies could potentiate the effects of NS1, we used DENV immune sera in ADE experiments as described previously . We found that there was a trend towards DENV immune sera potentiating the effects of NS1 on monocytes and the production of IL‐10 was higher, especially at 48 h (Fig.…”