Subversion of early innate antiviral responses during antibody-dependent enhancement of Dengue virus infection induces severe disease in immunocompetent mice Julia T. de Castro

UNIVERSIDADE FEDERAL DE MINAS GERAIS IMMUNOFARMACOLOGY GROUP MOST OF THEM UNIVERSIDADE FEDERAL DE MINAS GERAIS IMMUNOFARMACOLOGY GROUP Where is… I STUDY AND WORK!

Summary Introduction to Dengue Antibody-Dependent Enhancement (ADE) Methods Results Conclusion Paper discussion

Dengue Fever Tropical and subtropical disease Transmitted by the bite of the female mosquito Aedes aegypti Female mosquitoes generally lay their eggs above the water inside containers as tires, buckets, birdbaths, water storage jars, and flower pots. dengue.org.br nature.com saude.hsw.uol.com.br

Dengue Map Absent Improbable Probable Present

Dengue virus DENV is a RNA virus Four well-known serotypes (DENV1, DENV2, DENV3 and DENV4) A fifth type was discovered in 2013

Immune Response Infection of Langerhans cells Innate immunity Secretion of IFN Infected cells go to lymph nodes Adaptive immunity Abs, complement, Cytotoxic T lymphocytes

Dengue fever

Severe Dengue healthxchange.com.sg

How severe disease is developed? Few hypotheses Antibody-Dependent Enhancement (ADE)

Antibody-Dependent Enhancement (ADE) nature.com Antibodies from the first infection are cross-reactive with other DENV serotypes But Abs are subneutralizing FcγR recognizes Abs and internalizes immunocomplex Evidences suggest that the mechanism is associated with both increase in the number of infected cells, a phenomenon called “Extrinsic ADE,” and a subversion of the intracellular innate immune host responses through suppression of a the type I IFN and proinflammatory cytokines production—an event denominated as “Intrinsic ADE”

Let’s go to the paper… Methods ELISA PCR Immunohistochemistry Plaque Assay Plaque reduction neutralization test in Vero Cells (PRNT) virology.ws

Results B cells are necessary for host resistance to primary Dengue infection *B-cell-deficient mice (μMT−/−) Fig. 1

Conclusions B cells are protective to primary infection

Fig. 2 Preexisting immunity can exacerbate disease? *Mice injected with anti-DENV3 serum and infected with DENV-2 Fig. 2

Conclusions B cells are protective to primary infection B-cell activation and antibody production can exert a dual role

To test whether the levels of Ab would directly impact on severe disease *Commercial anti-DENV clone 4G2 (15 μg and 400 μg) at day −1, day +1 and day +3 Fig. 3

Conclusions B cells are protective to primary infection B-cell activation and antibody production can exert a dual role Presence of non-neutralizing or subneutralizing levels of Ab can worsen disease (ADE)

ADE-mediated severe disease resembles primary disease with high inoculum *4G2 treated mice, sub lethal inoculum (100 PFU) and lethal (1000 PFU) Fig. 4

Parameters of disease in day 7 (peak) Fig. 5

Conclusions B cells are protective to primary infection B-cell activation and antibody production can exert a dual role Presence of non-neutralizing or subneutralizing levels of Ab can worsen disease (ADE) subneutralizing levels of anti-DENV antibodies enhance viral replication to similar extents found in mice primarily infected with a higher DENV inoculum

Fig. 6 Involvement of FcγRs *Mice treated with an FcγR-blocking Ab in the presence or not of 4G2 Fig. 6

Conclusions B cells are protective to primary infection B-cell activation and antibody production can exert a dual role Presence of non-neutralizing or subneutralizing levels of Ab can worsen disease (ADE) subneutralizing levels of anti-DENV antibodies enhance viral replication to similar extents found in mice primarily infected with a higher DENV inoculum FcγRs play an essential role in disease

Intrinsic ADE Mice A129 -/- have more severe disease (supplementary figures) Fig. 7

Conclusions B cells are protective to primary infection B-cell activation and antibody production can exert a dual role Presence of non-neutralizing or subneutralizing levels of Ab can worsen disease (ADE) subneutralizing levels of anti-DENV antibodies enhance viral replication to similar extents found in mice primarily infected with a higher DENV inoculum FcγRs play an essential role in disease Type I IFN play an essential role during primary and secondary infections

Passive intravenous immunoglobulin therapy (IVIG) containing subneutralizing titers of Ab Fig. 8

Conclusions B cells are protective to primary infection B-cell activation and antibody production can exert a dual role Presence of non-neutralizing or subneutralizing levels of Ab can worsen disease (ADE) subneutralizing levels of anti-DENV antibodies enhance viral replication to similar extents found in mice primarily infected with a higher DENV inoculum FcγRs play an essential role in disease Type I IFN play an essential role during primary and secondary infections

Conclusions Vaccines Treatments