Kriangkrai Chawansuntati. Neutralization and enhancement activities of monoclonal antibodies specific to the envelope protein of dengue viruses . Master's Degree(Immunology). Mahidol University. : Mahidol University, 2006.
Neutralization and enhancement activities of monoclonal antibodies specific to the envelope protein of dengue viruses
Abstract:
Envelope (E) protein is one of the most important antigens responsible for
dengue virus attachment and mediates virus-specific membrane fusion. Infection by
dengue virus induces anti-E neutralizing antibody production, one of the defensive
mechanisms to neutralize the virus. In the presence of non-neutralizing or subneutralizing
concentrations, anti-E antibodies are, in turn, involved in the antibodydependent
enhancement (ADE) of virus infection via Fc receptor bearing cells. In this
study, the in vitro neutralizing as well as enhancement activity of twelve anti-E
monoclonal antibodies (Mabs) to 4 prototype strains of each dengue serotype and
Japanese encephalitis virus Nakayama strain were determined. The dengue virussusceptible
cells, Ps clone D were used to determine the neutralizing activity of Mab,
while Fc receptor-bearing cells, U937 were used for ADE assay. The results indicated
that seven anti-E Mabs (4G2, 2B7, 1D10, 2C8, 8A1, 1H10, and J93) exhibited both
neutralizing and enhancement activity to each virus serotype correlating to their binding
properties. Two Mabs neutralized dengue virus infection, but enhanced none (for 3H5) or
some serotypes (for 1D3) of dengue virus infection. The other two Mabs neutralized only
dengue-2 virus infection, but enhanced both dengue-1 and 2 (for 1C2) or dengue-2 and 3
(for 5A1). One Mab (1F4), specific to dengue-2 virus, could not neutralize or enhance
dengue virus infection. It was also found that infection enhancement by 3H5 anti-E Mab
is dependent on the strain of virus, which is consistent with previous results. The
identified functional activities of anti-E Mabs would be additional information to identify
new epitopes contributing to dengue vaccine design