Post by Nadica (She/Her) on Aug 11, 2024 6:26:56 GMT
SARS-CoV-2 Omicron-B.1.1.529 leads to widespread escape from neutralizing antibody responses - Published Feb 3, 2022
In brief
A comprehensive analysis of sera from
vaccinees, convalescent patients
previously infected by multiple variants,
and potent monoclonal antibodies from
early in the COVID-19 pandemic reveals a
substantial overall reduction in the ability
to neutralize the SARS-CoV-2 Omicron
variant, which seems to ameliorate with a
third vaccine dose. Structural analyses of
the Omicron RBD suggest that selective
pressure balances key changes that
increase affinity for ACE2 with other
changes in the receptor-binding motif
that disfavor ACE2 binding but facilitate
immune escape
SUMMARY
On 24th November 2021, the sequence of a new SARS-CoV-2 viral isolate Omicron-B.1.1.529 was announced,
containing far more mutations in Spike (S) than previously reported variants. Neutralization titers of Omicron
by sera from vaccinees and convalescent subjects infected with early pandemic Alpha, Beta, Gamma, or
Delta are substantially reduced, or the sera failed to neutralize. Titers against Omicron are boosted by third
vaccine doses and are high in both vaccinated individuals and those infected by Delta. Mutations in Omicron
knock out or substantially reduce neutralization by most of the large panel of potent monoclonal antibodies
and antibodies under commercial development. Omicron S has structural changes from earlier viruses and
uses mutations that confer tight binding to ACE2 to unleash evolution driven by immune escape. This leads
to a large number of mutations in the ACE2 binding site and rebalances receptor affinity to that of earlier
pandemic viruses.
In brief
A comprehensive analysis of sera from
vaccinees, convalescent patients
previously infected by multiple variants,
and potent monoclonal antibodies from
early in the COVID-19 pandemic reveals a
substantial overall reduction in the ability
to neutralize the SARS-CoV-2 Omicron
variant, which seems to ameliorate with a
third vaccine dose. Structural analyses of
the Omicron RBD suggest that selective
pressure balances key changes that
increase affinity for ACE2 with other
changes in the receptor-binding motif
that disfavor ACE2 binding but facilitate
immune escape
SUMMARY
On 24th November 2021, the sequence of a new SARS-CoV-2 viral isolate Omicron-B.1.1.529 was announced,
containing far more mutations in Spike (S) than previously reported variants. Neutralization titers of Omicron
by sera from vaccinees and convalescent subjects infected with early pandemic Alpha, Beta, Gamma, or
Delta are substantially reduced, or the sera failed to neutralize. Titers against Omicron are boosted by third
vaccine doses and are high in both vaccinated individuals and those infected by Delta. Mutations in Omicron
knock out or substantially reduce neutralization by most of the large panel of potent monoclonal antibodies
and antibodies under commercial development. Omicron S has structural changes from earlier viruses and
uses mutations that confer tight binding to ACE2 to unleash evolution driven by immune escape. This leads
to a large number of mutations in the ACE2 binding site and rebalances receptor affinity to that of earlier
pandemic viruses.