SARS-CoV-2 Y453F and L452R variants contribute to evasion from cellular
immunity and the L452R variant also increases viral infectivity.
From: Motozono, C. et.al., Cell Host & Microbe, 2021.(CC BY 4.0)
SARS-CoV-2 spike mutation L452R evades human immune response and enhances
infectivity | News | Kumamoto University
Creationist mode:
Creationism's malevolent designer, having gone to such lengths, catalogued in
this blog, to design the SARS-CoV-2 virus to kill as many people as possible and
make many more sick, was never going to take defeat by human medical science
with its clever vaccines, lightly.
Now scientists from Kumamoto University, Japan, have shown how it has redesigned
the virus' spike protein so it not only makes it more infective but also helps
it evade the immunity produced in response to the vaccines, which specifically
target the spike protein.
This mutation, or as Creationists would call it, the new design, is known to
science as L452R and is already present in both the δ-variant and the
ε-variant. The δ-variant is the one currently responsible for the
massive increase in infections in much of the world, include the UK, where new
cases have rocketed from under 1,700 daily new cases in early May to over 54,000
four days ago, although we have seen a slight falling back from that figure to
44,000 new cases today. Most experts are predicting a large increase over the
next few weeks, possibly reaching 100,000 new cases next month. Unless some of
the restrictions, including obligatory wearing of face coverings in enclosed
public spaces and public transport are reimposed, I think this figure is easily
achievable.
UK Daily New Covid-19 infections (21 Jul, 2021)
Immunity in response to the vaccines has two components:
-
Humoral immunity (antibodies circulating in the blood which attack the viral
spike proteins rendering them innactive).
-
Cellular immunity (pre-programmed helper and killer T-cells, produced in the
bone marrow on demand when cells signal that they have been infected).
The new 'design' appears to lessen the effect of the humoral immunity because
the modification in the spike protein means they don't bind so firmly to the
virus. It makes the virus more infective because it binds more firmly to the
ACE2 proteins on the cell surface, so gains entry to the cell more quickly, and
it reduces the mobilisation of T-cells, especially in people who carry the
HLA-A24 allel, which is common in East and South-Asian people.
So, it seems the intelligent [sic] designer has left no stone unturned in its
search for its next move in the arms race with human medical science.
Creationist mode:
Now the real science:
The L452R mutation is a hallmark of the Delta variant that is currently
spreading worldwide, and in Japan, about 60% of the population have HLA-A24,
which is responsible for cellular immunity. The L452R mutation not only
evades the HLA-A24 cellular immunity but can also enhance the infectivity of
the virus. We have been carefully investigating the immune response against
emerging SARS-CoV-2 variants in real time to monitor how the mutations
affect human immunity and viral infectivity.
Dr. Chihiro Motozono, Senior author
Division of Infection and Immunity,
Joint Research Center for Human Retrovirus Infection,
Kumamoto University, Kumamoto, Japan
The Y453F and L452R mutations were located in the receptor binding domain of
the SARS-CoV-2 spike protein, which are crucial for gaining entry into host
cells. Researchers thus examined the effects of these mutations on the
infection and replication efficiency of the virus. They found that the L452R
mutation enhances its membrane fusion activity, infectivity, and viral
replication.
The team's findings were published recently, open access, in the journal, Cell
Host & Microbe:
Highlights
- L452R and Y453F mutations in the SARS-CoV-2 spike RBM have emerged
- L452R and Y453F mutants escape HLA-A24-restricted cellular immunity
-
L452R increases viral infectivity and fusogenicity and promotes viral
replication
Summary
Many SARS-CoV-2 variants with naturally acquired mutations have emerged. These
mutations can affect viral properties such as infectivity and immune
resistance. Although the sensitivity of naturally occurring SARS-CoV-2
variants to humoral immunity has been investigated, sensitivity to human
leukocyte antigen (HLA)-restricted cellular immunity remains largely
unexplored. Here, we demonstrate that two recently emerging mutations in the
receptor-binding domain of the SARS-CoV-2 spike protein, L452R (in B.1.427/429
and B.1.617) and Y453F (in B.1.1.298), confer escape from HLA-A24-restricted
cellular immunity. These mutations reinforce affinity toward the host entry
receptor ACE2. Notably, the L452R mutation increases spike stability, viral
infectivity, viral fusogenicity, and thereby promotes viral replication. These
data suggest that HLA-restricted cellular immunity potentially affects the
evolution of viral phenotypes and that a further threat of the SARS-CoV-2
pandemic is escape from cellular immunity.
Motozono, Chihiro; Toyoda, Mako; Zahradnik, Jiri; Saito, Akatsuki; Nasser,
Hesham; Tan, Toong Seng; Ngare, Isaac; Kimura, Izumi; Uriu, Keiya; Kosugi,
Yusuke; Yue, Yuan; Shimizu, Ryo; Ito, Jumpei; Torii, Shiho; Yonekawa, Akiko;
Shimono, Nobuyuki; Nagasaki, Yoji; Minami, Rumi; Toya, Takashi; Sekiya,
Noritaka; Fukuhara, Takasuke; Matsuura, Yoshiharu; Schreiber, Gideon; Ikeda,
Terumasa; Nakagawa, So; Ueno, Takamasa; Sato, Kei
SARS-CoV-2 spike L452R variant evades cellular immunity and increases
infectivity
Cell Host & Microbe, Volume 29, Issue 7, 1124 - 1136.e11
Copyright: © 2021 The authors. Published by Elsevier Inc.
Open access.
Reprinted under a
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0
International License (CC BY-NC-ND 4.0)
The reason this is happening with the SARS-CoV-2 virus is obvious to anyone who
has even a rudimentary understanding of evolution. Occasional variations in the
replication of the viral RNA in infected cells are sifted by the sieve of
natural selection, so that those few that are better at surviving and
reproducing in the environment we are creating with our vaccines will quite
quickly become the dominant form in the viral gene pool. A higher survival rate
is a consequence of becoming more infective, producing more viruses and/or
evading the immunity the vaccines are conferring on us.
Hospital Admissions (21 July 2021)
The significant factor here is that these mutations don't need to arise in
people who have been vaccinated; they only need to infect vaccinated people to
be selected for. So long as there are billions of people who have not been
vaccinated, there is a high probability that a billion to one chance mutation
will happen daily in the viral population numbered in the trillions. It is only
by massively reducing this breeding ground by vaccinating as many people as
possible that we can reduce the chance of these mutations arising.
The good news is, that, as the figures from the UK show, while new infections
are approaching figures last seen last January and February, the number of
hospitalisations and deaths are only a small fraction of what they were then.
The vaccines are working to prevent serious illnesses and deaths.
Menwhile, we can only wonder at the mindset of those fanatical Creationists who
are so full of admiration for what they believe to be the creator of this
terrible pandemic.
