COVID-19: The older you are, the more antibodies you have, study finds


Date:
November 8, 2021
Source:
Universite' de Montre'al
Summary:
Chemists looked at lab samples of patients who recovered from a
mild case of COVID-19 and found that those over 50 produced more
antibodies against the SARS-CoV-2 virus.



FULL STORY ==========================================================================
With the emergence of SARS-CoV-2 variants worldwide, the pandemic's
spread is accelerating. A research team led by Joelle Pelletier and Jean-Franc,ois Masson, both professors in Universite' de Montre'al's
Department of Chemistry, wanted to find out whether natural infection
or vaccination led to more protective antibodies being generated.


==========================================================================
In their study published today in Scientific Reports, they observe that
those who received the Pfizer BioNTech or AstraZeneca vaccine had antibody levels that were significantly higher than infected individuals. These antibodies were also effective against the Delta variant, which wasn't
present in Quebec when the samples were collected in 2020.

Masson, a biomedical instruments specialist, and Pelletier, a protein
chemistry expert, were interested in an understudied group: people who
have been infected by SARS-CoV-2 but were not hospitalized as a result
of the infection.

32 non-hospitalized COVID-19 positive Canadian adults Consequently,
32 non-hospitalized COVID-19 positive Canadian adults were recruited
by the Centre hospitalier de l'Universite' Laval 14 to 21 days after
being diagnosed through PCR testing. This was in 2020, before the Beta,
Delta and Gamma variants emerged.

"Everyone who had been infected produced antibodies, but older people
produced more than adults under 50 years of age," said Masson. "In
addition, antibodies were still present in their bloodstream 16 weeks
after their diagnosis." Antibodies produced after an infection by
the original, "native" strain of the virus also reacted to SARS-CoV-2
variants that emerged in subsequent waves, namely Beta (South Africa),
Delta (India) and Gamma (Brazil), but to a lesser extent: a reduction
of 30 to 50 per cent.



==========================================================================
A surprising reaction to the Delta variant "But the result that surprised
us the most was that antibodies produced by naturally infected individuals
50 and older provided a greater degree of protection than adults below 50,
" said Pelletier.

"This was determined by measuring the antibodies' capacity to inhibit the interaction of the Delta variant's spike protein with the ACE-2 receptor
in human cells, which is how we become infected," he added. "We didn't
observe the same phenomenon with the other variants." When someone who
has had a mild case of COVID is vaccinated, the antibody level in their
blood doubles compared to an unvaccinated person who has been infected
by the virus. Their antibodies are also better able to prevent spike-ACE-
2 interaction.

"But what's even more interesting," said Masson, "is that we have
samples from an individual younger than 49 whose infection didn't produce antibodies inhibiting spike-ACE-2 interaction, unlike vaccination. This suggests that vaccination increases protection against the Delta variant
among people previously infected by the native strain." Both scientists believe more research should be conducted to determine the best
combination for maintaining the most effective level of antibodies
reactive to all variants of the virus.



========================================================================== About this study "Cross-reactivity of antibodies from non-hospitalized
COVID-19 positive individuals against the native, B.1.351, B.1.617.2,
and P.1 SARS-CoV-2 spike proteins," by Jean-Franc,ois Masson et al,
was published on October 26 2021 in Scientific Reports.

The study was done in collaboration with Universite' Laval, the Centre hospitalier de l'Universite' Laval, He'ma-Que'bec and the National
Research Council of Canada. It was funded by the Canadian Institutes of
Health Research, the Natural Sciences and Engineering Research Council
of Canada, the National Research Council of Canada's Pandemic Response Challenge Program and the Canada Foundation for Innovation.

========================================================================== Story Source: Materials provided by Universite'_de_Montre'al. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Maryam Hojjat Jodaylami, Abdelhadi Djai"leb, Pierre Ricard, E'tienne
Lavalle'e, Stella Cellier-Goethebeur, Megan-Faye Parker,
Julien Coutu, Matthew Stuible, Christian Gervais, Yves Durocher,
Florence Desautels, Marie-Pierre Cayer, Marie Joe"lle de Grandmont,
Samuel Rochette, Danny Brouard, Sylvie Trottier, Denis Boudreau,
Joelle N. Pelletier, Jean- Francois Masson. Cross-reactivity of
antibodies from non-hospitalized COVID-19 positive individuals
against the native, B.1.351, B.1.617.2, and P.1 SARS-CoV-2
spike proteins. Scientific Reports, 2021; 11 (1) DOI:
10.1038/s41598-021-00844-z ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/11/211108081455.htm

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