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Investigating the effect of class-switched IgM anti-spike SARS-CoV-2 antibodies on immune function

Lindquist, Lovisa (2025) MOBN03 20242
Degree Projects in Molecular Biology
Popular Abstract
Better Antibodies, Brighter Outcomes for COVID-19

Since the outbreak of the COVID-19 pandemic, over 700 million cases have been reported globally. The disease is caused by an infection of a coronavirus. In response, the body naturally produces antibodies - the “knights” of the immune system - specifically adapted to recognise and attack the virus. Antibodies can also be made in the laboratory and administered directly to patients with ongoing infections as a treatment. Such therapies help to avoid severe illness, limit the spread to others, and are particularly useful in protecting patients with weakened immune systems by temporarily boosting the body’s natural defence.

Most existing COVID-19 antibody therapies are based on a... (More)
Better Antibodies, Brighter Outcomes for COVID-19

Since the outbreak of the COVID-19 pandemic, over 700 million cases have been reported globally. The disease is caused by an infection of a coronavirus. In response, the body naturally produces antibodies - the “knights” of the immune system - specifically adapted to recognise and attack the virus. Antibodies can also be made in the laboratory and administered directly to patients with ongoing infections as a treatment. Such therapies help to avoid severe illness, limit the spread to others, and are particularly useful in protecting patients with weakened immune systems by temporarily boosting the body’s natural defence.

Most existing COVID-19 antibody therapies are based on a single group: IgG. IgG antibodies are highly specific and work individually to target the virus. However, these treatments are becoming less effective against emerging viral variants such as Omicron. They also show limited activity in the lungs and airways where the virus replicates, meaning a lower overall efficacy. As a result, new therapeutic alternatives are urgently needed. One promising solution that instils hope is the use of another class of antibodies: IgM. IgM antibodies typically form pentamers - clusters of five - that act as a single large shield to block and capture multiple viruses simultaneously.

During this project, I engineered two COVID-19-fighting antibodies from an IgG to an IgM format. I also created a special ‘Stellabody’ variant: a modified IgG that forms star-shaped hexamers upon binding the virus. The Stellabody closely mimics both the structure and the behaviour of an IgM. The goal of this project was to compare how effectively the different antibodies can recognise the coronavirus and trigger other immune defences. The results show that both the shape and type of antibody had a large impact on their performance. Switching from an IgG to an individual IgM, even without forming clusters, enhanced the ability to bind to the virus and block entry into human cells. In contrast, the Stellabody variant did not improve binding, but was more effective at activating immune proteins, known as “complement proteins”, involved in killing and clearing the virus.

These findings show that redesigning existing antibodies can be a critical tool for developing more effective therapies. This knowledge is not only vital for treating COVID-19, but also for many other lung infections, and most importantly, for preventing future pandemic outbreaks.

Master’s Degree Project in Molecular Biology, 60 credits, 2025
Department of Biology, Lund University

Advisors: Pontus Nordenfelt & Berit Olofsson
Quantitative Immunobiology, Department of Clinical Sciences, Lund University (Less)
Please use this url to cite or link to this publication:
author
Lindquist, Lovisa
supervisor
organization
course
MOBN03 20242
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
9212278
date added to LUP
2025-09-12 12:24:45
date last changed
2025-09-12 12:24:45
@misc{9212278,
  author       = {{Lindquist, Lovisa}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Investigating the effect of class-switched IgM anti-spike SARS-CoV-2 antibodies on immune function}},
  year         = {{2025}},
}