We found that Strep A infection induced sugar B cells to enter the Germinal centre where they became highly mutated.

How were they doing this? By comparing to protein responses (SpyCEP) we found that sugar B cells had a molecular signature consistent with receiving reduced T cell help.

By studying human blood, spleen and tonsils, including samples from a Strep A human challenge model, we show that sugar B cell responses shift from IgM
towards IgG and IgA memory with age and antigen exposure.

We asked - is this dogma correct when sugar-specific B cells could engulf whole bacteria? (that contain proteins for T cells to recognise).

We focussed on Strep A, where the sugar (GAC) is a leading glycoconjugate vaccine candidate.

Image: Natalia Korotkova

New preprint alert 🚨

My team and I are pleased to share our most recent story about how bacterial pathogen (Streptococcus pyogenes, Strep A) exposure induces antibody responses against glycan and protein antigens.

For paper: SSRN ssrn.com/abstract=519...
biorxiv : doi: doi.org/10.1101/2025...

I’ll take this opportunity to announce that I’ll have multiple postdoc positions opening early next year.

Come join us in Melbourne! 🇦🇺🐨🦘
If you’re interested in mucosal immunology, microbiology, parasitology, vaccine design or bioinformatics, get in touch ✉️!
#ImmunoSky #MicroSky #IDSky

Overall, we find that past exposure to this ubiquitous pathogen leaves a complex humoral imprint. There is MUCH more data in the paper for #Strep A enthusiasts.

We are particularly excited about finding baseline antibody signatures that associate with susceptibility or resistance to pharyngitis.

"But does a human challenge mimic a real infection?" I hear you ask.

We need a #Strep A vaccine to work for kids. We found that the magnitude of antibody made in the human challenge was similar to what children make 1 month after natural pharyngitis.

We found pharyngitis participants mounted serum IgG responses to key vaccine antigens and a muted mucosal IgA response.

When we did see IgG responses, they were maintained for at least 3 months.

In this model, healthy volunteers had bacteria applied to the pharynx and 19/25 went on to develop pharyngitis days later.

We studied antibody responses in serum and saliva at 1wk and 1month post challenge, and most importantly, we could look at what immunity was present prior to infection.

The new paper is about immune responses to Streptococcus pyogenes #StrepA, a bacteria that causes Strep throat, invasive infections, and in some people can cause an autoimmune disease, rheumatic fever, overall resulting in ~500,000 deaths/year globally.

There is still no Strep A #vaccine. 💉

🎉 I'm a #newPI , and I'm so excited to share our new paper out in Nature Comms today! 🧵
rdcu.be/d2gBV
Quick intro for the new followers:
I'm from Monash Uni in Melbourne, and we study T and B cell responses to viruses, bacteria & parasites with the goal of improving vaccines. #ImmunoSky #MicroSky