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PhD defence: Alexey Ferapontov

Molecular Requirements for Antigen-driven B cell Activation

Info about event

Time

Tuesday 3 May 2022,  at 13:00 - 15:00

Location

Eduard Biermann Aud. (1252-204), Aarhus University, Bartholins Allé 3, 8000 Aarhus C

On Tuesday 3 May at 13:00, Alexey Ferapontov defends his PhD dissertation entitled "MOLECULAR REQUIREMENTS FOR ANTIGEN-DRIVEN B CELL ACTIVATION".

B cells play a vital role in the adaptive immune response by generating antigen-specific antibodies. The first step in the B cell response is antigen binding by B cell receptors (BCRs) on cognate B cells. Throughout the past decades of immunological research, various theories have developed regarding the binding of antigen through BCR and followed B cell activation. Some activation models based on these theories propose activation by both monovalent and polyvalent antigens. Others suggest that only polyvalent antigens can activate B cells. Despite intense scrutiny between these models, there is still no consensus on the molecular mechanism of BCR activation. Here, a novel model of antigen technology, namely the Holliday junction nano-scaffolds, was used to engineer monodisperse antigens with high precision-controlled affinity and valency and probed the minimal requirements for BCR activation.

While monovalent antigens at supraphysiological levels could induce activation, at concentrations approaching equimolar stoichiometry, they did not. In contrast, multivalent antigen-activated B cells at levels well below receptor saturation. Using various techniques, including cellular imaging and flow cytometry, I show that even though both polyvalent and monovalent antigens can bind to B cells through BCRs, only polyvalent antigens can activate them at physiologically relevant levels. Taken together, these findings suggest that B cell activation through BCRs is dependent on multiple factors, including valency, affinity, stoichiometry, and the nature of antigens.

The summary is written by the PhD student.

The defence is public and takes place in the Eduard Biermann Aud. (1252-204), Aarhus University, Bartholins Allé 3, 8000 Aarhus C . Please read the attached press release for more information.

Contact

PhD student Alexey Ferapontov

Mail: alexf@biomed.au.dk

Phone: (+45) 23110509

Read full press release