African swine fever virus (ASFV) is a large and complex DNA virus that causes African swine fever

(ASF), a haemorrhagic disease of pigs with up to 100% mortality. No commercially licenced vaccine

or treatment is currently globally available. Antibody responses against ASFV have been shown to be

protective, but neutralisation is technically challenging to demonstrate and its role in protection is

controversial. Non-neutralising functions of ASFV-specific antibodies have been demonstrated, but the

role they play in ASFV infection is not well known.

This thesis developed a novel assay to investigate antibody-mediated complement-dependent

cytotoxicity (CDC) and used this assay to first demonstrate successful identification of sera with the

ability to mediate ASFV-specific CDC; and then to show that ASFV-specific CDC did not appear to

correlate with protection against ASF disease, nor with reduced protection against disease or induction

of chronic disease.

Investigation into the ability of ASFV-specific antibodies to inhibit haemadsorption (HAD), the binding

of red blood cells to ASFV-infected cells, showed that protein sequences of viral proteins CD2v and

pEP153R could be used as predictors of cross-inhibiting activity. This work also demonstrated further

evidence for the involvement of CD2v and pEP153R as mediators of HAD and suggested a role for

antibodies against these proteins in HAD inhibition.

Finally, this thesis developed a pipeline for the production and purification of recombinant ASFV

protein tetramers. These tetramers successfully detected ASFV antigen-specific B cells using flow

cytometry, showing potential for use to characterise the ASFV-specific B cell response.

This work has shown that the B cell response to ASFV is varied and complex. The novel methods

presented here will allow in-depth analysis of B cell responses to vaccine constructs and B cell

immunogenic proteins and will contribute to the development of a safe and effective ASFV vaccine.