The porcine memory B cell in conferring long term adaptive immunity to viral pathogens

Abstract

Porcine reproductive and respiratory syndrome virus (PRRSV) is the most important pathogen of swine health and well-being worldwide. Discovered nearly thirty years ago, there is still no vaccine capable of producing a broadly protective immune response against the virus. This deficiency is due in large part to a failure to understand how the adaptive immune system responds to vaccination or infection. Specifically, there is little to no knowledge regarding the all-important memory immune response to PRRSV. The objective of this dissertation was to fill in this significant gap in knowledge by identifying and characterizing the memory B cell response to PRRSV vaccination. First, we identified the presence of memory B cells against PRRSV non-structural protein 7 (nsp7) through the use of a novel in vitro B cell culture system. Next, we created and validated a novel reagent, a B cell tetramer, against nsp7 to enhance the speed and sensitivity of memory cell identification. Finally, through the utilization of the nsp7 tetramer, we evaluated the regional specificity and dynamic nsp7 specific B cell response to PRRSV MLV vaccination within select secondary lymphoid organs. These results constitute the first evidence of regional specialization of the B cell response to vaccination in an outbred animal species. Furthermore, the presented methods are a blueprint for the study of antigen specific cellular responses to any significant pathogen of animals important for food or fiber.