B ANC C CLASS CpG PROTECT AGAINST INTRANASAL CHALLENGE BY B. PSEUDOMALLEI IN A MOUSE MODEL

Katie Taylor^1,2, A. Deeraksa, Ph.D.², B.Judy, Ph.D.², A. Torres, Ph.D.³, and M. Estes, Ph.D.^2,3

¹Departments of Pathology, ²Pediatrics; ³Sealy Center for Vaccine Development, ⁴Department of Microbiology and Immunology, UTMB

Background: Different CpG oligodinucleotides (CpG ODN) motifs are known to both influence the adaptive immune response in specific ways and enhance resistance to infection in many animal models. B-class CpG ODN are known to strongly induce B-cell proliferation whereas C-class CpG ODN exerts similar effects, but of lesser magnitude, while also inducing IFN-α. The correlates for protection mediated by the adaptive immune response during Burkholderia pseudomallei infection remain poorly characterized. Objective: The objective of this study was to determine the effects of different CpG classes on survival following lethal challenge with B. pseudomallei. Methods: BALB/c mice were primed with CpG B-class or C-class ODN 48 h prior to intranasal challenge with a lethal dose of B. pseudomallei. Results: Our results show that prior administration of either B or C class CpG provide strong protection against B. pseudomallei challenge. However, only B-class CpG primed mice had a major reduction in bacterial burden in the spleen. Conclusions: The data suggests that adjuvants capable of inducing a B-cell humoral immune response will be more effective against B. pseudomallei infection. This project was funded through the National Institutes of Health Western Regional Center of Excellence and the Foreign Animal and Zoonotic Disease Center of Excellence by a grant from the Department of Homeland Security, Science and Technology Directorate, Office of University Programs.