Comparison of total antibody and interferon-γ T-cell responses in patients following infection with brucellosis in Georgia

Abstract

Summary: Brucellosis is an ancient disease that still remains a significant threat to humans and is typically linked to exposure to infected animals and/or consumption of unpasteurized animal products. Despite this history, we have a relatively limited understanding of the host characteristics of this disease; consequently, further research is necessary. In this study, we examined the humoral immune response in 43 Georgian individuals that had been diagnosed with brucellosis 3–12 months before enrollment in the study, many of whom still had symptoms after the completion of antibiotic therapy. In total, 35 of 43 (83%) of the patients had antibodies that bound to Brucella lipopolysaccharide (LPS) by COMPELISA, and 34 of 38 (89%) patients had demonstrable specific antibodies to Brucellergene™ antigens; the results from the two ELISAs were highly correlated (p = 0.031, r = 0.851). We also studied the cellular immune responses in 15 patients. All of the patients generated interferon (IFN)-γ in response to ex vivo stimulation with Brucella protein antigens, and the majority of the patients maintained measurable humoral responses to both LPS and protein antigens. From this initial study, we conclude that measurement of antibody and of cellular (IFN-γ) responses to brucellergene OCB protein epitopes may be worthy of further investigation as an alternative or adjunct to current diagnostics. Keywords: Brucella, Immune response, ELISPOT, ELISA, Brucellin, LPS