Effect of GP19 Peptide Hyperimmune Antiserum on Activated Macrophage during Ehrlichia canis Infection in Canine Macrophage-like Cells

Abstract

In terms of its veterinary importance, vaccine development against Ehrlichia canis is needed. However, the effect of developing vaccines on humoral immune response against E. canis infection is still unknown. Novel GP194-43 was synthesized according to E. canis GP19 epitope prediction. To restrict any loss and/or illness in the host animal, rabbits were used in this study to produce GP194-43 hyperimmune sera. The effect of GP194-43 hyperimmune sera on neutralization was examined in vitro by determining the inhibition of E. canis infection of the macrophage-like cell line (DH82) in the presence of the sera. Four groups of DH82 cells received differing treatments. These included E. canis experimentally infected DH82 cells, E. canis-infected DH82 cells with control rabbit serum (untreated group), E. canis-infected DH82 cells with GP194-43 rabbit antiserum (treated group) and uninfected cells (negative control group), respectively. The treated group developed a decrease (p < 0.01) in the percentage of E. canis infected cells after 3 days post-infection at 48.57 ± 1.28. In addition, real-time PCR analyses of cytokine mRNA expression involved with the macrophage, humoral, and cellular immune responses were conducted. The findings revealed an upregulated expression of IFNG in the treated group during the infection. This study demonstrated neutralization in the GP194-43 peptide hyperimmune sera of immunized rabbits. Notably, IFN-γ production could be effectively promoted in canine macrophages in relation to the activation of macrophages and adaptive immune responses. The results of this study indicate the potential for the use of this immunogen in further investigations involving immunized and infected dogs as E. canis host species.

Recombinant Ehrlichia canis GP19 Protein as a Promising Vaccine Prototype Providing a Protective Immune Response in a Mouse Model

“…The possible linkages of cytokine expressions resulting from macrophages and cell-mediated immune response against intracellular microorganisms including E. canis are shown in Figure 7. Additionally, * represents the cytokine expression at the molecular level in this study and previous study [13].…”

“…The present studies provided evidence of rGP19 that can eliminate E. canis by manipulating both humoral and phagocyte cell-mediated immune responses in a laboratory animal model. Additionally, * represents the cytokine expression at the molecular level in this study and previous study [13].…”

“…Cytokine network involved macrophage, T cell (CD4+ and CD8+) and B cell activation in the immune response against Ehrlichia canis. Abbreviations: 4-1BBL: 4-1BB ligand; APRIL: a proliferation-inducing ligand; CD: cluster of differentiation; IFN: interferon; IL-: interleukin; MIF: macrophage migration inhibitory factor; TNF: tumor necrosis factor; TGF: transforming growth factor.Additionally, * represents the cytokine expression at the molecular level in this study and previous study[13].…”

“…E. canis BF W053712 X + 5 (PTA-5811™, ATCC ® , Manassas, VA, USA) was cultured in DH82 canine macrophage cells at 37 • C and 5% CO 2 as previously described [13]. DH82 cells with intracellular bacteria, E. canis, were propagated until 80% of infected cells were reached.…”