Identification of a novel mechanism of action of bovine IgG antibodies specific for Staphylococcus aureus

Abstract

Staphylococcus aureus is a major pathogen that causes subclinical mastitis associated with huge economic losses to the dairy industry. A few vaccines for bovine mastitis are available, and they are expected to induce the production of S. aureus-specific antibodies that prevent bacterial adherence to host cells or promote opsonization by phagocytes. However, the efficacy of such vaccines are still under debate; therefore, further research focusing on improving the current vaccines by seeking additional mechanisms of action is required to reduce economic losses due to mastitis in the dairy industry. Here, we generated S. aureus-specific bovine IgG antibodies (anti-S. aureus) that directly inhibited bacterial growth in vitro. Inhibition depended on specificity for anti-S. aureus, not the interaction between Protein A and the fragment crystallizable region of the IgG antibodies or bacterial agglutination. An in vitro culture study using S. aureus strain JE2 and its deletion mutant JE2ΔSrtA, which lacks the gene encoding sortase A, revealed that the effect of anti-S. aureus was sortase-A-independent. Sortase A is involved in the synthesis of cell-wall-associated proteins. Thus, other surface molecules, such as membrane proteins, cell surface polysaccharides, or both, may trigger the inhibition of bacterial growth by anti-S. aureus. Together, our findings contribute insights into developing new strategies to further improve the available mastitis vaccine by designing a novel antigen on the surface of S. aureus to induce inhibitory signals that prevent bacterial growth.Electronic supplementary materialThe online version of this article (10.1186/s13567-018-0517-y) contains supplementary material, which is available to authorized users.

Tropical study on Clinical and Host Cell Responses of Acute Phase Proteins, Pro-Inflammatory Cytokines and Antibodies’ in Lactating Dairy Cows Vaccinated and Challenged with S. aureus

“…In another related study conducted by [72], the study concluded that serum IgG and IgM were signi cantly high during post-vaccination in the vaccinated group than in the control group indicative of vaccine-induced opsonisation in the treatment group. Total IgG elevation in vaccinated group post-vaccination and challenge as observed in the vaccinated group of the current study corroborate with the report of [73], who proved that IgG antibodies increased during post-vaccination or challenge period. In another related experimental study on the generation of a novel S. aureus ghost vaccine and examination of its immunogenicity against the virulent challenge, the IgG titer increased robustly at weeks 2, 4, 6 post-vaccination [74].…”

Organic Selenium Ameliorates Staphylococcus aureus-Induced Mastitis in Rats by Inhibiting the Activation of NF-κB and MAPK Signaling Pathways

“…Although vaccines have been used to prevent mastitis caused by S. aureus , bovine mastitis mainly depends on antibiotic treatment. However, neither is effective in preventing S. aureus mastitis ( 9 ). Furthermore, ineffective treatment can also induce antimicrobial resistance in bacteria and drug residue in the products ( 10 ).…”

Novel luminescent affiprobes for molecular detection of Staphylococcus aureus using flow cytometry

“…2013) and labelled anti‐SpA antibodies have been used for detection of S. aureus using ELISA and flow cytometry (Nuding 2013; Furukawa et al . 2018). The limitation of these methods are low stability, difficult purification and modification, and the high cost of antibodies (Shahdordizadeh et al .…”

“…2015) and has been targeted by a variety of proteins including labelled anti‐protein A antibodies (Nuding 2013; Furukawa et al . 2018), single domain antibodies (Ryan et al, 2009) and Affibodies (Lindborg et al . 2013).…”