The impact of Escherichia coli contamination products present in recombinant African horse sickness virus serotype 4 proteins on the innate and humoral immune responses

• Published in: Molecular immunology 2022-12, Vol.152, p.1-13
• Main Authors: Faber, Erika, Tshilwane, Selaelo Ivy, Van Kleef, Mirinda, Pretorius, Alri
• Format: Article
• Language: English
• Subjects: Endotoxin tolerance; Escherichia coli; Hyperinflammation; Innate-like B cells; Lipopolysaccharide; Polyreactive (natural) antibodies; Recombinant proteins
• ISSN: 0161-5890; 1872-9142
• DOI: 10.1016/j.molimm.2022.09.013

Transcriptome analysis was used to characterise the in vitro primary and secondary immune responses induced in horse peripheral blood mononuclear cells (PBMC) stimulated for 24 h with the individual recombinant proteins of a virulent AHSV serotype 4 (AHSV4) field isolate (rAHSV4 proteins) that were previously expressed in Escherichia coli (E. coli). The results showed that the E. coli contamination products greatly affected the innate and humoral immune response transcripts. Hence, the impact of E. coli contamination products present in the individual rAHSV4 proteins on the translational immune response was determined. The combined amplification effects of synergistic pattern recognition receptors (PRRs), TNF-α and IL-1β signalling induced potent pro-inflammatory responses that were too overwhelming for the anti-inflammatory cytokines and regulators to control. In addition to inducing robust B cell and antibody-mediated responses, lipopolysaccharide (LPS) activation of the innate-like B cells and subsequent polyreactive (natural) antibody responses could potentially contribute to endotoxin tolerance. •E. coli contamination products in recombinant proteins effect the immune response.•Synergistic PRR and cytokine signalling may result in hyperinflammation.•LPS induced robust innate-like B cell and polyreactive antibody-mediated responses.•Antibody responses of innate-like B cells may contribute to endotoxin tolerance.•Experimental data could be misinterpreted due to E. coli contamination.