Porcine Serum amyloid A ELISA Kit

The serum amyloid A (SAA) gene family is highly conserved and encodes acute phase proteins that are upregulated in response to inflammatory triggers. Over the years, a considerable amount of literature has been published attributing a wide range of biological effects to SAAs such as leukocyte recruitment, cytokine and chemokine expression and induction of matrix metalloproteinases. Furthermore, SAAs have also been linked to protumorigenic, proatherogenic and anti-inflammatory effects. Here, we investigated the biological effects conveyed by murine SAA3 (mu rSAA3) recombinantly expressed inEscherichia coli. We observed the upregulation of a number of chemokines including CCL2, CCL3, CXCL1, CXCL2, CXCL6 or CXCL8 following stimulation of monocytic, fibroblastoid and peritoneal cells with mu rSAA3. Furthermore, this SAA variant displayed potentin vivorecruitment of neutrophils through the activation of TLR4. However, a major problem associated with proteins derived from recombinant expression in bacteria is potential contamination with various bacterial products, such as lipopolysaccharide, lipoproteins and formylated peptides. This is of particular relevance in the case of SAA as there currently exists a discrepancy in biological activity between SAA derived from recombinant expression and that of an endogenous source, i.e. inflammatory plasma. Therefore, we subjected commercial recombinant mu rSAA3 to purification to homogeneity via reversed-phase high-performance liquid chromatography (RP-HPLC) and re-assessed its biological potential. RP-HPLC-purified mu rSAA3 did not induce chemokines and lackedin vivoneutrophil chemotactic activity, but retained the capacity to synergize with CXCL8 in the activation of neutrophils. In conclusion, experimental results obtained when using proteins recombinantly expressed in bacteria should always be interpreted with care.

The objective of this study was to evaluate the serum protein pattern and selected acute phase proteins in dairy cows with chronic diarrhoea associated with seropositivity to Mycobacterium avium subsp. paratuberculosis (MAP). Forty-four dairy cows with chronic diarrhoea and MAP-seropositive and 19 clinically healthy MAP-seronegative cows were included in the study. The concentrations of total protein (TP), protein fractions and selected acute phase proteins - serum amyloid A (SAA), haptoglobin (Hp) and C-reactive protein (CRP) were measured in blood serum. In cows with diarrhoea the mean values of TP, albumin and the albumin/globulin ratio were significantly lower (P < 0.001), the relative concentrations of alpha(1)-, beta(1)- and gamma-globulins were significantly (P < 0.001) and alpha(2)- and beta(2)-globulins were non-significantly higher. The electrophoretic pattern of serum proteins showed beta-gamma bridging in 32 from 44 diseased cows. The concentrations of SAA and Hp were non-significantly higher and CRP significantly lower (P < 0.001) in cows with diarrhoea. Presented results indicate a marked effect of chronic diarrhoea in MAP-seropositive cows on the protein metabolism suggesting possible diagnostic significance of some biomarkers from the protein profile in the evaluation of the severity of the disease and changes caused by this protein-losing enteropathy.