A new role for complement C3: regulation of antigen processing through an inhibitory activity

Immunomodulatory Effects of Saccharomyces cerevisiae Fermentation Product Supplementation on Immune Gene Expression and Lymphocyte Distribution in Immune Organs in Broilers

A study was conducted to evaluate the molecular and cellular immunomodulatory effects of a Saccharomyces cerevisiae fermentation product (Original XPC, Diamond V) in broilers. Our lab has previously demonstrated that broilers fed XPC generate faster and stronger antigen-specific humoral immune responses to Newcastle disease virus (NDV) vaccination. This study aims at investigating the mechanism behind this increased immunocompetence. One-day-old broilers were randomly assigned to one of two treatments: 1.25 kg/ton S. cerevisiae fermentation product (XPC treatment group) or control diet. Birds were vaccinated against NDV on day 1 (B1 strain) and day 21 (LaSota strain) post-hatch. Innate and adaptive immune-related gene expression profiles in central (thymus and bursa of Fabricius) and peripheral (spleen) immune organs were investigated at 14 and 28 days of age by qPCR array. Fold changes larger than 1.2 (P < 0.05) between treated and control were considered significant. Lymphocyte subpopulations in central and peripheral immune organs and blood leukocytes were analyzed by flow cytometry at 14, 21, 28, and 42 days of age. In the spleen, Th1 immune responses and antiviral genes, such as IFN-γ, and its downstream genes signal transducer and activator of transcription (STAT4) and NFκB, were significantly upregulated in the treated group by 14 days of age. In the thymus, genes belonging to different functional groups were influenced at different time points. Cytokine genes associated with lymphocyte maturation, differentiation, and proliferation, such as IL-1R, IL-2, and IL-15 were significantly upregulated in the treated group by 28 days of age. Genes preferentially expressed in the medulla of the thymus and mature thymocytes, such as Myxovirus resistance gene 1, interferon regulatory factor-1, interferon regulatory factor-7, and STAT1, were upregulated in the birds supplemented with XPC. Birds supplemented with XPC had significantly higher percentages of CD3+, CD4+, and CD8+ T-cells in the thymus at day 28 of age, indicating production of more mature T-cells, which was consistent with gene expression results. Results suggest that XPC supplementation primes broilers to become more immunocompetent, without compromising growth performance.

Identification of potential serum biomarkers in pigs at early stage after Lipopolysaccharide injection

The identification of useful biological indicators to monitor the body response before the presentation of clinical diseases has practical value in livestock production. To identify potential biomarkers in pigs at the early stage during inflammation, 12 pigs were intramuscularly injected with 2mL of Lipopolysaccharide (LPS, 15μg/kg BW) or saline. Serum protein expression profiles were detected with two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) techniques. Serum biochemical indicators and acute phase protein (APP) concentrations were analyzed with an automatic biochemical analyzer and ELISA, respectively. Of the serum biochemical indicators, creatinine concentration significantly increased 6h post infection, whereas albumin showed a decreased tendency. The 2-DE and MALDI-TOF mass spectrometry technique detected 17 protein spots representing 10 proteins: α-1-antichymotrypsin, albumin, bovine lactoferrin, serotransferrin, serpin A3-6, immunoglobulin light chain (κ chain, mu chain), complement C3 precursor, zinc-α-2-glycoprotein (ZAG), and ceruloplasmin. Two proteins were selected to confirm the mass spectrometry results, and resulting differences accorded with the proteomics results. Of the four typical acute phase protein (APPs) measured, the C-reactive protein (CRP) and haptoglobin (HP) concentrations increased significantly, while no differences were observed in the pig-major acute phase protein (Pig-MAP) and transthyretin (TTR) contents. The results showed that serum creatinine, CRP, HP, and ten other proteins content changed significantly after LPS injection. Of these proteins, ZAG was first reported in pigs during inflammation. These proteins show great promise as biomarkers to monitor the health status and welfare of pigs during the early stage of LPS-induced inflammation.

Plasma proteomic analysis of simian immunodeficiency virus infection of rhesus macaques

Lentiviral replication in its target cells affects a delicate balance between cellular cofactors required for virus propagation and immunoregulation for host defense. To better elucidate cellular proteins linked to viral infection, we tested plasma from rhesus macaques infected with the simian immunodeficiency viral strain SIVsmm9, prior to, 10 days (acute), and 49 weeks (chronic) after viral infection. Changes in plasma protein content were measured by quantitative mass spectrometry by isobaric tags for absolute and relative quantitation (iTRAQ) methods. An 81 and 232% increase in SERPINA1 was seen during acute and chronic infection, respectively. Interestingly, gelsolin, vitamin D binding protein and histidine rich glycoprotein were decreased by 45% in acute conditions but returned to baseline during chronic infection. When compared to uninfected controls, a 48-103% increase in leucine rich alpha 2-glycoprotein, vitronectin, and ceruloplasmin was observed during chronic viral infection. Observed changes in plasma proteins expression likely represent a compensatory host response to persistent viral infection.

The role of salivary and intestinal complement system inhibitors in the midgut protection of triatomines and mosquitoes

Saliva of haematophagous arthropods contain biomolecules involved directly or indirectly with the haematophagy process, and among them are encountered some complement system inhibitors. The most obvious function for these inhibitors would be the protection of the midgut against injury by the complement. To investigate this hypothesis, Triatoma brasiliensis nymphs were forced to ingest human serum in conditions in which the protection of midgut by the inhibitors is bypassed. In these conditions, the anterior midgut epithelium was injured by the complement, causing cell death. Once some insects such as Aedes aegypti have no salivary inhibitors, we hypothesized the existence of intestinal inhibitors. The inhibitory activity was investigated in the intestine of A. aegypti as well as in the saliva and intestine of other three triatomine species (T. brasiliensis, T. infestans and Rhodnius prolixus) using an immunological method able to determine the level of deposition of some complement factors (C1q, C3b, or C4b) on the surface of complement activator molecules linked to microplates. This methodology permitted to identify which points along the activation phase of the complement cascade were inhibited. As expected, soluble contents of A. aegypti's intestine was capable to inhibit C3b deposition by the classical and alternative pathways. Saliva or soluble intestinal contents, obtained from triatomines were unable to inhibit C1q deposition by the classical pathway. C4b deposition by the classical pathway was inhibited by the intestinal contents from the three triatomines. On the other hand, only T. brasiliensis saliva inhibited C4b deposition. Both, saliva and intestinal contents from all triatomines were able to inhibit C3b deposition in the classical and alternative pathways. None of the material extracted from the intestinal cell membranes from the triatomines inhibited C3b deposition in the classical pathway. The existence of complement inhibitors may have important biological consequences which are discussed in detail.