Complement C3/C3a 蛋白, Human

Complement C3/C3a protein plays a key role in initiating the complement system through processing by C3 convertase in both the classical and alternative pathways. Complement C3/C3a protein is involved in various immune and inflammatory responses and also has a role in regulating blood pressure. Complement C3/C3a Protein, Human is a recombinant Complement C3/C3a protein expressed in E. coli, untagged, and consists of 77 amino acids (S672-R748)^{[1][2][3][4][5][6][7][8][9][10][11]}.

Complement C3 可以通过 C3 转化酶或在炎症部位的血液蛋白酶 (如凝血酶) 和免疫细胞源性蛋白酶 (如半胱氨酸蛋白酶) 进行切割，产生两个分裂产物，Complement C3/C3a 和Complement C3/C3b。Complement C3/C3a 参与多种免疫和炎症反应，在不同免疫细胞中具有双向的作用，可能通过不同的机制影响免疫反应和疾病过程^[1][2]。
(a) 在单核细胞和巨噬细胞中，Complement C3/C3a 通过TLR-4介导，促进这些细胞产生促炎介质，如IL-1β、TNF-α、IL-6 和 PGE2。(b) 在肥大细胞中，Complement C3/C3a 诱导组胺的脱颗粒反应；(c) 在嗜酸性粒细胞中，它则刺激钙动员、氧化爆发和脱颗粒。(d) 此外，Complement C3/C3a 通过抑制动员因子的作用，减少中性粒细胞进入血液循环，从而抑制其迁移。(e) Complement C3/C3a 在大脑炎症期间的脑内皮激活和白细胞募集中也起着关键作用。(f) Complement C3/C3a 通过与抗原呈递细胞 (APC) 和 T 细胞上受体 C3aR 相互作用，可以直接或间接改变 T 细胞反应^[3][4][5][6]。
Complement C3/C3a 存在于血浆衍生的 FVIII 产物中，可在人树突状细胞 (DC) 中促进由 pdFVIII (从血浆中提取的 FVIII 产物) 和脂多糖 (Lipopolysaccharides, HY-D1056) 介导的 T 细胞增殖。^[7]。
此外，Complement C3 被报道具有抗氧化应激活性，可保护人支气管上皮细胞免受香烟烟雾诱导的氧化应激，并抑制细胞凋亡 (Apoptosis)^[7]。

Complement C3/C3a (Human) (2 μg / mL) 可提高人足细胞中 NF-κB 和 IL-1β 表达^[9]。
Complement C3/C3a (Human) (200 ng/mL，2 小时) 通过激活 p38 MAPK 和NF-κB 磷酸化，在 Lipopolysaccharides (HY-D1056) 诱导的小鼠原代脑内皮细胞中上调 VCAM-1 和 ICAM-1 表达，从而发挥抗炎作用^[11]。

Complement C3/C3a (Human) 受体拮抗剂 (JR14a) (10mg/kg，灌胃，每日一次持续 7 天) 可降低抗 Fx1A 抗体诱导的Heymann 肾炎大鼠模型的蛋白尿水平，说明 C3a 是其体内促炎因子^[9]。

Measured by its ability to enhance IL-6 secretion by THP-1 human acute monocytic leukemia cells. The ED₅₀ for this effect is ≤0.4476 μg/mL, corresponding to a specific activity is ≥2234.1376 U/mg.

• 
  Measured by its ability to enhance IL-6 secretion by THP-1 human acute monocytic leukemia cells. The ED₅₀ for this effect is 0.1759 μg/mL, corresponding to a specific activity is 5685.0483 U/mg.

Human

E. coli

Tag Free

P01024 (S672-R748)

718  [NCBI]

SVQLTEKRMDKVGKYPKELRKCCEDGMRENPMRFSCQRRTRFISLGEACKKVFLDCCNYITELRRQHARASHLGLAR

Approximately 13.0 kDa

• 
  Greater than 95% as determined by reducing SDS-PAGE.

无菌粉末

Lyophilized from a 0.2 μm filtered solution of 20 mM PB, 150 mM NaCl, pH 7.4.

<1 EU/μg, determined by LAL method.

It is not recommended to reconstitute to a concentration less than 100 μg/mL in ddH₂O. For long term storage it is recommended to add a carrier protein (0.1% BSA, 5% HSA, 10% FBS or 5% Trehalose).

Stored at -20°C for 2 years. After reconstitution, it is stable at 4°C for 1 week or -20°C for longer (with carrier protein). It is recommended to freeze aliquots at -20°C or -80°C for extended storage.

Room temperature in continental US; may vary elsewhere.

• [1]. Coulthard LG, et al. Is the complement activation product C3a a proinflammatory molecule? Re-evaluating the evidence and the myth. J Immunol. 2015 Apr 15;194(8):3542-8.  [Content Brief]

  [2]. Markiewski MM, et al. Complement and coagulation: strangers or partners in crime? Trends Immunol. 2007 Apr;28(4):184-92.  [Content Brief]

  [3]. Wu F, et al. Complement component C3a plays a critical role in endothelial activation and leukocyte recruitment into the brain. J Neuroinflammation. 2016 Jan 28;13:23.  [Content Brief]

  [4]. Kubota Y. 1992. The effect of human anaphylatoxins and neutrophils on histamine release from isolated human skin mast cells. J. Dermatol. 19: 19–26.

  [5]. Asgari E., et al. 2013. C3a modulates IL-1β secretion in human monocytes by regulating ATP efflux and subsequent NLRP3 inflammasome activation. Blood 122: 3473–3481.

  [6]. Daffern P. J., et al. 1995. C3a is a chemotaxin for human eosinophils but not for neutrophils. I. C3a stimulation of neutrophils is secondary to eosinophil activation. J. Exp. Med. 181: 2119–2127.

  [7]. Ringler E, et al. Complement protein C3a enhances adaptive immune responses towards FVIII products. Haematologica. 2023 Jun 1;108(6):1579-1589.  [Content Brief]

  [8]. Pei Y, et al. Complement component 3 protects human bronchial epithelial cells from cigarette smoke-induced oxidative stress and prevents incessant apoptosis. Front Immunol. 2022 Dec 20;13:1035930.  [Content Brief]

  [9]. Gao S, et al. Complement C3a and C3a Receptor Activation Mediates Podocyte Injuries in the Mechanism of Primary Membranous Nephropathy. J Am Soc Nephrol. 2022 Sep;33(9):1742-1756.  [Content Brief]

  [10]. Lillegard KE, et al. Differential effects of complement activation products c3a and c5a on cardiovascular function in hypertensive pregnant rats. J Pharmacol Exp Ther. 2014 Nov;351(2):344-51.  [Content Brief]