钙网蛋白的免疫生物学活性研究进展

钙网蛋白(calreticulin,CRT)是内质网中的Ca2+结合蛋白,对维持细胞内的Ca2+稳态具有重要作用。CRT还可作为分子伴侣,帮助新合成的内质网蛋白正确折叠。除此之外,CRT还出现在细胞膜表面及细胞外环境中,并发挥重要的免疫调节作用。膜表面的CRT参与凋亡细胞的清除和抗肿瘤免疫应答,在T细胞活化早期也发挥重要作用。可溶性CRT出现在自身免疫病患者的血清中,且其浓度与疾病活动度相关。重组可溶性CRT腹腔注射可显著影响小鼠的Th1/Th2平衡。重组可溶性CRT分子不仅具有超强免疫刺激活性,还表现出很强的佐剂效应,提示可溶性CRT可能在自身免疫性疾病的发生与发展过程中发挥一定作用。可以预见,CRT分子的免疫生物学活性将在不久的将来成为该领域研究的一个热点。

Immunological Activities of Calreticulin

Calreticulin(CRT) is an ER protein that can regulate Ca2+ homoeostasis of the cell.It also functions as a molecular chaperon assisting correct folding of newly synthesized proteins in the ER.Recent advances demonstrate that CRT can exist in both membrane-bound and soluble forms and exhibit potent immunobiological activities as well.Cell surface CRT(csCRT) of phagocytes participates in eradicating apoptotic cells and immune response against tumor cells.csCRT also plays important roles in early activation of T cells.Soluble CRT can be detected in the sera of patients with rheumatoid arthritis or systemic lupus erythematosus,which is underlined by the fact that recombinant soluble CRT is a potent stimulator of B cells and macrophages in vitro and a strong immunogen in vivo.Administration of recombinant CRT skews Th1/Th2 balance in mice.CRT is also a potent adjuvant capable of helping adaptive immune responses against target antigens in vivo.It is predictable that immuno-biological activities of CRT will become a focus in the future research on this multifunctional protein.