一种精子蛋白嵌合肽的实验研究

Immunocontraceptive effect of a synthetic chimeric peptide of sperm

目的 探讨可供两性使用的免疫避孕疫苗的可能性。方法 设计含有小鼠精子 /睾丸特异性抗原SP17、Cyritestin中特异性氨基酸序列的新抗原 35肽。经合成、鉴定及纯化后 ,免疫雌性Balb/C小鼠 ,并了解其免疫原性 ,同时观察其抗生育效应。结果 获得的新抗原 35肽经质谱鉴定证实其合成正确 ,经高压液相色谱 (KPLC)纯化后纯度达 95 %以上 ;嵌合肽与钥孔血蓝蛋白 (KLH)偶联后免疫小鼠获得的特异性抗血清可识别小鼠、大鼠及人睾丸组织蛋白提取物中相对分子质量的蛋白质 ;与等量弗氏佐剂混悬后免疫小鼠 ,其血清中特异性IgG抗体滴度最高达 1∶6 0 0 0 ,阴道粘膜冲洗液中特异性IgA抗体滴度最高达 1∶30 0 ;免疫后小鼠受孕率降至 6 1.11% ,平均每胎产仔量也减至 4 .3只。结论 新抗原 35肽可在雌性Balb/C小鼠体内激发出较强的特异性体液和粘膜免疫 ,使小鼠受孕率和每胎产仔数明显下降。

Objective To investigate the immunocomtraceptive ability of a new synthetic chimeric peptide with 35 amino acid residues. Methods A chimeric peptide with 35 amino acid residues was synthesized based on the amino acid sequence of SP17, a protein specific to murine testis/sperm, and cyritestin. The purified product, with keyhole limpet hemocyanin (KLH), was injected subcutaneously into the pad of female and male Balh/C mice. Blood was extracted from the ophthalmic arteries of the mice to identify the corresponding proteins from organs of mice and/or rat and human being by Western blotting. The chimeric peptide was injected into other famale mice that were then raised together with male mice in the same cages to observe their status of pregnancy. Freund′ adjuvant or normal saline were injected into the controls. Results The purity of the new chemiric peptide was 95%. The highest specific IgG titre in mouse serum was 1: 6000 and the highest titre of specific IgA in the washing of vaginal mucous membrane of famale mice was 1:300. The specific antiserum from the mice immunized by the chimeric peptide and KLH could identify two proteins with the molecular weights of 22 000 and 55 000 from testes of mice, rats, and human being. Western blotting showed no band for the extracts of mouse liver, spleen, and kidney. The pregnancy rate of female immunized mice was 61.11%, significantly lower that those in the controls ( P <0.05). The average number of cubs in a litter was less in the experimental group than in the controls ( P <0.05). Conclusion The new chimeric peptide with 35 amino acid residues stimulates powerfully humoral and mucous immunity in mice and obviously decreases the pregnancy rate and the number of cubs in each litter in mice.