HIV-1 Gag抗原HLA-A*0201限制性低亲和性CTL表位预测及改造分析

Prediction and modificatory analysis on the HLA-A~*0201 restricted CTL epitopes with low affinity from HIV-1 Gag antigen

初步筛选HIV-1 Gag抗原的HLA-A*0201限制性低亲和性CTL表位,预测并初步鉴定修饰后的表位与HLA-A*0201之间亲和性的变化。采用超基序、蛋白酶解预测等相结合的办法筛选HLA-A*0201限制性低亲和性CTL表位,通过氨基酸置换适当修饰,并以T2细胞株测定肽与HLA-A*0201分子的亲和力和稳定性试验来评价修饰后表位与HLA-A*0201之间亲和性。结果:筛选出3个低亲和性CTL候选表位,经修饰后的表位与HLA-A*0201之间的亲和性均有不同程度的提高。YIYKRWIIL(259-267Y1),YQANFLGKI(429-437Y1)和YTNNPPIPV(249-257Y1)与HLA-A*0201呈高亲和力结合,荧光系数(flurorescene index,FI)分别为2.68、2.54和2.35,同时肽-HLA-A*0201复合物半数解离时间(dissociation complex50,DC50)均大于8h。预测的低亲和力表位经过修饰可能会成为潜在的HLA-A*0201限制性表位。

The HLA-A*0201 restricted CTL epitopes with low affinity was screened by CTL epitope prediction software based on the super motif and proteasome cleavage probability,and it was favorably modified through amino acid substitution and analyzed by computer. Meanwhile,the affinity and stability between peptides and HLA-A*0201 molecule was determined by using the T2 cell strain and evaluated by means of the stability test. In this way,three candidate CTL epitopes with low affinity were screened. The affinity of t...