HIV-1拉米夫定(3TC)耐药毒株的体外诱导培育和鉴定

Cultivation and identification of 3TC-resistant HIV-1 strain

目的通过体外传代培养,将我国HIV1药物敏感毒株诱导为拉米夫定耐药毒株。方法在MT4细胞中国HIV1B′亚型CNHN24毒株培养系统中加入0.008μmolL拉米夫定,逐渐增加药物浓度进行传代和培养,每隔3～5代测定半数抑制浓度(IC50),并用RTPCR法扩增pol区基因,进行基因型耐药性分析。将表型和基因型耐药结果与敏感株进行比较。结果培养6代后,IC50由野生毒株的0.018μmolL逐渐提高到0.15μmolL;第7代时,IC50突然增加到大于2048μmolL;pol区的184位氨基酸由甲硫氨酸(M)突变为异亮氨酸(I)。去除药物继续培养5代,IC50仍维持>2048μmolL,pol区184位氨基酸仍为异亮氨酸,没有发生回复突变。结论在国内首次用中国HIV1毒株诱导培育出可能稳定传代的3TC耐药株,可用于HIV1耐药性的研究和HIV1药物的药效学评价。该耐药株已申请国家专利。

Objective To gain stable 3TC-resistant HIV-1 strain originated from Chinese HIV-1 B＇ strain. Methods HIV-1 B＇ strain isolated from Henan province, China was cultured and passaged with the medium containing double increased 3TC. by 3-5 generations of passage, the 50% inhibitory concentrations of cultures （IC50） were tested. The partial HIV-1 pol gene were amplified and sequenced, the sequence were interpreted with genotypic drug resistance result by the tool from Stanford. Results After 6 generation of passage, the IC50 to 3TC had increased 8.3-fold from 0.008μmol/L to 0.15μmol/L. In the 7^th generation, the IC50 dramatically increased to more than 110 000-fold（2048 μmol/L）, genotypic analysis showed that a significant mutation had happened in the position of 184（Met→Ile） of pol gene, the genotype and phenotype of 3TC resistance remained stable after the 5^th generation of cultivation in the absence of drug. Conclsion A rather stable 3TC-resistant variant was established from HIV-CNHN24. This strain can be used for the assessment of the new drug effect and the research of HIV-1 drug resistance.