疫苗一直被视为终结人类免疫缺陷病毒1型和2 型(human immunodeficiency virus type 1/2，HIV-1/2)最有力的武器。位于HIV-1 gp41胞外域C末端的近膜端外部区域(membrane-proximal external region, MPER)是一个重要的抗原位点，但糖蛋白41(glycoprotein 41，gp41)在野生型HIV-1的包膜蛋白中并未充分暴露，单独的gp41或MPER多肽无法模拟gp120/gp41包膜蛋白在病毒包膜上的天然状态。本研究以HIV-1 gp41 MPER为抗原进行疫苗设计，以期能诱导产生具有强效中和作用的MPER特异性抗体。通过在gp41的N末端七肽重复域(N-terminal heptad repeat, CHR)和C末端七肽重复域(C-terminal heptad repeat, NHR)引入突变，阻断二者相互作用形成6螺旋(6-helix bundle, 6-HB)构象；使用不同来源的流感病毒HA1亚基替代gp120，以防止机体产生大量针对HA1的抗体，并构建一系列包含不同HA1亚基的HA/gp41-1605嵌合DNA。结果发现，在细胞上表达的嵌合疫苗抗原能更好地展示MPER上的中和表位，但不显示gp41上免疫优势抗原表位。使用构建的HA/gp41嵌合DNA疫苗对新西兰大耳兔进行肌肉内序贯免疫，提示该疫苗策略的确不可诱生高滴度的HA抗体或gp41的loop及6-HB特异性抗体，而能诱生MPER特异性抗体。然而，该抗体对HIV-1不具有中和作用，说明该疫苗策略还有待进一步优化。

Vaccine has long been regarded as the most powerful weapon to HIV, including HIV-1 and HIV-2. The membrane-proximal external region (MPER) located at the C-terminus of the extracellular domain of gp41 is a key antigenic site. However, gp41 is not well-exposed on the wild-type HIV-1 particle, and gp41 molecule or a MPER peptides alone cannot simulate the natural conformation of gp120/gp41 envelope protein on the viral membrane. In this study, we designed a series of chimeric HA/gp41-1605 DNA by introduced mutations in the gp41 NHR and CHR regions to block their interaction to form 6-HB and replacing HA1 using those from different influenza A viruses (IAVs) to prevent the production of a large amount of HA1-specific antibodies and to present the native conformation of the HIV-1 gp41 MPER. The results showed that chimeric vaccine antigens expressed on cells exhibited the neutralizing epitopes in MPER, but did not display the immunodominant antigen epitopes on gp41. After the sequential intramuscular immunization of New Zealand Rabbits with these HA/gp41-1605 chimeric DNA vaccines, we found that the chimeric vaccine could not elicit HA-, loop-, and 6-HB-specific antibodies. Although this vaccine can induce MPER-specific antibodies, but not HIV-1 neutralizing antibodies, suggesting that further optimization of this strategy is warranted.