Abstract: Objective To investigate the effect of semen-derived enhancer of virus infection (SEVI) on the infection of transmitted/founder (TF) HIV-1 and its matched chronic control (CC) viruses and the antagonism of ADS-J1 on SEVI-mediated enhancement of TF and CC virus infection in vitro. Methods PAP248-286 self-assembling into SEVI amyloid fibrils was validated by ThT assay. We generated the virus stocks of TF and CC virus pair. TZM-bl cells were infected with the mixture of SEVI and TF or CC viruses for 72 h. Luciferase activity was used to observe the enhancement of SEVI. SEVI was treated with different concentrations of ADS-J1 and incubated with TF or CC viruses. TZM-bl cells were then infected with the mixture and luciferase activity was detected 72 h after infection to analyze the antagonism of ADS-J1 on the enhancing effect of SEVI. ADS-J1 was also incubated with TF and CC viruses directly and TZM-bl cells were infected for 72 h to evaluate the antiviral effect using luciferase assay. SEVI was treated with ADS-J1 and Zeta potential was determined to explore the antagonistic mechanism of ADS-J1. Results ThT assay showed that PAP248-286 was capable of self-assembly into SEVI amyloid fibrils. SEVI significantly accelerated TF and CC viruses infection (P<0.05), and ADS-J1 not only significantly antagonized the enhancement of SEVI (P<0.05) but also directly inhibited the infection of TF and CC viruses (P<0.05). ADS-J1 neutralized the positive charge of SEVI in a dose-dependent manner. Conclusions SEVI promotes the infection of TF and CC strains, and ADS-J1 antagonizes SEVI-mediated enhancement of TF and CC viruses by neutralizing the positive charge of SEVI.