HIV-1 Tat is an important regulatory protein involved in AIDS pathogenesis.However, the immunoprofiles of anti-Tat responses remain unclear.We analysed the immunoprofiles of the anti-Tat antibody responses and the neutralizing activities.Out of 326 HIV-1-seropositive individuals, 12.9％ were positive for anti-Tat antibodies.We found six different immunological profiles of anti-Tat antibody responses: full-potential response, combined response, N-specific response, C-specific response, full-length Tat-specific response and Tat-related response.These responses represent two types of anti-Tat responses: the major complete response and the alternative Cprone response.A Tat-neutralizing activity is significantly higher in anti-Tat-seropositive samples than anti-Tatnegative or healthy blood-donor samples, and significantly correlates with the anti-Tat reactivities.The data here could contribute to a better understanding of the significance of anti-Tat responses in preventing HIV pathogenesis and could be useful for designing more effective vaccines in the future.