CD4 and HIV-1 infection: However, addition of the purified lectin domain even up to a concentration of 200 μg/ml was not sufficient to measurably inhibit HIV-1 infection in human CD4+ T-lymphocytic C8166 cell and Raji DCSIGN cultures under our experimental conditions where HHA and GRFT were clearly inhibitory at concentrations less than 1 μg/ml (data not shown).