HIV-Specific Cellular and Humoral Immune Responses in Primary HIV Infection

ABSTRACT Primary human immunodeficiency virus (HIV) infection is characterized by a high-titer viremia that declines precipitously within weeks, most likely as a result of host immune responses. Peripheral blood mononuclear cells (PBMCs) and plasma of four recently HIV-infected individuals were examined to assess the humoral and cellular immune responses potentially involved in early suppression of viral replication. Neutralizing antibodies against autologous viral isolates were low or undetectable in three subjects studied. Cellular cytotoxicity was assayed using Epstein–Barr virus (EBV)-transformed B lymphoblastoid cell lines (B-LCLs) infected with recombinant vaccinia that express HIV-1 proteins. HIV envelope-specific cytotoxicity, which was not mediated by CD8+ cells nor human leukocyte antigen (HLA) class I restricted, developed in PBMCs of all four subjects early after primary infection, but was not correlated with declines in viremia. Gag-specific cytotoxic T lymphocyte (CTL) activity was observed ...