Sequence evolution and cross-reactive antibody responses to hypervariable region 1 in acute hepatitis C virus infection

Hepatitis C virus (HCV) infection may result in acute resolving or chronic infection. Patients that clear the infection have a more vigorous cellular immune response and an early humoral response to the hypervariable region 1 (HVR1) of the E2 envelope protein. To analyse further the properties of th e early anti-HVR1 response, crossreactivity of anti-HVR1 responses was asse ssed in five patients with acute HCV infection, who were infected by the sa me virus strain during a nosocomial outbreak. The sequence evolution of HVR 1 was examined in sequential serum samples up to 37 months post infection. Peptides were synthesised corresponding to the obtained HVR1 sequences and unrelated HVR1 sequences, and antibody reactivity to the peptides in sequen tial sera was investigated by ELISA, The results suggest an association bet ween specific gaps in humoral immunity and the HVR1 sequence evolution duri ng early infection. Possible interpretations of this phenomenon include imm une escape mechanisms or suppression of specific anti-HVR1 antibodies. (C) 2001 Wiley-Liss. Inc.