Evidence for an antiviral effect and interferon neutralizing capacity in human sera; variability and implications for HIV infection.

The antiviral effect (AVE) and interferon neutralizing capacity (INC) of sera originating from either seronegative or HIV-infected individuals were determined. As a rule, sera from seropositive subjects exhibited higher AVE titers than sera from seronegative individuals. Similarly, the INC of sera from HIV-infected patients, was most often stronger than that of sera from seronegative individuals. Furthermore, sera from HIV-infected patients actively immunized with i-IFN alpha invariably expressed INC in response to treatment, which was not the case for sera from control unimmunized patients. All sera from HIV-infected patients were found by ELISA to contain antibodies specifically directed to IFN alpha.