The present invention relates to a method for reducing the occurrence and/or severity of viral infections. The method embodies procedures for expanding HIV from the blood of HIV antibody negative donors and deriving a non-infectious virus particle product that is antigenic. The procedures for deriving the antigenic, non-infectious virus particle product are optimally designed to maintain the integrity of the envelope proteins while maximizing the depletion of capsid proteins and RNA. The resulting virus particle product, when introduced into humans or non-human animals, enables the production of antibodies that target the natural envelope macromolecular structure that is required for infectivity. The present invention can be applied to producing virus stocks from the blood of HIV-seronegative donors, for deriving non-infectious virus particles that retain intact envelope proteins, for producing anti-viral antibodies, and for administering anti-virus antibodies to patients.
