Autologous HIV-1 neutralizing antibodies: emergence of neutralization-resistant escape virus and subsequent development of escape virus neutralizing antibodies.

The capacity of consecutive human sera to neutralize sequentially obtained autologous virus isolates was studied. HIV-1 was isolated three times over a 48-164-week period from three individuals immediately after seroconversion and from two individuals in later stages of infection. Development of neutralizing antibodies to the primary virus isolates was detected 13-45 weeks after seroconversion. Emergence of escape virus with reduced sensitivity to neutralization by autologous sera was demonstrated. The patients subsequently developed neutralizing antibodies against the escape virus but after a delay. Titers of neutralizing antibodies against late virus isolates were generally low compared to initial neutralizing titers against primary virus isolates. The delay in appearance of neutralizing antibodies to the dominant viral strain at any time in the patient and the emergence of neutralization resistant escape virus may be part of the explanation of the apparent failure of the immune system to control HIV infection.