Study on the relationships between neutralizing antibody response against heterologous virus and disease progression of HIV type 1 B'/C infected individuals in China
Objective To study the relationships between neutralizing antibody response against heterologous virus and disease progression in Chinese HIV-1 B'/C infected individuals. Methods Plasmas from HIV-1-infected individuals, grouped as HIV chronically infected or AIDS according to CD4+ count and clinical symptom, were tested for neutralizing activity against the three HIV-1 isolates with very low homology in vitro. Six two-fold dilutions of each plasma sample (from 1/10 to 1/320) were tested against each virus from the panel. Giving a 50% reduction in p24Ag compared with normal human plasma control wells was defined as positive. The breadth of the cross-neutralizing response was defined based on the number of viruses that were effectively neutralized by any given patient-derived plasma sample. The magnitude of the crossneutralizing response was defined based on the average neutralizing titer against all heterologous viruses. Resuits We found that there revealed a significant difference between HIV chronically infected and AIDS group in the breaths and magnitudes of neutralizing heterologous virus. There was higher prevalence for the frequency of neutralizing heterologous virus in HIV chronically infected than AIDS. The results showed that there was positive correlation between the breadths and magnitudes of neutralizing response against heterologous virus and the plasma HIV RNA level in HIV chronically infected group, while not in AIDS group. There was no association between the breadth of the neutralizing responses against heterologous virus and CD4 T cell counts. Conclusion The capacity of neutralizing antibodies against heterologous virus varied among different disease stage. There were higher titers of neutralizing antibodies in HIV chronically infected than AIDS group. The loss of neutralizing antibodies in plasma from AIDS group appears to be associated with a narrowing of the antibody response during disease progression. These suggest that the presence of neutralizing antibodies against hetreologous virus was associated with disease progression. 
 
Key words: 
HIV-1;  B'/C subtype;  Neutralizing antibodies;  Heterologous virus