Neutralization profiles of sera from human immunodeficiency virus (HIV)-infected individuals: relationship to HIV viral load and CD4 cell count.

The relationship of the neutralizing activity (NA) profile of sera from human immunodeficiency virus (HIV)-infected individuals to the HN viral load and the absolute CD 1 count was examined. The NA of 24 serum samples against autologous isolates (Al) and HIV type 1 strain MN was examined. Three NA patterns were recognized. Nine sera neutralized both Al and MN (+/+), six sera neutralized RIN but not Al (-/+), and nine sera failed to neutralize both Al and MN (-/-), The identification of the three neutralization patterns (+/+, -/+, and -/-) indicated that resistance to neutralization was progressive. A reciprocal relationship between the viral burden of the patients and the NA profiles was observed. The nine subjects with a -/- NA profile had a plasma viral load of greater than or equal to 5 x 10(4) copies/ml and a cellular viral burden of greater than or equal to 1,122 infectious units per million viable cells, which were significantly different from those of the other groups (P < 0,02), These patterns were independent of the phenotypic characteristics of the virus. Longitudinally, subjects with a -/- profile at baseline gained their HIV-specific NA by 24 weeks of antiretroviral therapy when this was associated with a greater than or equal to 1-log(10) decline in the plasma HIV viral load. The sera from week 24 from some patients were able to neutralize both the 24-week and the baseline dominant virus isolates. A change in CD4 cell count of 50 or more in either direction predicted a -/- or +/+ profile. The verification of the autologous NA profile might be important in selecting patients who may benefit from immune based therapies involving neutralizing monoclonal antibodies.