Document 0862
 DOCN  M9480862
 TI    p24 Antigen is not primarily virion-associated in peripheral blood of
       HIV-infected individuals: a comparison with quantitation of HIV RNA.
 DT    9410
 AU    Wilber J; Yeghiazarian T; Todd J; Urdea M; Chiron Corporation,
       Emeryville, CA.
 SO    Abstr Gen Meet Am Soc Microbiol. 1994;94:483 (abstract no. T-8). Unique
       Identifier : AIDSLINE ASM94/94313083
 AB    The level of p24 antigen has been used as a surrogate marker for the
       level of viremia in HIV-infected patients. To understand the extent to
       which p24 antigen (p24Ag) is associated with virions, EDTA plasma was
       collected from 12 HIV-infected individuals and assayed for the quantity
       of virion-associated HIV p24Ag and RNA. Since there are numerous
       published observations that free RNA is highly unstable in plasma, it
       was assumed that detectable HIV RNA was contained in virions. Samples
       were tested for HIV RNA using branched DNA signal amplification
       (Quantiplex HIV-RNA, Chiron Corporation, Emeryville, California) and for
       p24Ag using the immune complex-dissociation (ICD) modification of the
       p24Ag Assay (Coulter Corporation, Hialeah, Florida). Virions were
       separated from two 1 ml aliquots of each plasma sample by centrifugation
       at 23,000 g at 2-8 C for 1 hr. RNA and p24 Ag were measured in whole
       plasma and supernatant, and RNA was measured in reconstituted pellets.
       As shown in Figure 1, a mean of 85% of p24Ag remained in the supernatant
       after virions were pelleted. The ratio of virion-associated to free
       p24Ag varied from patient to patient. These results may help explain
       previously reported inconsistencies between infectious virus titer and
       p24Ag quantitation. The source of non-virion-associated p24Ag could be
       degraded virus or whole virus-independent production of antigen.
       Variation in p24Ag levels could be due to strain-dependent differences
       in these processes and not to changes in virus load, which may lead to
       problems in interpretation. TABULAR DATA, SEE ABSTRACT VOLUME.
 DE    Gene Amplification  Human  HIV/*ISOLATION & PURIF/PHYSIOLOGY  HIV
       Antigens/BLOOD  HIV Core Protein p24/*BLOOD  HIV Infections/*BLOOD  RNA,
       Viral/ANALYSIS/GENETICS  Virion/*ISOLATION & PURIF/PHYSIOLOGY  MEETING
       ABSTRACT

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).