Document 0671
 DOCN  M9550671
 TI    Efficacy of HIV-specific and 'antibody-independent' mechanisms for
       complement activation by HIV-infected cells.
 DT    9505
 AU    Saarloos MN; Lint TF; Spear GT; Department of Immunology/Microbiology,
       Rush Medical School,; Chicago, IL 60612.
 SO    Clin Exp Immunol. 1995 Feb;99(2):189-95. Unique Identifier : AIDSLINE
       MED/95153900
 AB    Previous studies in this laboratory have shown that efficient activation
       of complement (C) on HIV isolates and HIV-infected cells requires the
       binding of specific anti-HIV antibodies, while other investigators have
       observed 'antibody-independent' C activation. In an attempt to clarify
       these disparate findings, we investigated the effect of several
       variables on C activation by HIV-infected cells using flow cytometric
       analysis of C3 deposition. Antibody-mediated C activation using pooled
       sera from infected persons or human MoAbs directed against the V3 region
       of gp120 was always substantially higher than activation without
       antibody. Normal human serum (NHS) from a subset of HIV
       antibody-negative donors did, however, induce low levels of C3
       deposition. Differences in C3 activation between the various NHS did not
       correlate with total haemolytic C levels or mannose-binding protein
       (MBP) levels. IgM isolated from NHS that induced high levels of C
       activation was at least partly responsible for the
       'antibody-independent' C activation. Although there appeared to be a
       correlation between NHS that induced C activation and the presence of
       anti-blood type B IgM, absorption of anti-B did not abrogate the C3
       deposition. Additionally, MoAb to the B antigen did not induce C3
       deposition. These studies show that IgM in sera from HIV-uninfected
       donors can induce C3 deposition on HIV-infected cells, but that specific
       antibody-dependent C activation is substantially more efficient.
       Therefore, 'antibody-independent' C activation on HIV-infected cells
       may, in some cases, be more accurately described as HIV-cross-reactive
       antibody-dependent C activation.
 DE    Antibody Specificity  ABO Blood-Group System/IMMUNOLOGY  Cell Line
       Complement Activation/*IMMUNOLOGY  Complement Hemolytic Activity
       Assay/METHODS  Complement 3/IMMUNOLOGY  Cross Reactions/IMMUNOLOGY  Flow
       Cytometry  Human  HIV Antibodies/*IMMUNOLOGY  HIV-1/*IMMUNOLOGY
       IgM/IMMUNOLOGY  Support, U.S. Gov't, P.H.S.  JOURNAL ARTICLE

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