Complement and antibody mediate enhancement of HIV infection by increasing virus binding and provirus formation.
Previous studies have shown that infection of complement receptor (CR2)-bearing cells with HIV pretreated with antibody (Ab) plus complement (C) resulted in increased virus expression. The current study was designed to determine whether C-mediated 'enhancement' of HIV-1 production was the result of increased virus infection of cells as assessed by provirus formation and virus binding. Virus was incubated with anti-HIV Ab and/or C and added to CR2-positive MT-2 cells. Increased virus expression by MT-2 cells correlated with increased numbers of HIV-immunofluorescent-positive cells at 24 and 48 h and higher levels of provirus detected 8-28 h after infection. MT-2 cells also bound threefold more Ab-plus-C-treated virus than untreated virus. Serial dilutions of C showed that high levels of C with Ab did not enhance but rather suppressed virus expression. Studies were also performed which showed that terminal C components C5 and C8 were not necessary for the enhancing effect. The increased binding of C-coated HIV to CR-positive cells has important implications for the fate of virus in vivo.
June
R A
RA
Rush Presbyterian-St Luke's Medical Center, Chicago, IL 60612.
Schade
S Z
SZ
Bankowski
M J
MJ
Kuhns
M
M
McNamara
A
A
Lint
T F
TF
Landay
A L
AL
Spear
G T
GT
D000944:Antigens, Differentiation, B-Lymphocyte / Q000378:metabolism; D015704:CD4 Antigens / Q000378:metabolism; D002460:Cell Line; D003165:Complement System Proteins / Q000502:physiology*; D015483:HIV Antibodies / Q000502:physiology*; D015497:HIV-1 / Q000276:immunology / Q000502:physiology*; D006801:Humans; D011485:Protein Binding; D011533:Proviruses / Q000502:physiology; D011951:Receptors, Complement / Q000378:metabolism; D017464:Receptors, Complement 3d; D014779:Virus Replication
D000944:Antigens, Differentiation, B-Lymphocyte; D015704:CD4 Antigens; D015483:HIV Antibodies; D011951:Receptors, Complement; D017464:Receptors, Complement 3d; D003165:Complement System Proteins