Increased expression of toll-like receptor 2 on monocytes in HIV infection: possible roles in inflammation and viral replication.
BACKGROUND
Toll-like receptors (TLRs) are key pattern-recognition receptors of the innate immune system, but their role in human immunodeficiency virus (HIV) infection is largely unknown.


METHODS
In the present study, we examined the expression of TLR2 and TLR4 on monocytes from 48 HIV-infected patients and 21 healthy control subjects by flow cytometry.


RESULTS
We found that freshly isolated monocytes from HIV-infected patients displayed enhanced expression of TLR2 but not TLR4, that TLR2 expression on the surface of monocytes was significantly increased upon stimulation of HIV type 1 envelope protein gp120, and that TLR2 stimulation in HIV-infected patients induced increased viral replication and TNF- alpha response.


CONCLUSIONS
Our findings suggest potential roles for TLR2 in chronic immune activation and viral replication in HIV infection.
Section of Clinical Immunology and Infectious Diseases, Rikshospitalet University Hospital, N-0027, Oslo, Norway. lars.heggelund@klinmed.uio.no
Lars
L
Heggelund
Fredrik
F
Müller
Egil
E
Lien
Arne
A
Yndestad
Thor
T
Ueland
Knut Ivan
KI
Kristiansen
Terje
T
Espevik
Pål
P
Aukrust
Stig S
SS
Frøland
D000328:Adult; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D016022:Case-Control Studies; D005260:Female; D015699:HIV Envelope Protein gp120 / Q000502:physiology; D015658:HIV Infections / Q000188:drug therapy / Q000276:immunology* / Q000821:virology; D006801:Humans; D066298:In Vitro Techniques; D007249:Inflammation / Q000276:immunology; D016753:Interleukin-10 / Q000096:biosynthesis; D008297:Male; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000502:physiology; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology*; D011956:Receptors, Cell Surface / Q000096:biosynthesis* / Q000502:physiology; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D014779:Virus Replication / Q000276:immunology
D015699:HIV Envelope Protein gp120; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; C495342:TLR2 protein, human; C495345:TLR4 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10