HIV-1 gp41 binding proteins and antibodies to gp41 could inhibit enhancement of human Raji cell MHC class I and II expression by gp41.
Based on our findings, that HIV-1 soluble gp41 could bind to several proteins on the human, T, B and monocyte cells independently of CD4, we examined the effect of HIV-1 soluble gp41 (sgp41;Env amino acids 539-684) on surface expression of MHC I and II, ICAM-1 and CD21 molecules on human Raji cells. Flow cytometry (FACS) analysis demonstrated that sgp41 could selectively enhance MHC class I and II expression on Raji cells, but did not increase expression of other cell surface antigens, such as, CD21 and CD54 (ICAM-1). Soluble gp41 could also enhance MHC class I and II expression on another human B cell line, Bjab. The sgp41-dependent enhancement of the MHC class I and II expression on Raji cells is time- and dose-dependent. The sgp41 enhancement effect on the MHC antigen expression could be inhibited by the sgp41-binding proteins of 45, 49 and 62 kD (isolated from Raji-lysate) which could inhibit the spg41-binding to Raji cells. Interestingly, this sgp41-dependent enhancement of the MHC class I and II expression could also be inhibited by two mAbs to HIV-1 gp41, but not by a third mAb binding to a different site on gp41. These results demonstrate that HIV-1 sgp41 can selectively enhance the human Raji cell MHC class I and II antigen expression and this enhancement effect could be inhibited by the sgp41-binding proteins and anti-gp41 antibodies, and suggest that the sgp41-dependent enhancement is mediated by its binding to Raji membrane proteins of 45, 49 and 62 kD.
Chen
Y H
YH
Ludwig-Boltzmann Institute of AIDS Research, Innsbruck, Austria.
Böck
G
G
Vornhagen
R
R
Steindl
F
F
Katinger
H
H
Dierich
M P
MP
D000911:Antibodies, Monoclonal / Q000276:immunology; D002352:Carrier Proteins / Q000276:immunology; D005434:Flow Cytometry; D015483:HIV Antibodies / Q000276:immunology; D015700:HIV Envelope Protein gp41 / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology*; D006681:HLA-D Antigens / Q000096:biosynthesis*; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis*; D006801:Humans; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D002352:Carrier Proteins; D015483:HIV Antibodies; D015700:HIV Envelope Protein gp41; D006681:HLA-D Antigens; D015395:Histocompatibility Antigens Class I