Cell surface proteins binding to recombinant soluble HIV-1 and HIV-2 transmembrane proteins.
OBJECTIVE
To further characterize cell surface proteins binding to recombinant soluble (rs) forms of the transmembrane glycoproteins gp41 of HIV-1 (rsgp41) and gp36 of HIV-2 (rsgp36).


METHODS
Various human and murine cell lines of different lineages were surface-labelled with 125I. rsgp41 and rsgp36 were bound to CnBr-Sepharose and used as an affinity matrix for the surface-labelled cell lysates. The bound cell surface proteins were separated on sodium dodecyl sulphate polyacrylamide gel electrophoresis under reducing conditions. A rabbit serum was produced against one of the cell surface proteins and flow cytometry used to compare the results with those obtained from affinity chromatography.


RESULTS
We have confirmed and extended the results obtained by Qureshi et al. [1]. In addition to the 44kD protein, we identified cell surface proteins with molecular weights of 98 and 106 kD binding with high affinity to both rsgp41 and rsgp36. We have demonstrated differences between human and murine cell lines in the expression of the cell surface proteins that interact with rsgp41 and rsgp36. Furthermore, a correlation between the level of rsgp41 and rsgp36 binding proteins, detected either by affinity chromatography or by reactivity with an antiserum directed against one of the cell surface binding components was shown.


CONCLUSIONS
Three cell surface proteins, with molecular weights of 44, 98 and 106 kD, bind with high affinity to rs forms of gp41 and gp36. Their expression decreases from a T-lymphoid cell line, to a monoblastoid cell line, to a cell line representing mature monocytes. Human T-cell lymphotropic virus-infected cell lines show a predominance of the 44 kD protein. There are species-specific differences, in that murine cell lines lack the 44 kD protein.
Institut für Hygiene, Leopold Franzens Universität, Innsbruck, Austria.
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Ebenbichler
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Röder
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Vornhagen
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Ratner
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Dierich
D000818:Animals; D002460:Cell Line; D015686:Gene Products, env / Q000378:metabolism*; D015488:HIV Antigens / Q000378:metabolism*; D015700:HIV Envelope Protein gp41 / Q000378:metabolism*; D015497:HIV-1 / Q000378:metabolism*; D015498:HIV-2 / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D051379:Mice; D008970:Molecular Weight; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism; D012995:Solubility; D013045:Species Specificity; D054299:env Gene Products, Human Immunodeficiency Virus
D015686:Gene Products, env; D015488:HIV Antigens; D015700:HIV Envelope Protein gp41; D008565:Membrane Proteins; D011994:Recombinant Proteins; D054299:env Gene Products, Human Immunodeficiency Virus; C059763:env protein gp36, Human immunodeficiency virus