The HIV-1 Nef protein shares an antigenic determinant with a T-cell surface protein.

OBJECTIVE

To characterize antigens on uninfected T lymphocytes reactive with monoclonal antibodies (MAb) directed against the HIV-1 Nef protein, and to search for antibodies directed against this epitope in HIV-1-infected individuals.

DESIGN

Murine MAb directed against an epitope of Nef defined by amino acids 60-73 reacted with cell surface antigens of normal peripheral blood lymphocytes and permanent human T-cell lines.

METHODS

The specificity of the MAb reaction was investigated by flow cytometry and immunofluorescence. The antigen was precipitated from lysates or uninfected cells using MAb or sera from HIV-1-infected individuals and analysed by Western blot and isoelectrofocusing.

RESULTS

An antigen with an apparent relative molecular mass of 137,000 and an isoelectric point of 8.45 was immunoprecipitated with the cross-reactive MAb from uninfected human T cells. Sera from HIV-positive individuals recognizing a Nef epitope partially overlapping with the binding site of the cross-reactive MAb stained the 137 kD protein precipitated with the MAb in Western blot analysis, while HIV-positive sera without antibodies to this Nef region and sera from uninfected individuals were negative.

CONCLUSION

The induction of autoantibodies cross-reactive with cellular surface proteins may play a role in the pathogenesis of AIDS.