Journal of General Virology, Vol 79, 2883-2894, Copyright © 1998 by Society for General Microbiology
Selection of human anti-human immunodeficiency virus type 1 envelope single-chain antibodies from a peripheral blood cell-based phage repertoire
JJ de Haard, B Kazemier, P Oudshoorn, P Boender, B van Gemen, MJ Koolen, G van der Groen, HR Hoogenboom and JW Arends
Biosciences Research Unit, Organon Teknika, Boxtel, The Netherlands.
Monoclonal antibodies play an important role in the development of
diagnostic assays. Instead of using hybridoma technology to isolate human
immunodeficiency virus type 1-specific antibodies, a phage- displayed
antibody library was generated from a small number (10(7)) of peripheral
blood lymphocytes from a seropositive donor. Two families of single-chain
antibodies (scFvs) were selected by biopanning with the envelope precursor
gp160. ELISA and competition in the BIAcore system revealed that one
antibody family recognized a conformation-sensitive epitope within gp120,
while the other antibody family was gp41- specific. The latter group had
sequence similarity to antibodies recognizing the cluster III epitope of
gp41. Binding of scFvs to gp160 could be inhibited with the donor's serum
antibodies, indicating that antibodies with a similar specificity were
circulating in the donor's blood. Competition experiments suggested that
the epitope of the anti- gp41 antibodies was recognized by a broad range of
patients' sera: 21 out of 22 sera from North American and all 20 sera from
African seropositive patients inhibited binding of scFvs. In contrast,
three sera from this panel did not react with the epitope of the anti-gp120
antibodies. These data indicate that, because of the conserved nature of
its epitope, the anti-gp41 antibody will be suitable for diagnostic
applications.
