Monoclonal antibodies define linear and conformational epitopes of HIV-1 pol gene products.

Purified recombinant reverse transcriptase (RT) from human immunodeficiency virus type 1 (HIV-1) was used to raise 21 monoclonal antibodies with anti-RT specificities. The antibodies were characterized using Western blotting against native virus and recognized either the p66 or p66, p51 components of RT. Further immunoblotting using either cyanogen bromide fragmented RT or truncated mutants of RT along with cross-competition studies enabled the location of various immunogenic regions of RT to be identified. Three antibodies recognized a linear epitope in the N-terminal region (amino acids 128-176). Also, a neutralizing RT antibody recognized a conformational epitope in this region. Three monoclonals had epitopes mapped to linear sequences in the RNase H region at the C-terminus of the RT. Another neutralizing antibody, also requiring folding of the RT protein had its epitope more centrally located (231-353). Of the remaining 13 monoclonals, 7 were roughly located in the C-terminal region and required folding of the protein for epitope recognition and only three of the remaining six could be mapped to conformational epitopes in N-terminal and central regions of the RT. None of the antibodies tested recognized HIV-2 RT products p68 and p55 in Western blot.