Polyclonal antiserum to an Escherichia coli-produced beta-galactosidase/E4 fusion protein of human papillomavirus type 6b (antiserum 256), and affinity purified HPV 11 anti-E4 antibodies were tested for reactivity in Western blots with bacterially expressed trpE/E4 fusion proteins of HPV types 6b, 11, 16, and 18. To further characterize the affinity purified anti-E4 antibodies, a dot-immunobinding assay was performed using overlapping synthetic HPV 11 E1-E4 peptides as antigens. Protein extracts of condylomata acuminatum from 18 patients containing HPV type 6 of 11 DNA sequences were tested in Western blots using antiserum 256 or affinity purified HPV 11 anti-E4 antibodies. In the western blots of the trpE proteins, antiserum 256 identified the HPV types 6b and 11 fusion proteins; the affinity purified HPV 11 anti-E4 antibodies identified only the HPV 11 fusion period. In the dot-immunobinding assay, three HPV 11 peptides were recognized, each containing a shared 8 amino acid sequence that differs significantly from the corresponding sequences of HPV types 6b, 16, or 18. In the Western blots of protein extracts from 18 condylomata acuminatum samples shown to contain HPV types 6 or 11 DNA, putative E4 gene products were identified in six samples by antiserum 256. The affinity purified HPV 11 anti-E4 antibodies identified putative E4 gene products in one of these same six lesions, which was shown to contain HPV 11 sequences by the Southern blot method. All six samples containing E4 gene products were from women. Three of these women were pregnant, one had serum antibodies to the human immunodeficiency virus, and one was a renal transplant recipient receiving glucocorticoids. This study suggests that unique antigenic sites exist in E4 gene products of HPV types 6 and 11 that distinguish them from other HPV types. Antisera to bacterially expressed E4 fusion proteins can detect putative E4 gene products of HPV types 6 and 11 in condylomata acuminatum from certain patients infected with these HPV types. It may be possible to produce reagents that will detect HPV E4 gene products in a type specific manner in those tissues where these proteins are expressed. These reagents should be useful in determining the conditions leading to E4 gene expression.
- Antibodies against bacterially expressed fusion proteins
- Condylomata acuminatum
- E4 protein
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