Thirteen peptides corresponding to amino acid sequences predicted from the nucleotide sequence ofthe hepatitis B surface antigen were synthesized chemically. The free or carrier-linked synthetic peptides were injected into rabbits, and 7 of the 13 elicited an antipeptide response. Antisera against four of the six soluble peptides longer than 10 amino acids were reactive with native antigen and specifically precipitated the 23,000-and 28,000-dalton forms from Dane particles. As the hepatitis molecule had not been chosen for study because of any structural feature suggesting unique opportunities for success, these results suggest that the strategy is general and should work for any protein as long as enough domains are studied. Peptides such as these could prove to be ideal vaccines. The cloning and sequence determination of genes have greatly increased our knowledge of the structure of proteins and suggested mechanisms by which some are synthesized, processed, and transported. As we move to the study of uncharted genetic regions, however, we encounter a gap between the ease with which a gene can be cloned and sequenced and the unequivocal assignment of its protein product. Recently, a solution to this problem was offered that demonstrated that one could produce antibodies to a few chemically synthesized peptides predicted from newly solved nucleotide sequences and then use these antibodies to define the protein product ofthe gene in question (1-3). The most important feature ofantibodies made in this way is that they are directed against a small region of the protein, determined in advance by the investigator, and are thus unique biochemical reagents. Because this technology could have significant implications, it was important to learn whether the somewhat limited experience could be generalized and any "rules" that might be derived concerning which regions of proteins offered the best possibilities for selection ofpeptides likely to yield useful antibodies. We selected as models two genes whose nucleotide sequences were known and whose protein products were of both theoretical and practical interest. The first was the major envelope protein of the hepatitis B genome, a molecule that, because of its extreme hydrophobicity, offered an interesting challenge to the technology. The second was the hemagglutinin of influenza virus because its complete crystallographic structure is known (4); thus, one could correlate how antibodies to protein domains ofknown molecular location perturb virus infectivity and, in fact, what the structural correlates ofantigenicity are for the molecule. We report here our studies on the hepatitis B surface antigen (HBsAg).HBsAg is a glycosylated protein and the major surface antigen of the 42-nm particles (Dane particle) of hepatitis B virus (5-7). The HBsAg contains group-and type-specific determinants and is thought to be the major target of neutralizing antibody (6). Purified preparations of HBsAg are physically heterogenous and consist of at least seven polypeptides ranging i...
We previously determined the nucleotide sequence of the 3' end of Moloney leukaemia virus and discovered the potential coding region for an unknown protein, R. We now show that this region does encode a protein. A pentadecapeptide of R was chemically synthesized and antibodies raised against it. Antisera to the synthetic peptide recognize the R protein and the env precursor polyprotein in infected cells. The strategy presented here should provide a general method for accessing proteins predicted by nucleotide sequences.
It is possible to regulate the activity of human influenza virus specific helper T-cell clones either by high concentrations of antigen or by anti-idiotypic suppressor T cells. In the absence of accessory cells, the appropriate peptide antigen recognized by the clones induces specific unresponsiveness. This phenomenon, however, is not the result of cytolysis as responsiveness to IL-2 remained unaltered. This suggests that high-dose immunological tolerance need not involve suppressor T cells, and that peptide antigens can interact directly with the T-cell surface. As recent reports suggest that the T-cell surface antigen T3 is involved in the triggering of T lymphocytes and possibly in antigen recognition we have investigated the expression of T3 and other cell surface antigens following the induction of T-cell tolerance. We report here that when a T-cell clone is exposed to a tolerizing concentration of the appropriate peptide antigen, surface T3 antigen is lost in a dose-dependent manner. As loss of surface T3 induced by anti-T3 antibody also results in unresponsiveness to antigen, we conclude that T3 is involved in the process of T-cell triggering by antigen.
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