A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide microplate assay was adapted to screen for the ability of 20 host-defense peptides to inactivate herpes simplex virus type 1 and type 2. The procedure required minimal amounts of material, was reproducible, and was confirmed with standard antiviral testing techniques. In screening tests, with the exception of melittin, a highly cytotoxic and hemolytic peptide found in bee venom, the alpha-helical peptides in our test panel (magainins, cecropins, clavanins, and LL-37) caused little viral inactivation. Several beta-sheet peptides (defensins, tachyplesin, and protegrins) inactivated one or both viruses, sometimes with remarkable selectivity. Two peptides were identified as having antiviral activity against both viruses, indolicidin (a tryptophan-rich peptide from bovine neutrophils) and brevinin-1 (a peptide found in frog skin). The antiviral activity of these two peptides was confirmed with standard antiviral assays. Interestingly, the antiviral activity of brevinin-1 was maintained after reduction and carboxamidomethylation, procedures that abolished its otherwise prominent hemolytic and cytotoxic effects.

We identified a novel heterodimeric protein, lipophilin AC, in human tears. One of its components, lipophilin A (69 residues; mass, 7575.1; pI, 9.47) was homologous to the C1 and C2 components of prostatein (`estramustine-binding protein'), the major secreted protein of rat prostate. Human lipophilin C (77 residues; mass, 8854.1; pI, 4.94) was homologous to the rat prostatein C3 component and to human mammaglobin, a protein overexpressed in some mammary carcinomas. Tear lipophilins A and C expand the roster of human uteroglobin superfamily members and provide models for exploring these typically steroid-regulated and steroid-binding molecules.z 1998 Federation of European Biochemical Societies.

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Both full-length and subgenomic negative-strand RNAs are initiated at the 3' terminus of the positive-strand genomic RNA of the arterivirus, simian hemorrhagic fever virus (SHFV). The SHFV 3'(+) non-coding region (NCR) is 76 nts in length and forms a stem loop (SL) structure that was confirmed by ribonuclease structure probing. Two cell proteins, p56 and p42, bound specifically to a probe consisting of the SHFV 3'(+)NCR RNA. The 3'(+)NCR RNAs of two additional members of the arterivirus genus specifically interacted with two cell proteins of the same size. p56 was identified as polypyrimidine tract-binding protein (PTB) and p42 was identified as fructose bisphosphate aldolase A. PTB binding sites were mapped to a terminal loop and to a bulged region of the SHFV 3'SL structure. Deletion of either of the PTB binding sites in the viral RNA significantly reduced PTB binding activity, suggesting that both sites are required for efficient binding of this protein. Changes in the top portion of the SHFV 3'SL structure eliminated aldolase binding, suggesting that the binding site for this protein is located near the top of the SL. These cell proteins may play roles in regulating the functions of the genomic 3' NCR.

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