Antibodies against synthetic peptides of herpes simplex virus type 1 glycoprotein D and their capability to neutralize viral infectivity in vitro.

Peptides corresponding to residues 1-13, 9-21, 18-30, 82-93, 137-150, 181-197, 232-243, 235-243, 267-281, 271-281 and 302-315 of glycoprotein D of herpes simplex virus type 1 (HSV-1) were chemically synthesized. These peptides were coupled to carrier proteins, and the resulting conjugates were used to immunize rabbits. An enzyme-linked immunosorbent assay was used to determine antipeptide antibody titers in serum collected after immunization. All peptides appeared to be immunogenic in rabbits. Western immunoblot analysis with detergent extracts of HSV-1-infected Vero cells showed that antibodies against each of the peptides were able to react with the parent glycoprotein under denaturing conditions. Antisera against peptides 1-13, 9-21, and 18-30 neutralized HSV-1 infectivity in vitro, peptide 9-21 being the most successful in this respect. Immunization with a mixture of peptides 9-21 and 267-281 yielded antisera which reacted strongly with glycoprotein gD in Western blot analysis and showed a more solid virus-neutralizing activity in vitro.

Purification strategies for Sendai virus membrane proteins.

Viral membrane proteins extracted from Sendai virions with the non-ionic detergents decylpolyethyleneglycol-300 and Triton X-100 were used as a model mixture of hydrophobic membrane proteins. The detergent extract contained the fusion protein (F) and the tetrameric and dimeric forms of the hemagglutinin-neuraminidase protein (HN). These proteins were purified by size-exclusion high-performance liquid chromatography (HPLC) in the presence of 0.1% sodium dodecyl sulphate, by ion-exchange and metal chelate affinity HPLC in the presence of 0.1% decylpolyethyleneglycol, and by reversed-phase HPLC without prior removal of the detergent. The tetramer of HN and F could be purified by size-exclusion HPLC after dissociation of a micellar aggregate containing tetrameric HN and multimeric F. The F and HN proteins could be purified by ion-exchange HPLC. Pure F protein could be obtained after metal chelate affinity HPLC. The F protein and the dimer and tetramer of HN could be eluted from a large-pore (100 nm) reversed-phase column, but they were eluted as broad, overlapping peaks. Only after reduction of the virion extract, the relatively small (13-15 kilodaltons) F2 protein could be obtained in pure form.

Size-exclusion high-performance liquid chromatography of Sendai virus membrane proteins in different detergents. A comparison of different columns.

Four column packings for size-exclusion high-performance liquid chromatography (HPLC) of proteins with particle sizes from 3 to 13 micron were compared, using 0.1% sodium dodecyl sulphate in the solvent. Their suitability for the purification of hydrophobic membrane proteins was studied with Sendai virus proteins as a model. The calibration curves of the two 13-micron column packings were linear up to high molecular weights. In contrast to this, large proteins (greater than 100-150 kD) were eluted later than expected from the 3- and 6-micron packings. Peak capacities for proteins larger than 20 kD ranged from 4.7 to 5.5. Therefore, purification of complex mixtures of membrane proteins will often require rechromatography by a different mode of HPLC. Non-ionic detergents are suitable for further ion-exchange chromatography. The effect of addition of 0.1% of five non-ionic detergents (three gluco-methylalkanamide detergents, octylglucoside, and decyl-polyethyleneglycol-300) to the solvent was investigated and decyl-polyethyleneglycol-300 was found to be most suitable. Size-exclusion HPLC with this detergent resulted in the separation of micelles of three different sizes, of which the larger two contained exclusively the Sendai virus F protein.

Combined size-exclusion and reversed-phase high-performance liquid chromatography of a detergent extract of Sendai virus.

Virus envelope proteins obtained by Triton X-100 extraction of Sendai virions were purified to a high degree by a combination of high-performance liquid chromatography (HPLC) methods. Size-exclusion HPLC on a TSK 4000 PW column with several concentrations of acetonitrile or ethanol-1-butanol in 0.1% hydrochloric acid as eluent was used as the first chromatographic step. Peak fractions were diluted in water and further fractionated on reversed-phase columns (TMS-250 or Vydac 218 TP). Size-exclusion HPLC with 45% acetonitrile in 0.1% hydrochloric acid, combined with reversed-phase HPLC on either column, was most suitable for obtaining highly purified F2 protein. Antibodies obtained after injection of this protein were reactive with the intact virus.