The development of chemically synthesized vaccines.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
F Brown
Publications and source records attributed to F Brown.
Host cell selection of antigenic variants of foot-and-mouth disease virus.
Foot-and-mouth disease virus (FMDV) A22 Iraq 24/64 adapted to grow in BHK monolayer cells induced antibodies which neutralized many isolates belonging to the A serotype. Plaque-purified virus isolated from this stock also induced broadly reactive antibodies, showing that this property is not due to the combined response to a mixture of variants in the original stock virus. However, viruses obtained by passage in suspension BHK cells of either the monolayer cell-adapted virus or a virus cloned from this stock resulted in the selection of virus which induced antibodies with highly specific neutralizing activity. In addition to their antigenic properties the monolayer and suspension cell-adapted viruses could be distinguished by plaque morphology, tendency to aggregate and ability to attach to BHK cells. Monoclonal antibodies (MAbs) induced with the plaque-purified monolayer-adapted virus had neutralizing activity almost as broad as polyclonal serum, showing that this property can be represented by a single epitope on the virus. These neutralizing MAbs recognize a trypsin-sensitive epitope on the virus. Surprisingly, sequence analysis of the structural protein-coding regions of the genomic RNAs of monolayer and suspension cell-adapted viruses showed no amino acid differences in VP1, the protein known to contain the major neutralization epitope in FMDV and to be the only protein susceptible to cleavage by trypsin in the virus particle. Although three coding differences were found in the capsid protein these were all located in VP2.
Amino Acid Sequence↗
Epitope mapping of foot-and-mouth disease virus with neutralizing monoclonal antibodies.
Epitopes of strain A22 Iraq 24/64 of foot-and-mouth disease virus have been mapped with monoclonal antibodies (MAbs). Three methods were used: (i) an indirect ELISA using an overlapping set of peptides, (ii) production of neutralization escape variants against each MAb and (iii) sequencing of neutralization escape variants. The study has shown that the virus has at least three overlapping liner neutralizing epitopes within a major antigenic site on VP1. The presence of a second, conformational site was demonstrated but its position on the virus particle was not located. Synthetic peptides with sequences representing the major site elicit antibodies which have similar broad cross-neutralizing activity to polyclonal serum or neutralizing MAbs produced with the virus against a range of field isolates.
Amino Acid Sequence↗
Serological prospects for peptide vaccines against foot-and-mouth disease virus.
Antibodies to a synthetic peptide corresponding to the 141 to 160 amino acid sequence of the protein VP1 of type O foot-and-mouth disease virus (FMDV) neutralize a wider range of type O isolates than anti-virion serum. Extending this peptide at the amino terminus reduced the number of strains neutralized by the antipeptide sera. Reactions with antisera to peptides representing non-contiguous native sequences showed that it was also possible to increase the number of strains effectively neutralized. Selected substitutions of a single amino acid at position 148 markedly altered the neutralizing specificity of antibodies elicited by the 141 to 160 peptide. In particular, a peptide with an L----S substitution at this position induced antibodies which neutralized a type O and a type A virus equally, and guinea-pigs inoculated with it were protected from challenge with either virus. Attempts to isolate variant viruses resistant to neutralization with anti-peptide antibody indicated that these occurred at low frequency, and there was some evidence that resistance may be partially conferred by mutations outside the peptide sequence.
Amino Acid Sequence↗
The cell attachment site on foot-and-mouth disease virus includes the amino acid sequence RGD (arginine-glycine-aspartic acid).
The amino acid sequence RGD (arginine-glycine-aspartic acid) is highly conserved in the VP1 protein of foot-and-mouth disease virus (FMDV), despite being situated in the immunodominant hypervariable region between amino acids 135 and 160. RGD-containing proteins are known to be important in promoting cell attachment in several different systems, and we report here that synthetic peptides containing this sequence are able to inhibit attachment of the virus to baby hamster kidney (BHK) cells. Inhibition was dose-dependent and could be reversed on removal of the peptide. A synthetic peptide corresponding to a portion of the same hypervariable region but not containing the RGD sequence did not inhibit virus attachment under the same conditions. Antibody against the RGD region of VP1 blocked attachment of the virus to BHK cells, and neutralizing monoclonal antibodies, which neutralize virus by preventing cell attachment, were blocked by RGD-containing peptides from binding virus in an ELISA test. Cleavage of the C-terminal region of virus VP1 in situ with proteolytic enzymes reduced cell attachment, and antiserum against a peptide corresponding to this region was also able to inhibit attachment of virus to BHK cells. These results indicate that the amino acid sequence RGD at positions 145 to 147 and amino acids from the C-terminal region of VP1 (positions 203 to 213) contribute to the cell attachment site on FMDV for BHK cells.
Amino Acid Sequence↗
Neutralizing epitopes of type O foot-and-mouth disease virus. I. Identification and characterization of three functionally independent, conformational sites.
Eleven neutralizing monoclonal antibodies (MAbs) were produced to the O1BFS 1860/67 strain of foot-and-mouth disease virus (FMDV), and were characterized for their ability to bind viral and subviral antigens in different ELISA tests and to neutralize heterologous type O isolates. Neutralization escape variants of the homologous virus, isolated under pressure from five of these MAbs, were used in cross-neutralization tests with all of the 11 antibodies. These studies identified three functionally independent, conformational, neutralizing sites. The most conformationally dependent site bound antibody which neutralized a range of type O virus isolates. A second site was less dependent on conformation and was recognized by antibody that was strain-specific. The least conformational site bound MAbs which showed limited cross-neutralization of other type O strains. This latter site appeared to be immunodominant and contained several overlapping epitopes which showed some differences in their specificities. Isoelectrofocusing and sequencing studies of the variants strongly suggested that polypeptide VP2 contributes to the immunodominant site.
Animals↗
Neutralizing epitopes of type O foot-and-mouth disease virus. II. Mapping three conformational sites with synthetic peptide reagents.
Four neutralizing monoclonal antibodies (MAbs), recognizing three functionally independent, conformational sites on type O foot-and-mouth disease virus (FMDV) failed to react with immobilized structural proteins or synthetic peptides but bound to the isolated capsid protein VP1 and peptides in solution. Inhibition ELISA techniques were, therefore, applied using peptide antigens and anti-peptide sera to block MAb binding to virus particles, permitting the identification of those portions of the VP1 protein contributing to the epitopes. The binding site of one MAb, which neutralized a range of type O FMDV isolates, was shown to have components within regions 146 to 150 and 200 to 213 of VP1 with a critical involvement of the amino acids at positions 146 and 206 or 207. The determinants recognized by two other MAbs which were directed at similar, but not identical, epitopes from a second site included components from the 200 to 213 and 143 to 146 regions with amino acids 143 and 144, respectively, appearing critical for the inhibition of the virus binding of the two antibodies. These results demonstrate that the two previously identified immunogenic tracts of VP1 are brought into proximity in the quaternary structure of the virion to form an antigenic domain containing several conformational epitopes, some of which are functionally independent. A fourth, strain-specific MAb was effectively blocked from reacting with virus by peptides corresponding to residues 161 to 180 and 200 to 213.
Amino Acid Sequence↗
The classification and nomenclature of viruses: summary of results of meetings of the International Committee on Taxonomy of Viruses in Edmonton, Canada 1987.
Explore the source record for details and available documents.
Plant Viruses↗
The selective dopamine antagonist properties of BRL 34778: a novel substituted benzamide.
BRL 34778, exo-4-amino-5-chloro-2-methoxy-N-[9-(4-fluorophenylmethyl)-9-azabi cyclo(3.3.1) non-3-yl]-benzamide, is a very potent and specific dopamine D2-receptor antagonist. It exhibits a Ki value of 2.14 nM for dopamine D2-receptors but much lower affinity for D1-(Ki 5700 nM) and for many other receptor types. Its action is potent and of long duration in models for antipsychotic activity (4 h ED50s PO are 0.017 mg/kg for antagonism of apomorphine-induced climbing in mice and 0.028 mg/kg for antagonism of amphetamine-induced locomotion in rats). In contrast to its high potency in models for antipsychotic activity, BRL 34778 is much weaker in models for extrapyramidal effects and sedation (4 h ED50s PO are 2.4 mg/kg for inducing catalepsy in rats and 1.14 mg/kg for inhibition of rearing behaviour in rats). These data indicate potent activity of BRL 34778 in models for antipsychotic activity but low activity in models for extrapyramidal effects and sedation.
Adenylyl Cyclase Inhibitors↗
A new and sensitive method for measuring thermal nociception in cutaneous hyperalgesia.
A method to measure cutaneous hyperalgesia to thermal stimulation in unrestrained animals is described. The testing paradigm uses an automated detection of the behavioral end-point; repeated testing does not contribute to the development of the observed hyperalgesia. Carrageenan-induced inflammation resulted in significantly shorter paw withdrawal latencies as compared to saline-treated paws and these latency changes corresponded to a decreased thermal nociceptive threshold. Both the thermal method and the Randall-Selitto mechanical method detected dose-related hyperalgesia and its blockade by either morphine or indomethacin. However, the thermal method showed greater bioassay sensitivity and allowed for the measurement of other behavioral parameters in addition to the nociceptive threshold.
Animals↗
Use of peptides for immunization against foot-and-mouth disease.
A peptide corresponding to the major immunogenic site of the protein VP1 of foot-and-mouth disease virus (FMDV) will elicit a protective neutralizing antibody response in guinea-pigs, cattle and pigs. The response is much greater when the peptide is presented as a linear dimer or tetramer and pigs receiving as little as 40 micrograms peptide have been protected against challenge infection. An even greater response is obtained when the peptide is presented as part of the core protein of hepatitis B virus. Moreover, responsiveness to the peptide in non-responder mice can be stimulated by the simultaneous inoculation of an appropriate T-cell epitope linked to the FMDV peptide.
Animals↗
Qualitative and quantitative differences in the immune response to foot-and-mouth disease virus antigens and synthetic peptides.
In cross-immunization studies using foot-and-mouth disease virus (FMDV) antigens and a synthetic peptide, from a region within virus coat protein VP1, it has been shown that intact virus will prime the immune system for intact virus, virus subunits and synthetic peptide but not for disrupted virus. In contrast, peptide will prime for a response to peptide and virus subunits but not to intact virus or disrupted virus. Furthermore, studies on antibody populations in anti-virus and anti-peptide antisera demonstrated clear differences in the nature of the antibody response to the two antigens. This result is reflected in protection studies carried out on animals immunized with virus particles or peptides where there is a clearer correlation between in vitro neutralization and protection in vivo following peptide immunization. Thus, it has been shown that there are major qualitative and quantitative differences in the immune response to the FMDV particle and synthetic peptide.
Animals↗
A high proportion of anti-peptide antibodies recognize foot-and-mouth disease virus particles.
Synthetic peptides representing the amino acid sequence 141-160 of the structural protein VP1 of foot-and-mouth disease virus (FMDV) elicit virus-neutralizing antibody. Absorption of anti-peptide sera with purified virus particles removed all detectable virus-binding and neutralizing activity, and reduced the ELISA titres against the homologous peptide by 31-41%. The proportion of anti-peptide antibodies that also recognized virus was unaffected by whether the peptide had been inoculated free, carrier-linked or as part of a fusion protein. The majority of these antibodies reacted with sites composed of residues 142-150. Peptides extended at the amino terminus, into regions shown to be poorly antigenic on the intact virus, induced greater neutralizing responses by increasing the proportion of virus-binding antibodies recognizing region 141-150 from 35% to 70%. However, the total proportion of activity against the longer homologous peptide removed by virus absorption remained within the range 31-41%.
Antibodies, Viral↗
Cytogenetic studies in Dupuytren contracture.
Dupuytren contracture is a connective tissue disease mainly confined to Caucasians. It is characterized by nodular growth and proliferation of collagen in the palmar and plantar fascias. Autosomal dominance with variable penetrance is considered the most likely mode of inheritance. The goal of the present study was to examine the cytogenetics of this common benign neoplasia. Chromosome studies were performed on the nodular growth of eight patients with Dupuytren contracture, all of whom showed chromosome abnormalities that included numerical and structural clones, random numerical and structural aberrations, prophasing, and premature centromere separation. Numerical clones of trisomies 7 and/or 8, as well as some random structural aberrations, were considered to represent in vivo abnormalities, whereas most structural clones appeared likely to be the results of rapid and selective in vitro growth of particular cells. The disease process occurring in Dupuytren contracture was found to involve marked chromosome instability, as well as some in vivo clonal formation. Transverse fascial tissue, usually considered to be uninvolved in the disease process, unexpectedly showed all the same types of abnormalities as the nodular tissue. This indicates a more widespread distribution of disease in the tissues than previously suspected. The findings in the present study are similar to those in various malignant and benign types of tumorous growth and suggest the importance of further cytogenetic investigation into other conditions of benign growth.
Aneuploidy↗
Unconventional viruses and the central nervous system.
Explore the source record for details and available documents.
Central Nervous System↗
Crystallization and preliminary X-ray diffraction analysis of foot-and-mouth disease virus.
Foot-and-mouth disease virus has been crystallized with the objectives of (1) determining the composition and conformation of the major immunogenic site(s) and (2) comparing its structure with those of the related polio, rhino and Mengo viruses, representing the other three genera of the picornaviruses. Most of the work has been done with virus strain O1BFS 1860, which crystallized as small rhombic dodecahedra of maximum dimension 0.3 mm. Virus recovered from crystals was infectious, and was indistinguishable from native virus both in protein composition and buoyant density. The stability of the crystals in the X-ray beam was comparable with that of other picornavirus crystals and they diffracted to a resolution of better than 2.3 A. Initial analysis of the X-ray diffraction data shows the virus to be positioned on a point of 23 symmetry in a close-packed array so that examples of all the icosahedral symmetry elements, except the 5-fold axes, are expressed crystallographically. The cell dimensions are a = b = c = 345 A, alpha = beta = gamma = 90 degrees, with a space group of I23. The diameter of the virus particle is 300 A. Despite the small size of the crystals, diffraction data have been collected to a reasonable resolution using a synchrotron source. Phasing of the diffraction data will be attempted using the methods of molecular replacement.
Aphthovirus↗
A synthetic peptide which elicits neutralizing antibody against human rhinovirus type 2.
Synthetic peptides corresponding to six predicted immunogenic sites on human rhinovirus type 2 (HRV2) have been tested for their reactivity with an anti-virion antibody and for their ability to elicit neutralizing antibody. Four of the peptides reacted with HRV2 antiserum in an indirect ELISA. Rabbit antisera produced to three of these four peptides, one each from VP1, VP2 and VP3, reacted with the virus in an indirect ELISA and with the corresponding proteins by Western blotting. Furthermore, antiserum to one of the peptides, designed to cover the neutralization epitope NIm-II on VP2, not only reacted well in a sandwich ELISA and in an immunoprecipitation test but also neutralized virus infectivity.
Animals↗
Fusion proteins with multiple copies of the major antigenic determinant of foot-and-mouth disease virus protect both the natural host and laboratory animals.
Proteins consisting of one, two or four copies of the amino acid sequence 137 to 162, which contains the major immunogenic site of VP1 of foot-and-mouth disease virus, attached to the N-terminus of beta-galactosidase have been expressed in Escherichia coli cells. In guinea-pigs the protein containing one copy (P71) of the viral determinant elicited only low levels of neutralizing antibody whereas protective levels were elicited by the proteins containing two (P72) or four (P74) copies of the determinant. Single inoculations of the P72 and P74 proteins containing as little as 2 micrograms or 0.8 micrograms of peptide respectively were sufficient to protect all the animals against challenge infection. Moreover, the equivalent of 40 micrograms of peptide in P74 protected pigs against challenge infection after one inoculation.
Adjuvants, Immunologic↗