Dose-response relationships in a microneutralization test for foot-and-mouth disease viruses

SUMMARYThe reaction of foot-and-mouth disease virus (FMDV) with 12S subunit/140S virion cross-reactive (sensitizing) antibody was studied in order to elucidate the requirements for neutralization versus sensitization. The presence of sensitizing antibody in immune serum caused an atypical in vitro neutralization response curve and a non-neutralized fraction. Cell-associated (cytophilic) antibody was not present in the system. Dissociation of the immune complex was not a factor and sensitized virus adsorbed to host cells via the regutar virus receptor site(s). This finding led to the conclusion that sensitizing antibody is specific for non-critical sites. Dosing of the neutralization reaction mixtures with fractionated antibody of alternative antigenic specificities had an antagonistic effect on the neutralization response, suggesting steric hindrance. Cell receptor sites were a factor in sensitization since different host systems had different susceptibilities for sensitized antigen. The results suggest that in vitro neutralization of FMDV requires the attachment of multiple antibody molecules as proposed by the multi-hit theory of neutralization. The in vitro measurement of serum neutralizing activity as an indication of the in vivo immune response is discussed.

Section: Discussionsupporting

confidence: 66%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Neutralization of Foot-and-Mouth Disease Virus. II. Further Parameters Related to the Sensitization of the 140S Virion by Antibody

Hardy

Moore

1982

“…This was performed using a two-dimensional microneutralization technique similar to that described by Booth et al (1978). Briefly, doubling dilutions of antibody were reacted with halflogx0 dilutions of virus for 2 h, HeLa cells were added as indicators of residual infectivity and the microplates were incubated at 34 °C for 5 days prior to fixing and staining.…”

Section: Methodsmentioning

confidence: 99%

Characterization of monoclonal antibodies raised against a synthetic peptide capable of inducing a neutralizing response to human rhinovirus type 2

Barnett

Rowlands

Parry

1993

Synthetic peptides incorporating the derived amino acid sequence of VP2 residues 156 to 170 of human rhinovirus type 2 (HRV2) have previously been shown to elicit antibodies that neutralize virus infectivity. The proportion of virus-reactive antibodies present in polyclonal antisera to these peptides is, however, very low. Moreover, neutralization titrations of such antisera correlate poorly with other assays of either anti-virus or anti-peptide activity, suggesting the presence of antibodies with different specificities. To investigate these findings further, we produced a panel of monoclonal antibodies (MAbs) to VP2 peptides of residues 156 to 170 and characterized their reactions with a range of antigens in ELISA, precipitation and neutralization titrations. All the MAbs obtained recognized the homologous peptide, but could be divided into four main reaction groups according to their specificity for viral antigens. Antibodies in the first group recognized and neutralized native virus, apparently by preventing attachment to cells. A second group of MAbs bound to intact particles with similar affinities to the first group, but failed to neutralize infectivity. Antibodies in the third group recognized virus only after capsid distortions incurred by heating or by previous reaction with polyclonal antibodies. The fourth group comprised MAbs that were mainly peptide-specific. Some possible applications of anti-peptide MAbs to improving the design of peptide immunogens are considered.

“…The in vitro neutralization reaction ideally results in complete inhibition of viral infectivity. However, non-neutralized fractions resulting from the incomplete neutralization of animal virus populations by homologous antibody have frequently been reported for many viruses, including foot-and-mouth disease virus (FMDV) (Dulbecco et al, 1956;Bradish et al, 1962;Philipson, 1966;Fiala, 1969;Lewenton-Kriss & Mandel, 1972;Mandel, 1976;Rweyemamu et al, 1977;Booth et al, 1978). Non-neutralized fractions have been identified for such a large variety of virus-antiserum-cell systems (Daniels, 1975;Della-Porta & Westaway, 1978) that their existence should perhaps be considered a general characteristic.…”

Section: Introductionmentioning

confidence: 99%

Neutralization of Foot-and-Mouth Disease Virus. I. Sensitization of the 140S Virion by Antibody Also Reactive with the 12S Protein Subunit

Hardy¹,

Moore

1981

SUMMARYThe in vitro interaction of foot-and-mouth disease virus (FMDV) with an immune serum resulted in a fraction of virus which failed to be neutralized. This inability of antibody to neutralize the entire population of a virus preparation was studied with emphasis on the antigenic specificity of the antibody-virus reaction. Antibody to FMDV recognized multiple antigenic determinants. Immunoadsorbent fractionation of the serum into 12S subunit cross-reactive and 140S virion-specific antibody revealed that these multiple antigenic determinants are factors in determining the neutralizing ability of the antibody. Antibody specific to the infective 140S virion neutralized virus effectively, whereas antibody reactive with both the 140S virion and 12S non-infective component did so ineffectively. Neutralization was independent of viral aggregation, strain, or type heterogeneity, dissociation of the immune complex, heterogeneity of antibody class, or incubation time. The non-neutralized fraction of virus was not due to insufficient antibody in the system, was demonstrated to be complexed with antibody ('sensitized') and could be neutralized with anti-globulin serum. The findings demonstrate the heterogeneity of antibody specificity to FMDV in serum preparations and relate the importance of antibody specificity to the neutralization of virus in vitro.