17 research outputs found

    Species-Specific and Cross-Reactive IgG1 Antibody Binding to Viral Capsid Protein 1 (VP1) Antigens of Human Rhinovirus Species A, B and C

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    <div><p>Background</p><p>Human rhinoviruses (HRV) are associated with upper and lower respiratory illnesses, including severe infections causing hospitalization in both children and adults. Although the clinical significance of HRV infections is now well established, no detailed investigation of the immune response against HRV has been performed. The purpose of this study was to assess the IgG1 antibody response to the three known HRV species, HRV-A, -B and -C in healthy subjects.</p><p>Methods</p><p>Recombinant polypeptides of viral capsid protein 1 (VP1) from two genotypes of HRV-A, -B and -C were expressed as glutathione S-transferase (GST) fusion proteins and purified by affinity and then size exclusion chromatography. The presence of secondary structures similar to the natural antigens was verified by circular dichroism analysis. Total and species-specific IgG1 measurements were quantitated by immunoassays and immunoabsorption using sera from 63 healthy adults.</p><p>Results</p><p>Most adult sera reacted with the HRV VP1 antigens, at high titres. As expected, strong cross-reactivity between HRV genotypes of the same species was found. A high degree of cross-reactivity between different HRV species was also evident, particularly between HRV-A and HRV-C. Immunoabsorption studies revealed HRV-C specific titres were markedly and significantly lower than the HRV-A and HRV-B specific titres (<i>P</i><0.0001). A truncated construct of HRV-C VP1 showed greater specificity in detecting anti-HRV-C antibodies.</p><p>Conclusions</p><p>High titres of IgG1 antibody were bound by the VP1 capsid proteins of HRV-A, -B and -C, but for the majority of people, a large proportion of the antibody to HRV-C was cross-reactive, especially to HRV-A. The improved specificity found for the truncated HRV-C VP1 indicates species-specific and cross-reactive regions could be defined.</p></div

    An example of the level of cross-reactivity found between HRV species and HPV Sabin VP1 in an individual’s serum.

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    <p>(A) HRV-A VP1 antigen inhibited by HRV-B, HRV-C and HPV Sabin antigens. (B) HRV-B VP1 antigen inhibited by HRV-A, HRV-C and HPV Sabin antigens. (C) HRV-C VP1 antigen inhibited by HRV-A, HRV-B and HPV Sabin antigens. (D) HPV Sabin antigen inhibited by antigens representing the three HRV species. An irrelevant recombinant antigen (Fel d 3) was used as a negative control for each competitive inhibition assay (data not shown).</p

    Antibody responses to HRV-C VP1 with an N-terminal truncation in 30 adult subjects.

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    <p>(A) IgG1 binding (ng/ml) to truncated HRV-C3 VP1 expressed from residue 14 to 275, in comparison to full-length VP1. <i>P</i><0.0001 between full-length and truncated HRV-C3 VP1. (B) Correlation of IgG1 binding (ng/ml) between full-length HRV-C3 VP1 pre-absorbed with HRV-A to remove cross-reactivity to HRV-A, and truncated HRV-C3 VP1. A reference sera and three negative sera that did not have IgG1 binding to HRV-C3, as determined by the immunoassays and immunoabsorptions, were included on every plate for quantitation of binding.</p

    Innate (24 hour) cytokine production.

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    <p>In vitro cytokine production by HC (open circles) and CSLD (filled circles) PBMC following 24 hour challenge with NTHi. Delta concentration (NTHi challenge minus nil challenge) with median and IQR.</p