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Evaluation of the antiviral, adjuvant and immunomodulatory effects of a [beta]-(1,4)-linked polymannose (Acemannan)
This study examined the antiviral, adjuvant and immunomodulatory effects of acemannan (ACE-M), a long-chain polydispersed β-(1,4)-linked mannose polymer. Antiviral effects were determined in vitro. Newcastle disease virus (NDV) infected secondary chicken embryonic fibroblast (CEF) monolayers were cultured in the presence of ACE-M and molecular and biological procedures were used to evaluate effects. Adjuvant and immunomodulatory effects of in vivo administration of ACE-M were evaluated using enzyme-linked immunosorbent assay (ELISA) procedures. The same procedures were used to evaluate the effects of in ovo presentation of ACE-M. An ACE-M concentration of 50 μg ml⁻¹ completely inhibited virus replication and following further evaluation using slide hemagglutination and hemadsorption tests, it was postulated that ACE-M alters the functional properties of the NDV glycoproteins, HN and F. To assess ACE-M's effects on viral glycoproteins, NDV-infected CEFs were treated with either 50 or 100 μg ml⁻¹ ACE-M and labeled with (³⁵S) -methionine or (³H) -glucosamine at selected intervals. Both HN and F glycoproteins were then radioimmunoprecipitated and analyzed by electrophoresis on a sodium dodecyl sulfate polyacrylamide gel (SDS-PAGE). Reduction in electrophoretic mobility of both HN and F was observed. Changes were dependent on time of treatment and concentration. It was hypothesized that changes in electrophoretic mobility were due to inhibition of the processing of HN and F glycoprotein oligosaccharides. To test this hypothesis, viral glycoproteins from NDV-infected cultures treated with ACE-M, deoxynojirimycin and deoxymannojirimycin and labeled with (³⁵S) -methionine were immunoprecipitated and analyzed by SDS-PAGE. HN and F glycoproteins immunoprecipitated from ACE-M- and deoxynojirimycin-treated cultures exhibited similar electrophoretic mobilities suggesting ACE-M or a metabolite thereof may block glucosidase I and thereby inhibit the processing of oligosaccharides and the post-translational processing of the glycoproteins, resulting in the production of non- or partially-functional glycoproteins. With respect to the adjuvant and immunomodulatory effects, ACE-M was shown to function primarily as an adjuvant. ACE-M added to either a monovalent or trivalent vaccine and presented in vivo significantly enhanced the immune response to both glycosylated and non-glycosylated antigens. Immunomodulatory effects of ACE-M were most pronounced when ACE-M was inoculated in ovo and antigen was presented on day one of hatch. This method caused a significant increase in antibody titers compared to other methods and may be expected to alter vaccination technology.
SubjectMajor veterinary microbiology
1990 Dissertation C5395
Chinnah, Anthony (1990). Evaluation of the antiviral, adjuvant and immunomodulatory effects of a [beta]-(1,4)-linked polymannose (Acemannan). Texas A&M University. Texas A&M University. Libraries. Available electronically from
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