Specific Recognition of Influenza A/H1N1/2009 Antibodies in Human Serum: A Simple Virus-Free ELISA Method

Abstract

BackgroundAlthough it has been estimated that pandemic Influenza A H1N1/2009 has infected millions of people from April to October 2009, a more precise figure requires a worldwide large-scale diagnosis of the presence of Influenza A/H1N1/2009 antibodies within the population. Assays typically used to estimate antibody titers (hemagglutination inhibition and microneutralization) would require the use of the virus, which would seriously limit broad implementation.Methodology/Principal FindingsAn ELISA method to evaluate the presence and relative concentration of specific Influenza A/H1N1/2009 antibodies in human serum samples is presented. The method is based on the use of a histidine-tagged recombinant fragment of the globular region of the hemagglutinin (HA) of the Influenza A H1N1/2009 virus expressed in E. coli.Conclusions/SignificanceThe ELISA method consistently discerns between Inf A H1N1 infected and non-infected subjects, particularly after the third week of infection/exposure. Since it does not require the use of viral particles, it can be easily and quickly implemented in any basic laboratory. In addition, in a scenario of insufficient vaccine availability, the use of this ELISA could be useful to determine if a person has some level of specific antibodies against the virus and presumably at least partial protection.

Immunogenicity, Boostability, and Sustainability of the Immune Response after Vaccination against Influenza A Virus (H1N1) 2009 in a Healthy Population

“…This is caused by the use of various influenza virus strains and different receptor-destroying enzymes (homemade or commercially bought) and also by differences in quality and nature of red blood cells (1). Therefore, there is a poor reproducibility of the HI assay between laboratories.…”

Engineering of virus-like particles for alternative vaccine candidate targeting a hypervariable peptide antigen element

“…Thus, in order to obtain antibodies that cross-react with the native antigen protein, the epitope peptides need to maintain conformational integrity (Purcell et al 2007, Purcell et al 2003). The quality of antibodies has been shown to resemble the protection efficacy of the antibodies (Alvarez et al 2010 A higher antibody quality indicates a higher potential of protection efficacy, thus a high quality of antibodies is desirable.…”

“…The study by Alvarez et al showed that the quality of the antibodies reflects the protective efficacy of the antibodies (Alvarez et al 2010). A higher antibody quality indicates a greater potential protection efficacy.…”

“…Thus, in order to obtain antibodies that cross-react with the native antigen protein, the epitope peptides need to maintain conformational integrity (Purcell et al 2007, Purcell et al 2003). The quality of antibodies has been shown to resemble the protection efficacy of the antibodies (Alvarez et al 2010 A higher antibody quality indicates a higher potential of protection efficacy, thus a high quality of antibodies is desirable.Studies in modular VLPs presume that it is nearly impossible for a peptide antigen element to assume its conformational integrity when it is presented on a modular VLP (Jennings and Bachmann 2007, Tissot et al 2010. Until now, presentation of a peptide antigen element on a modular VLP and the impact of display strategy for presentation of the antigen element on the quality of the resulting antibodies are not fully understood.…”

“…61 The findings reported in Chapter 3 lead us to the question what improvements can be made to the tandem repeat display strategy to induce antibodies of a higher quality? A higher quality of antibodies is desired because the quality of antibodies has been shown to represent the protection level of the antibodies (Alvarez et al 2010). In an attempt to increase the quality of antibody, two approaches are explored in this chapter: (i) the use of adjuvants, and (ii) increasing the number of tandem repeat H190.…”