Pandemic 2009 H1N1 vaccination produces antibodies against multiple flu strains

[Shiloh]

Source: http://www.eurekalert.org/pub_releases/2012-05/eu-p2h051612.php

Public release date: 21-May-2012


Contact: Holly Korschun
hkorsch@emory.edu
404-727-3990
Emory University

Pandemic 2009 H1N1 vaccination produces antibodies against multiple flu strains
Discovery brings researchers closer to goal of 'universal' flu vaccine

The pandemic 2009 H1N1 vaccine can generate antibodies in vaccinated individuals not only against the H1N1 virus, but also against other influenza virus strains including H5N1 and H3N2. This discovery adds an important new dimension to the finding last year that people infected with pandemic 2009 H1N1 virus produced high levels of antibodies that were broadly cross-reactive against a variety of flu strains.

Development of a "universal" influenza vaccine that protects against multiple viral subtypes has long been the goal of immunologists working to overcome the requirement for a new vaccine during each flu season and the need for a rapid response to potentially dangerous mutations.

The new discovery brings the researchers closer to being able to design a pan-influenza vaccine that reliably induces broadly cross-reactive antibodies at sufficiently high levels to protect against different influenza subtypes.

The findings are published this week in the Proceedings of the National Academy of Sciences (PNAS). The researchers are from Emory University, the University of Chicago, and the National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health (NIH)...

 

[Giuseppe]

Re: Pandemic 2009 H1N1 vaccination produces antibodies against multiple flu strains

[Source: Proc Natl Acad Sci USA, full text: (LINK). Abstract, edited.]

Human B cell responses to pandemic H1N1 vaccine [Immunology]



Li, G.-M., Chiu, C., Wrammert, J., McCausland, M., Andrews, S. F., Zheng, N.-Y., Lee, J.-H., Huang, M., Qu, X., Edupuganti, S., Mulligan, M., Das, S. R., Yewdell, J. W., Mehta, A. K., Wilson, P. C., Ahmed, R.

We have previously shown that broadly neutralizing antibodies reactive to the conserved stem region of the influenza virus hemagglutinin (HA) were generated in people infected with the 2009 pandemic H1N1 strain. Such antibodies are rarely seen in humans following infection or vaccination with seasonal influenza virus strains. However, the important question remained whether the inactivated 2009 pandemic H1N1 vaccine, like the infection, could also induce these broadly neutralizing antibodies. To address this question, we analyzed B-cell responses in 24 healthy adults immunized with the pandemic vaccine in 2009. In all cases, we found a rapid, predominantly IgG-producing vaccine-specific plasmablast response. Strikingly, the majority (25 of 28) of HA-specific monoclonal antibodies generated from the vaccine-specific plasmablasts neutralized more than one influenza strain and exhibited high levels of somatic hypermutation, suggesting they were derived from recall of B-cell memory. Indeed, memory B cells that recognized the 2009 pandemic H1N1 HA were detectable before vaccination not only in this cohort but also in samples obtained before the emergence of the pandemic strain. Three antibodies demonstrated extremely broad cross-reactivity and were found to bind the HA stem. Furthermore, one stem-reactive antibody recognized not only H1 and H5, but also H3 influenza viruses. This exceptional cross-reactivity indicates that antibodies capable of neutralizing most influenza subtypes might indeed be elicited by vaccination. The challenge now is to improve upon this result and design influenza vaccines that can elicit these broadly cross-reactive antibodies at sufficiently high levels to provide heterosubtypic protection.
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