Asthma, BMI and the Antibody Response to H3N2 and H1N1 Influenza Virus Strains Following Vaccination
Creators: name: Meade, Anna
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2016

description: Asthma is a common disease of chronic airway inflammation that has multiple triggers
that cause malfunction of the lungs. Because asthma affects the airways by inducing
inflammation and causing narrowing, an influenza virus infection is more likely to cause severe
symptoms in an asthmatic. As influenza vaccination is the best protection from influenza
infection, this study was to explore the vaccine response of asthmatic and matched control (i.e.
non-asthmatic) human subjects. In addition, the effect of BMI on the asthmatic response to
vaccination was also explored. Previous work in our lab had demonstrated that increasing BMI
was associated with a decreased response to vaccination. Therefore, a higher BMI in an
asthmatic may result in a poorer response to vaccine. Serum was collected from subjects pre and
30 days post influenza vaccination. Antibody titers were measured to the H3N2 and H1N1 virus
strains represented in that year’s (2015) vaccine. There was a significant increase in antibody
response post vaccination among both asthmatic and control groups. There was also significant
difference in asthmatic and control groups between antibody fold increase pre and post
vaccination with asthmatics having a greater fold increase than the control group. Prevaccination,
asthmatic subjects tended to start with a lower antibody titer and post-vaccination
had comparable or greater antibody titer than their control counterparts. This suggests that
asthmatics may not be able to maintain their antibody response to the same extent as nonasthmatics.
I. Specific Aims
Asthma is present on average in 1 in 12 adults. In the last decade, the proportion of
people in the United States with asthma grew by 15%1. The inflammatory disease was
the most common comorbidity observed among patients hospitalized with influenza A
virus during the 2009 pandemic2. Little is known about how the asthmatic phenotype
influences protective immune responses against respiratory viral pathogens.
A mouse-model study conducted by Furuya et al. demonstrated a causal link
between defective antibody responses and heightened susceptibility of asthmatic mice to
influenza infection2. This suggests that asthmatics have a defective immune response
when exposed to the influenza virus when compared to non-asthmatics. This leads us to
ask: Will an impaired immune response be observed in human asthmatic subjects and is
the influenza vaccine as effective in asthmatic subjects? Furthermore, could obesity also
further impair the asthmatic response to vaccine?
Aim 1: Determine the vaccine antibody titer of matched subjects pre and post vaccination using
the influenza hemmaglutinaiton inhibition (HAI) assay against the H3N2 virus. The hypothesis
is that both asthmatics and non-asthmatics will have a higher antibody titer post vaccination, but
that asthmatics will have a lower antibody titer for both pre and post vaccination.
Aim 2: Determine the vaccine antibody response of matched subjects pre and post vaccination
using the HAI assay against the H1N1 virus. The hypothesis is that both asthmatics and nonasthmatics
will have a higher antibody titer post vaccination, but again asthmatics will have a
lower antibody titer for both pre and post vaccination.
Aim 3: Determine if increasing BMI contributes to a poorer vaccine response in asthmatics
compared with controls. Previous studies have found that obesity results in a weakened immune
response. The hypothesis is that asthmatics in the obese class I and II BMI category (i.e. 4 and
5) will have a lower antibody titer than obese non-asthmatics.
The overall objective of this study is to determine if asthmatics overall have an impaired
influenza vaccine response and if obesity furthers reduces the response. Results from this study
can lend insight into an asthmatic’s immune response and we can attempt to identify mechanisms
that affect their immune response to ultimately develop specific asthmatic preventative and
treatment measures to the influenza virus.