The Effect of Pregnancy on Immune Responses to H1N1 Influenza Virus Infection Pubblico
Littauer, Elizabeth (Spring 2018)
Abstract
In 2009, the H1N1 swine flu pandemic highlighted the vulnerability of pregnant women to influenza viral infection. Pregnant women infected with influenza A virus were at increased risk of hospitalization due to severe acute respiratory distress syndrome (ARDS), and rates of morbidity and mortality among infected pregnant women were five-fold higher than the non-pregnant infected population. Moreover, newborns born to mothers infected mid-gestation had an increased risk of preterm birth or low birth weight. Pregnant women have a unique immunological profile modulated by the sex hormones required to maintain pregnancy, namely progesterone and estrogen. In this dissertation, I describe H1N1 influenza A viral pathogenesis during pregnancy, the crosstalk between innate immune signaling and hormonal regulation, and the role of pregnancy hormones in modulating cellular responses to virus infection mid- to late gestation. In a pregnant mouse model, I highlight the ways in which lung architecture and function is perturbed by pregnancy and demonstrated that infection with lethal doses of seasonal H1N1 A/Brisbane59/07 disrupts progesterone expression and upregulates cyclooxygenase-2 (COX-2) and prostaglandins, resulting in placental degradation, pre-term labor and spontaneous abortions.
I also investigate mechanisms by which pregnancy alters activation and maturation of cellular immune responses to pandemic H1N1 A/California/07/2009 influenza viral infection. Pregnant mice infected mid-gestation with sublethal doses of H1N1 A/California/07/09 exhibited reduced serum influenza-specific antibody avidity and HAI titers compared to infected non-pregnant controls despite equivalent activation of H1N1-specific antibody secreting cells up to 6 weeks post infection. While pregnancy reduced the frequency of lung-resident CD4+ T cells, virus-specific IFN-γ secreting and IgA-secreting cells were increased in the lungs 42 d.p.i. These data suggest that the condition of pregnancy enhances cellular responses to H1N1 infection within the mucosa following offspring delivery and maternal recovery while overall antibody quality is weakened due to immune suppression during gestation.
Finally, I highlight advancements in the field of reproductive immunology in response to viral infection and illustrate how that knowledge might utilized to develop more effective post-infection therapies and vaccination strategies during pregnancy.
Table of Contents
CHAPTER I: Introduction
1
CHAPTER II: H1N1 influenza virus infection results in adverse
pregnancy outcomes by disrupting tissue-specific hormonal regulation
13
Abstract
14
Author summary
15
Introduction
16
Results
20
Discussion
31
Materials and Methods
38
Acknowledgments
43
References
44
Figure 1. Influenza infection inhibits gestational development and offspring health.
61
Figure 2. Pregnancy results in increased inflammation in the lungs and enhanced viral growth in lungs but not detected in placenta.
63
Figure 3. Viral infection disproportionately reduces cytokine and hormone expression in the sera and lungs during pregnancy.
65
Figure 4. Pregnancy increases lung tissue expression of proinflammatory cytokines and chemokines while dampening the upregulation of progesterone and PGF2α following infection.
67
Figure 5. Infection increases placental expression of contraction-inducing PGF2α and reduces pregnancy-supportive progesterone.
68
Figure 6. Infection damages placental architecture and increases activation of structural protein degrading matrix metalloproteinases (MMPs).
70
Figure 7. Infection changes pregnancy-supportive PIBF expression in the placenta and lungs.
72
Figure 8. Infection and pregnancy increase COX-2 expression in the lungs.
73
Supplementary Figure 1. Viral titer in the lungs affects expression of progesterone and PGF2α in a compartment-specific manner.
74
Supplementary Figure 2. Infection and pregnancy impact cytokine expression in a compartment-specific manner.
76
Supplementary Table 1. Serum chemokine and cytokine levels 4 days post-infection.
77
Supplementary Table 2. Lung chemokine and cytokine levels 4 days post-infection.
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Supplementary Table 3. Placental and fetal chemokine and cytokine levels 4 days post-infection.
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CHAPTER III: Pregnancy dysregulates innate immune responses to 2009 H1N1 influenza viral infection and the efficacy of long term anti-influenza antibodies
80
Abstract
81
Introduction
82
Materials and Methods
85
Results
89
Discussion
97
Acknowledgments
101
References
103
Figure 1. H1N1 influenza virus infection results in increased pathogenicity during pregnancy.
115
Figure 2. Hormone and cytokine expression in lung tissue 4 dpi and 7 dpi.
117
Figure 3. Hormone and cytokine expression in serum samples 4 dpi and 7 dpi.
119
Figure 4. Hormone and cytokine expression in placental tissue 4 dpi and 7 dpi.
121
Figure 5. Innate immune activation following H1N1 influenza virus infection.
123
Figure 6. Germinal center reactions and plasmablast activation.
124
Figure 7. Pregnancy increases virus-specific IgA-secreting cells in the lungs 6 weeks post infection.
125
Figure 8. Pregnancy induces increased IgG expression with reduced avidity and HAI titers.
126
Figure 9. Pregnancy increases virus-specific IFN-γ secreting cells in the lungs 6 weeks post infection.
127
Figure 10. Pregnancy induces an IgG2a-specific response to boost vaccination 42 d.p.p.
128
Figure 11. Activation of vaccine-specific B and T cells following vaccination during pregnancy and boost post-weaning.
129
Suppl Fig 1. Gating settings for flow cytometry.
130
Suppl Table 1. Lung cytokine expression.
132
Suppl Table 2. Sera cytokine expression.
134
Suppl Table 3. Placental cytokine expression.
136
CHAPTER IV: CONCLUSIONS
137
REFERENCES
144
APPENDIX I: Stable incorporation of GM-CSF into dissolvable microneedle patch improves skin vaccination against influenza
169
Abstract
170
Introduction
171
Materials and Methods
174
Results
182
Discussion
192
Conclusions
195
Acknowledgments
196
References
197
Figure 1. Adjuvantation with 100 ng GM-CSF in intradermal H1N1 A/California/07/09 subunit vaccination improves antibody responses and enhances protection to lethal virus challenge.
207
Figure 2. GM-CSF is an effective adjuvant at low doses in H3N2 vaccinations.
209
Figure 3. GM-CSF retains proliferative capacity in bone marrow cells following MN patch fabrication and dissolution.
211
Figure 4. GM-CSF retains bioactivity following fabrication with a range of MN excipients.
212
Figure 5. The inclusion of GM-CSF in MN patches in H1N1 influenza vaccination is dose-sparing and generates superior IgG expression against homologous and heterologous HAs compared to ID and IM vaccination
214
Figure 6. H1N1 subunit vaccination with GM-CSF improved protection of mice from lethal H1N1 influenza challenge
216
Figure 7. GM-CSF improved antibody responses and avidity when included in MN patch vaccination.
217
Figure 8. Inclusion of GM-CSF enhanced activation of B cells in spleen and bone marrow.
219
Fig 9. MN patch vaccination with GM-CSF increased CD8+ T cell responses in inguinal lymph nodes (ILN) and vaccine-specific IFN-γ responses in the spleen.
220
Fig. 10. GM-CSF adjuvanted MN patch immunization improved cross-reactive neutralization responses between homologous and heterologous viral strains.
222
Fig. 11. Th1 cytokine responses to viral infection were increased in GM-CSF-adjuvanted MN vaccinated mice.
223
Supplementary Figure 1. Gating strategies for flow cytometry.
224
Supplementary Figure 2. Activation of T cells in inguinal lymph nodes (ILN) and spleen.
225
Supplementary Figure 3. Cross-reactive antibody titers against H1N1 and H3N2 viruses
226
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