Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 2007 Strategy to improve swine influenza virus (SIV) vaccination Pravina Kitikoon Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Allergy and Immunology Commons, Medical Immunology Commons, and the Virology Commons Recommended Citation Kitikoon, Pravina, "Strategy to improve swine influenza virus (SIV) vaccination" (2007). Retrospective Theses and Dissertations. 15978. https://lib.dr.iastate.edu/rtd/15978 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. i Strategy to improve swine influenza virus (SIV) vaccination by Pravina Kitikoon A dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Major: Veterinary Microbiology Program of Study Committee: Eileen L. Thacker, Major Professor Bruce H. Janke Brad J. Thacker James A. Roth Patrick G. Halbur Iowa State University Ames, Iowa 2007 Copyright © Pravina Kitikoon, 2007. All rights reserved. UMI Number: 3259502 UMI Microform 3259502 Copyright 2007 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, MI 48106-1346 ii DEDICATION I would like to dedicate my dissertation to my father and mother, Viroj and Prapai Kitikoon the two persons I dearly love and will always keep close to heart. iii TABLE OF CONTENTS LIST OF FIGURES v LIST OF TABLES vi CHAPTER 1. GENERAL INTRODUCTION 1 Statement of problem 1 General objectives and research plan 3 Dissertation organization 5 Literature review 5 CHAPTER 2. VACCINE EFFICACY AND IMMUNE 45 RESPONSE TO SWINE INFLUENZA VIRUS (SIV) CHALLENGE IN PIGS INFECTED WITH PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME VIRUS AT THE TIME OF SIV-VACCINATION Abstract 45 Introduction 46 Materials and methods 47 Results 51 Discussion 57 Acknowledgements 62 References 62 CHAPTER 3. THE IMMUNE RESPONSE AND MATERNAL 67 ANTIBODY INTERFERENCE TO A HETEROLOGOUS H1N1 SWINE INFLUENZA VIRUS INFECTION FOLLOWING VACCINATION Abstract 67 Introduction 68 Materials and methods 70 Results 75 Discussion 81 Acknowledgements 84 References 84 iv CHAPTER 4. THE ANTIBODY RESPONSE TO SWINE 89 INFLUENZA VIRUS (SIV) RECOMBINANT MATRIX 1 (rM1), MATRIX 2 (M2), AND HEMAGGLUTININ PROTEINS IN PIGS WITH DIFFERENT SIV EXPOSURE Abstract 89 Introduction 90 Materials and methods 92 Results 98 Discussion 104 Acknowledgements 108 References 108 CHAPTER 5. THE EFFECT OF THE MATRIX 2 (M2) 114 PROTEIN ON THE EFFICACY OF A COMMERCIAL BIVALENT SWINE INFLUENZA VACCINE Summary 114 Introduction 115 Materials and methods 116 Results 119 Discussion 122 Acknowledgements 124 References 125 CHAPTER 6. GENERAL CONCLUSIONS 129 Summary 129 Future research 134 REFERENCES CITED 136 ACKNOWLEDGEMENTS 164 v LIST OF FIGURES CHAPTER 2. Fig. 1. SIV titers in nasal swabs collected at 2, 5 and 7 days post infection 55 Fig. 2. Average serum hemagglutinin-inhibition (HI) antibody titers to the 55 SIV challenge isolate Fig. 3. SIV-specific IgA antibodies in bronchoalveolar lavage fluid from pigs 57 collected at 7 and 28 days post infection CHAPTER 3. Fig. 1. Mean rectal temperatures (a) and clinical scores (b) 76 Fig. 2. Virus titers in nasal swabs 78 Fig. 3. Mean hemagglutinin inhibition (HI) antibody titers against the vaccine 80 antigen (a) and challenge antigen (b) CHAPTER 4. Fig. 1. Results from sample set 1. Comparison of antibody responses of 3 101 SIV subtypes between single low-dose and high-dose infection of the same subtype at 4 time points (A) HI antibody against homologous virus (B) M2e ELISA (C) rM1 ELISA Fig. 2. Results from sample set 1. Comparison of antibody responses to a 102 low-dose infection of 3 different SIV subtypes followed by a challenge with high-dose homologous virus (A) HI antibody (B) M2e ELISA (C) rM1 ELISA Fig. 3. Immunoperoxidase staining of 3 purified proteins on a polyvinylidene 104 difluoride (PVDF) membrane CHAPTER 5. FIG 1: Mean CD4+ T cells in 10,000 peripheral mononuclear blood cells 122 (PBMCs) that proliferated to cH1N1 or H1N2 antigen vi LIST OF TABLES CHAPTER 1. Table 1. Commercial inactivated swine influenza vaccines in the U.S.A 18 CHAPTER 2. Table 1 Experimental design 48 Table 2 Summary of clinical observations following infection with SIV 52 and/or PRRSV Table 3 Average percentage of macroscopic lesions, microscopic scores 53 and immunohistochemistry (IHC) test in pigs vaccinated against SIV followed by challenge with SIV and/or PRRSV Table 4 Anti-PRRSV antibody response and percent PRRSV-seropositive 57 Pigs during the experiment CHAPTER 3. Table 1 Experimental design-group description, maternal derived antibody 71 (MDA) status, vaccination status, SIV infection status and numbers of pigs necropsied on each necropsy days Table 2 Clinical sign scores 71 Table 3 Percentage of lung with visible macroscopic lesions and microscopic 77 lesion from pigs infected with H1N1 SIV at both necropsies Table 4 Lower airway SIV-specific IgA antibody and T-cell proliferation analysis 81 from pigs following H1N1 SIV infection at 7 weeks of age CHAPTER 4. Table 1. Virus strains used in samples set 1. The low dose was 5 x 106 93 TCID50 and infected when pigs were 5 weeks of age. The high dose 8 was 5 x 10 TCID50 and infected when pigs were 10 weeks of age Table 2. Results from sample set 2 demonstrating means HI titer, M2e ELISA 103 OD and rM1 ELISA OD at 21 days after second vaccination and 7 days after SIV challenge Table 3. Results from serum sample set 3 demonstrating the M2e and rM1 ELISA 103 mean OD ± SD at different HI titers from MDA+ and MDA- pigs. vii CHAPTER 5. TABLE 1: Experimental design 117 TABLE 2: Clinical signs observed following challenge with 120 A/Swine/IA/40776/92 (cH1N1) strain or A/Swine/Indiana/9K035/99 (H1N2) and mean percentage macroscopic lesion and mean microscopic lesion scores at 5 days post-infection TABLE 3: Number of pigs detected with SIV antigen in the lungs at 5 days 120 post infection, (dpi) mean virus titers from nasal swabs and mean OD of serum rM2 antibody at -1 dpi 1 CHAPTER 1. GENERAL INTRODUCTION STATEMENT OF PROBLEM Swine influenza is responsible for significant respiratory disease in the North American pig population. Swine influenza is caused by a RNA virus that belongs to the influenza A virus genus in the family Orthomyxoviridae. It consists of a segmented genome which allows mutation through accumulation of point mutations (antigenic drift) and genetic reassortment between different viruses that co-infect the same cell (antigenic shift) [1]. The first swine influenza virus (SIV) was isolated in 1930 and was known as the classical swine H1N1 (cH1N1) [2,3]. The cH1N1 was the principal etiology of swine influenza in the U.S. for almost 70 years [4]. In 1998, a H3N2 subtype virus emerged in to the U.S. swine population. The H3N2 virus rapidly evolved from a virus that was initially a double reassortant virus consisting of genes of human and swine lineages to a triple reassortant virus that contained human, swine and avian gene lineages [5]. Once established the H3N2 viruses have undergone further reassortment with the cH1N1 viruses resulting in a new H1N2 subtype virus [6]. The appearance of the H3N2 viruses into the North American swine population initiated a shift of virus that significantly changed the epidemiology of SIV. At present, all three subtypes, H1N1, H3N2 and H1N2 are well established in the U.S. swine population and evidence show that the multiple lineages with increased diversity of both genetic and antigenic make-up continue to evolve making control of swine influenza virus increasingly difficult [6-9]. Swine influenza infected pigs exhibit clinical disease consisting of high fever, cough, labored breathing, anorexia, inactivity and an obvious sign of weight loss [10]. Although recovery from SIV infection is generally within 5-7 days, the resulting reduction in weight gain often causes a negative economic impact due to stunned growth and increased numbers of days to reach market weight [10]. A reduction in the number of pigs born alive and abortion in late pregnancy has been reported following outbreaks of swine influenza in naïve sow herds [11-13]. Swine influenza is an important viral component to the porcine respiratory disease complex (PRDC) when combined with porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus type 2, and/or Mycoplasma hyopneumoniae. PRDC typically occurs in pigs at 14 to 20 week of age and causes a 2 significant source of economic loss to swine producers worldwide [14]. In the U.S. alone annual loss due to PRDC was estimated to exceed $210 million in the year 2002 [15] Vaccination is the most common strategy used to control SIV-induced disease [1]. Sow herd immunization is a common practice. Vaccinating the sow herd against swine influenza can induce and maintain sufficient immunity in sows and produce passive immunity that is transferred to young pigs during nursing [16-19]. Another approach to SIV control is piglet immunization in the nursery or finisher to provide protection through the finishing period. This strategy helps control SIV-induced disease in growing pigs and will contribute to reducing its impact in PRDC. Current commercial SIV vaccines consist of inactivated viruses combined with adjuvant preparations. The efficacy of these vaccines is primarily through antibody production induced by the vaccine strains whose antigenic make-up is representative of the circulating field strains [20].