About

Renukaradhya Gourapura, DVM, PhD, is a Professor and Director of the Center for Food Animal Health at The Ohio State University. He holds degrees from the Indian Institute of Science in Bangalore, including a PhD obtained in 2002, an MVSc (MS) from the University of Agricultural Sciences in Bangalore, and a BVSc (DVM) from the same university. His research focuses on mucosal immunology in food animals infected with infectious and zoonotic diseases, with particular attention to mucosal delivery of vaccines to improve cross-protective immunity against RNA viruses and mucosal pathogens. Dr. Gourapura's laboratory develops innovative biodegradable and biocompatible polymer-based nanoparticle vaccine delivery platforms aimed at efficiently targeting vaccine antigens to immune cells at mucosal sites. His work involves understanding immune correlates of protection and efficacy following viral or bacterial challenge infections in animals vaccinated via intranasal and oral routes. His research includes improving the efficacy of inactivated whole pathogen and subunit vaccines for influenza virus and porcine reproductive and respiratory syndrome virus, as well as evaluating immune modulators, bacterial-based and synthetic adjuvants, and different polymers-based vaccine carriers targeting toll-like receptors in mucosal immune sites of food animals and poultry. Currently, his lab investigates nanoparticle-based SARS-CoV-2 subunit vaccine candidates in ferret and pig models to determine their efficacy and immunogenicity. Broadly, his research encompasses understanding host-pathogen interactions, microbial pathogenesis, developing pig models to study the influence of the human microbiome on vaccines and diseases, and elucidating immune evasion mechanisms in food animals infected with viral and bacterial pathogens. Additionally, Dr. Gourapura is involved in developing large animal models for biomedical and preclinical research to improve human health. He leads a collaborative team of scientists at USDA research facilities and CFAH, focusing on developing new swine immune reagents and evaluating their functional and phenotypic properties.

Selected publications

• Relative Accuracy of Diagnostic Methods in Verification of Gonadal Status of Dogs Considering Anti-Mullarian Hormone as a Biomarker

  International Journal of Animal Biotechnology and Applications · 2025-01-01

  articleOpen access

  The study was carried out to demonstrate relative efficacy of various methods to ascertain gonadal status in dogs.Based on different diagnostic methods viz., history and clinical signs, physical examination and ultrasonography, 37 (21 male and 16 female) dogs were categorised into different groups.Group I-gonadectomised dogs (n=10; Male-5 Female-5), Group II -intact dogs before and after gonadectomy (n=16; Male-8 Female-8), Group III-dogs with ovarian remnant syndrome (ORS) (n=3) and Group IV-dogs with either unilateral/ bilateral cryptorchidism (n=8).All the dogs were subjected to serum Anti-mullarian hormone (AMH) estimation using canine specific AMH kits.The mean AMH level in intact male dogs, castrated and cryptorchid dogs was 16.20 1.44, 0.57 0.06 and 24.90 0.79 ng/mL, respectively.In female dogs, the mean AMH value was 5.14 0.54, 3.20 1.54 and 0.26 0.02 ng/mL in intact, ORS and spayed dogs, respectively.By considering AMH as the standard to ascertain the gonadal status, the relative accuracy of history and clinical signs was 85.71 and 100%, physical examination was 61.90% and 43.75%, whereas with trans-abdominal ultrasonography 71.42% and 18.75% in male and female dogs, respectively.A single serum AMH concentration measurement was highly effective in accurately distinguishing between gonadectomized and intact adult dogs.In addition, this test also accurately identified several cases of ovarian remnant syndrome and cryptorchidism which were failed to identify using other methods.

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• Evaluation of mucosal adjuvants to chitosan-nanoparticle-based oral subunit vaccine for controlling salmonellosis in broilers

  Frontiers in Immunology · 2025-02-03 · 8 citations

  articleOpen accessSenior authorCorresponding

  Salmonellosis, a gastrointestinal disease, continues to be one of the major public health concerns worldwide. Poultry meat and eggs are recognized as the major source of Salmonella food poisoning in humans. Our study evaluated the protective efficacy of mannose-conjugated chitosan-nanoparticle (mChitosan-NP)-based subunit vaccine, consisting of immunogenic outer membrane proteins and flagella of Salmonella Enteritidis [mChitosan (OMP+FLA)/FLA-NP], coadministered orally with potent mucosal adjuvants to reduce the colonization of S. Enteritidis in the intestines of broiler chickens. We evaluated the adjuvant effects of three different doses of two well-known mucosal adjuvants, c-di-GMP (stimulator of interferon gene agonist) and whole cell lysate (WCL) of Mycobacterium smegmatis , to improve the efficacy of mChitosan (OMP+FLA)/FLA-NP vaccine. Our data reaffirmed the potent adjuvanticity of both of these adjuvants and identified their optimal dose when entrapped in mChitosan-NP to potentiate the immunogenicity and efficacy of orally delivered mChitosan (OMP+FLA)/FLA-NP vaccine. The physical characteristics of mChitosan (OMP+FLA)/FLA-NP, mChitosan-GMP/FLA-NP, and mChitosan-WCL/FLA-NP formulations revealed a high positive charge (Zeta potential +20–25 mV), size 235–260 nm, and polydispersity index 0.35–0.52, which are conducive for oral delivery. The efficacy in chickens that received oral administration with a combination of the vaccine-adjuvant formulations was evaluated by challenging with Salmonella Enteritidis. Our data showed that mChitosan (OMP+FLA)/FLA-NP WCL at 10 µg/dose formulation consistently reduced the S. Enteritidis load by over 0.5 log 10 comparable to a commercial live vaccine at post-challenge days 4 and 10. Immunologically, we observed enhanced systemic and mucosal antibody and cellular (B cells and T-helper cells) immune responses as well as upregulation of expression of immune cytokine genes IFN-γ, TGF-β, and IL-17 in the cecal tonsils of adjuvanted mChitosan-NP Salmonella -subunit-vaccinated birds. Overall, particularly the mucosal adjuvant WCL consistently enhanced the efficacy of mChitosan (OMP+FLA)/FLA-NP vaccine by inducing effective immune responses.

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• Influenza-specific antibody-mediated and complement-dependent cellular cytotoxicity-inducing antibodies in vaccinated and infected pigs

  Frontiers in Immunology · 2025-06-30

  articleOpen accessSenior authorCorresponding

  In addition to neutralizing activity, antibodies can contribute to protection against viral infections through antibody-dependent cellular cytotoxicity (ADCC) and antibody-mediated complement-dependent cell cytotoxicity (CDC) mediated via Fcy receptors. Swine is a suitable large-animal biomedical model for influenza research, because it is a natural host for influenza like humans exhibiting comparable clinical and immunological responses. Unfortunately, there are currently limited insights into ADCC and CDC functions to swine influenza A virus (SwIAV) in pigs due to lack of adequate immunological tools. Therefore, the present study was aimed at optimizing the ADCC and CDC assays to evaluate the cytotoxicity mediated by virus-specific antibodies in response to vaccination of pigs with chitosan nanoparticle-based inactivated monovalent and commercial multivalent SwIAV vaccines administered through intranasal and intramuscular route, respectively. Using these assays, we quantified and compared the antibody-mediated cytotoxicity induced in pigs by intranasal chitosan nanoparticle-based inactivated monovalent whole SwIAV vaccine and intramuscular administered commercial multivalent SwIAV vaccine. Our results revealed that maternal antibody-positive pigs following vaccination with whole inactivated virus failed to elicit specific ADCC-mediating antibodies, but production of CDC antibodies was not affected. However, after exposure of vaccinated animals to challenge infection, high levels of ADCC antibodies were elicited. Further, it was observed that the function of virus-specific neutralizing and non-neutralizing antibodies are influenced by route of vaccination (intranasal versus intramuscular), vaccine type (monovalent versus multivalent) and adjuvant formulation. Overall, we observed a positive trend among the magnitude of ADCC, CDC, antibody avidity, Nabs, and HA inhibition (HAI) antibody responses in vaccinated and influenza virus-infected pigs. In conclusion, measuring ADCC- and CDC-mediating antibodies in pigs is important for evaluating the protective immunity against influenza by vaccines. Monitoring the function of both virus-neutralizing and non-neutralizing antibodies in vaccinated animals aid in the development of innovative cross-protective vaccine formulations to fight against constantly evolving influenza viruses.

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• Concurrent but consecutive vaccination of modified live PRRSV-1 and PRRSV-2 provides better protection in nursery pigs

  Veterinary Microbiology · 2025-01-13 · 2 citations

  articleOpen accessSenior authorCorresponding

  Porcine reproductive and respiratory syndrome (PRRS) virus is a severe threat to the global swine industry. Modified live virus vaccines (MLVs) for two PRRSV species (PRRSV-1 and PRRSV-2) are the most widely used approach to control PRRSV-caused diseases. For swine herds influenced by PRRSV-1 and PRRSV-2, how to rationalize MLV immunization strategies for robust and cross-protective immune responses has been a long-lasting need. In this study, we found that the replication of PRRSV-1 is strongly suppressed by co-infection with PRRSV-2 in vitro , especially under concurrent co-infection conditions. We compared the adaptive immune responses between consecutive and concurrent vaccination methods in nursery pigs, vaccinated either 3 days apart (PRRSV-1 MLV followed by PRRSV-2 MLV, consecutive) or together on the same day (concurrent). PRRSV-1 RNAs were mainly detectable in the sera of consecutively vaccinated pigs. In contrast, PRRSV-2 RNAs in sera were not changed in both vaccination strategies. After the homologous PRRSV-1 or PRRSV-2 challenge, we found that consecutive vaccination slightly improved PRRSV-1 viremia clearance and did not attenuate the PRRSV-2 viremia clearance. Both vaccination strategies induced comparable T-helper cell responses against PRRSV-1 and PRRSV-2 in peripheral blood before and after the challenge. Interestingly, consecutive vaccination induced significantly higher PRRSV-1-specific post-challenge T-helper and cytotoxic T cells responses in the tracheobronchial lymph nodes than concurrent vaccination. Furthermore, consecutive vaccination significantly improved neutralizing antibody responses against PRRSV-1 and PRRSV-2 in comparison with concurrent vaccination. In conclusion, consecutive vaccination appears to be better for viral clearance and induction of adaptive immune response, and our study provides a preliminary rationale to optimize PRRS MLV immunization strategy for better dual protection. • Replication of PRRSV-1 is strongly suppressed by co-infection with PRRSV-2 in vitro . • Vaccination strategies for two PRRSV species wereanalyzed in a nursery pig challenge model. • Concurrent MLV vaccination failed to protect pigs against PRRSV-1 but it performed comparably to consecutive vaccination against PRRSV-2. • Consecutive MLV immunization (PRRSV-1 followed by PRRSV-2) provided better protection protection against both species of PRRSV infection.

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• Evaluation of safety, immunogenicity, and efficacy of inactivated reverse-genetics-based H5N8 highly pathogenic avian influenza virus vaccine with various adjuvants via parenteral and mucosal routes in chickens

  Frontiers in Immunology · 2025-03-20 · 5 citations

  articleOpen access

  Background: Highly pathogenic H5Nx avian influenza (HPAI) poses a significant threat to poultry health globally, necessitating the development of effective vaccination strategies. Methods: This study assessed the immunogenicity and efficacy of a reverse-genetics-derived, Differentiating Infected from Vaccinated Animals (DIVA)-compatible inactivated H5N8 vaccine based on the IDCDC-RG71A strain. The vaccine was formulated with different adjuvants, including Montanide ISA 78 VG, ISA 71 R VG, GEL P PR, and mannose-conjugated chitosan nanoparticles, and administered via either the subcutaneous (SC) or intranasal (IN) route. To evaluate safety, the vaccine was tested in specific antibody negative (SAN) chickens, showing no adverse effects. Immunogenicity was assessed by measuring hemagglutination inhibition (HI) antibody titers, antigen-specific IgA and IgY levels, and CD4+ and CD8+ T cell proliferation. Vaccine efficacy was determined through a challenge study using a field isolate of H5N1. Results: This showed that a single SC dose of vaccine containing ISA 78 VG or ISA 71 R VG provided the best efficacy against infection, with high survival rates, control of abnormally high temperature incidence, reduced virus shedding, and reduced lung and liver lesions. The ISA 78 VG-adjuvanted SC vaccine induced the highest HI titers and CD4+ T cell proliferation, while ISA 71 R VG and GEL P PR elicited the strongest IgY responses. In contrast, IN formulations induced IgA in the lungs and trachea however, even after two doses, failed to generate high HI titers and provided poor, if any, protection against infection. This highlights the superior efficacy of the SC over the IN route of vaccination for reducing H5N1 viral shedding. Conclusion: These results underscore the importance of both the adjuvants and delivery route to maximize HPAI vaccine efficacy. This presented system could thereby be used to develop potent and DIVA-compatible vaccines to enhance biosecurity and disease management in regions affected by endemic HPAI.

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• Haematological, biochemical, histopathological studies and isolation of bacteriological agents from canine pyoderma cases in Karnataka

  Indian Journal of Animal Health · 2024-06-01

  articleOpen accessSenior author

  The present study was carried out to investigate the haematology, serum biochemistry, histopathology and isolation of causative bacterial agents from canine pyoderma cases.The highest occurrence of canine pyoderma was recorded in the age group between one to six years and particularly in male dogs.Affected dogs showed significant (P < 0.05) decrease in the haematological values like haemoglobin, total erythrocyte count and significant increase in the total leucocytes, absolute neutrophil and eosinophil counts.Reduced albumin, increased cholesterol levels in serum biochemistry and infiltration of neutrophils with nuclear debris in the superficial keratin layer of the epidermis in histopathological analysis were recorded in pyoderma-affected dogs.Forty bacterial isolates were identified as S. intermedius (n=17), S. schleiferi (n=10), S. aureus (n=5), P. aeruginosa (n=5) and E. coli (n=3) based on cultural and biochemical characters.The study was concluded with significant changes in haematological, serum biochemical parameters and isolation of S. intermedius from canine pyoderma cases as a major bacteriological agent.

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• MEDICAL MANAGEMENT OF TYPE 1 VAGINAL HYPERPLASIA IN BITCHES WITH GnRH

  Indian Journal of Canine Practice · 2024-12-26

  articleOpen accessSenior author

  A Pug breed dog aged three years, weighing 9.9 kg and gave birth once was brought to the Department of Veterinary Gynaecology and Obstetrics,Veterinary College, Gadag, with a history of small deep pink color protrusion in between the vulval lips since a few days and shows estrus related behaviour in this cycle.On detailed clinical examination of vagina mass found a type I vaginal prolapsed was observed.Further, the vaginal cytology confirmed estrum with more than 80 % superficial and cornified cells.All other vital parameters were within normal range.The dog was injected with synthetic GnRH @2.2 mg/Kg body weight (4.7ml) each ml of Gynarich (containing 4ug/ml subcutaneously) is used for an ovulated follicle or cyst which results in high estrogen level predisposing to vaginal oedema and prolapse.After 5 th day of the treatment, the prolapsed mass completely disappeared

  PublisherDOI

• Diagnosis and surgical treatment of right paramedian hepatoid gland tumour in dog

  JIVA · 2024-12-01

  articleOpen access
  PublisherDOI

• Incidence of canine reproductive cases presented to veterinary college Gadag, during 2021-2023

  INTERNATIONAL JOURNAL OF AGRICULTURAL SCIENCES · 2024-01-15

  articleOpen access

  A study on the incidence of gynaecological cases in canines was presented between April 2021andMarch 2023 at the Department of Veterinary Gynaecology and Obstetrics, Veterinary College Gadag. A total of 374 gynaecological cases were presented. The highest incidence was found to be Exfoliative Vaginal Cytology (36.10%), followed by Pregnancy Diagnosis (26.74%), Birth control (7.49%), Tumour (7.22%), Assisted mating and AI (7.22%), Pyometra (6.15%), Anoestrous (4.28%), Mismating (2.41%), Dystocia (1.34%) and Retention of Fetal Membranes (1.07%). Breed-wisepredilection indicated that Labrador Retriever(32.89%), Golden Retriever (10.70%), German Shepherd (10.70%), Rottweiler (9.63%) and others(36.10%).The majority of cases were presented during Winter (29.94%), followed by Monsoon (25.94%), Autumn (22.73%) and Summer (21.39%).

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• MEDICAL MANAGEMENT OF POST-PARTUM HYPOCALCEMIC ALLIED HYPOKALEMIC ALERT DOWNER COW

  JIVA · 2024-04-29

  articleOpen access

  A cross bred cow after fortnights of second calving has presented to the Veterinary Dispensary, Panrutti, Tamilnadu with the history recumbency, voiding habits Based on the systemic therapy response and diagnosis the case of hypocalcemichypokalemic alert downor cow was treated lucratively.

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