Submitted to: Porcine Reproductive and Respiratory Syndrome International Symposium
Publication Type: Proceedings
Publication Acceptance Date: October 1, 2006
Publication Date: December 1, 2006
Citation: Mccaw, M.B., Lunney, J.K., Tompkins, W. 2006. Increased viremia, altered immune responses, fever, and pathologic lesions following intranasal heterologous wild-type PRRSV challenge: Identification of markers associated with incomplete cross-protection in respiratory disease model [Abstract]. Proceedings 2006 International PRRS Symp. Abstract 10, p. 22. Available: http://www.prrssymposium.org/Documents/2006%20International%20PRRS%20Symposium%20-%20Proceedings.pdf
Objective: Investigate immune response differences associated with inadequate cross-protection against heterologous WT-PRRSv challenge in a respiratory disease model. ATTC 2332 was used to IN infect 10 Medicated Early Weaned pigs at 4 weeks of age and five pigs each were then IN challenged 6 weeks later with ATTC 2332 or heterologous WT NCPowell PRRSv, respectively. Serum and temperatures were collected regularly, PMBCs at 21 days PC, and bronchial lymph nodes and lung tissue at 24 days PC. Lymphocytes and PBMC’s were stimulated in vitro with homologous or heterologous LV or KV, supernatants and cell pellets collected for cytokine ELISA and quantitative RTPCR respectively. Significantly increased and prolonged group mean fever, viremia, percent pneumonia, and enlarged mediastinal LN were found in NCPowell WT PRRSv-challenged vs homologous virus challenged pigs. Differences were also noted in virus-specific SN titers and ELISA antibody response curves post-challenge. In vitro stimulation cytokine responses are currently being determined. Immune responses generated following VR2332 infection were inadequate to cross-protect against NCPowell WT PRRSv challenge 6 weeks later. Post-challenge antibody responses were different.