Pharma Investments, Ventures & Law Weekly
March 12, 2006 EXPANDED REPORTING; Pg. 108
IOWA STATE UNIVERSITY
Study investigated porcine reproductive and respiratory syndrome virus
vaccine
Investigators evaluate immune responses and protection by vaccine and various
vaccine adjuvant candidates to virulent porcine reproductive and respiratory
syndrome virus in a recent issue of Veterinary Immunology and
Immunopathology.
"Various vaccine adjuvant candidates were assessed with the modified-live porcine
reproductive and respiratory syndrome virus (MLV PRRSV) (Ingelvac PRRS MLV)
vaccine. Their influence on humoral-mediated immune (HMI) and cell-mediated immune
(CMI) responses as well as protection from virulent PRRSV challenge (MN-184) was
evaluated," researchers in the United States report.
Wasin Charerntantankul and collaborators at Iowa State University and Boehringer
Ingelheim Vetmedica, Inc. wrote, "Ninety seronegative pigs were randomly divided into
nine groups of 10 pigs. One group received MLV vaccine alone. Five groups received
MLV vaccine with either bacterial endotoxin-derived adjuvant (ET), mixed open reading
frame 5 (ORF5) peptides derived from various PRRSV isolates, porcine interferon alpha
(IFN alpha), polyinosinic-polycytidylic acid stabilized with polylysine and carboxymethyl
cellulose (poly-ICLC), or porcine interleukin-12 (IL-12). One group did not receive MLV
vaccine but was immunized with ORF5 peptides conjugated with cholera toxin (ORF5
peptide/CT). Two groups served as challenged and unchallenged nonvaccinated
controls."
Charerntantankul and associates stated, "Four-color flow cytometry was utilized to
simultaneously identify three major porcine T-cell surface markers (CD4, CD8, and
gamma delta TCR) and detect activation marker CD25 (alpha chain of IL-2 receptor) or
intracellular IFN-gamma. The MLV PRRSV vaccine alone successfully primed CD4-
CD8+gamma delta- T-cells as demonstrated by a significant increase in %IFN-gamma+
cells when live PRRSV was used as a recall antigen."
"Booster immunizations of mixed ORF5 peptides and co-administration of IL-12 with
MLV PRRSV vaccine significantly enhanced IFN-gamma expression by some T-cell
subsets (CD4-CD8+gamma delta+ and CD4-CD8-gamma delta+ for mixed ORF5
peptides and CD4+CD8+gamma delta- and CD4-CD8+gamma delta+ for IL-12),"
reported the scientists. "All groups receiving MLV-vaccine with or without adjuvants had
reduced lung lesions after challenge. The group immunized with only ORF5 peptide/CT
did not have significant T-cell recall responses and was not protected from challenge."
"Expression of IFN-gamma by several T-cell subsets correlated with reduced lung
lesions and viremia, whereas expression of CD25 did not," noted the investigators.
"Expression of surface CD25 did not correlate with IFN-gamma production. PRRSV
ELISA s/p ratio prior to challenge also correlated with reduced lung lesions and viremia.
Booster immunizations of the mixed ORF5 peptides and co-administration of IL-12
effectively enhanced the CMI response to MLV vaccine. However, neither adjuvant
significantly contributed to reducing clinical effects when compared to MLV alone."
Charerntantankul and coauthors published their study in Veterinary Immunology and
Immunopathology (Immune responses and protection by vaccine and various vaccine
adjuvant candidates to virulent porcine reproductive and respiratory syndrome virus. Vet
Immunol Immunopathol, 2006;109(1-2):99-115).
For additional information, contact James A. Roth, Department of Veterinary
Microbiology and Preventive Medicine, Iowa State University, College of Veterinary
Medicine, Ames, IA 50011-1250, USA. E-mail: jaroth@iastate.edu.
The publisher of the journal Veterinary Immunology and Immunopathology can be
contacted at: Elsevier Science BV, PO Box 211, 1000 AE Amsterdam, The Netherlands.
Keywords: Ames, Iowa, United States, Virology Vaccine, Vaccine Development, Vaccine
Adjuvant, Vaccine Efficacy, Porcine Reproductive and Respiratory Syndrome Virus,
Immunology, Immunotherapy, Proteomics, Veterinary Medicine.
This article was prepared by Pharma Investments, Ventures & Law Weekly editors from
staff and other reports.