Efficacy of spheroplastic and cell-wall competent vaccines for Mycobacterium avium subsp. paratuberculosis in experimentally-challenged baby goats

Murray E. Hines, Shane Stiver, Dipak Giri, Lisa Whittington, Cindy Watson, Jill Johnson, Julie Musgrove, Mel Pence, David Hurley, Charles Baldwin, Ian Gardner, Sharif S Aly

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

A Mycobacterium avium subspecies paratuberculosis (MAP) vaccine that reduced the incidence of clinical disease or reduced fecal shedding of MAP would aid control of Johne's disease (JD). The objective of the present study was to evaluate the efficacy of four MAP vaccine combinations, including cell-wall competent (CWC) alum adjuvant, CWC-QS21 adjuvant, cell-wall deficient (CWD) alum adjuvant and CWD-QS21 adjuvant vaccines. Eighty baby goats were vaccinated at 1 and 4 weeks of age with one of these vaccines or a sham control vaccine consisting of alum adjuvant. Kids were challenged orally with approximately 6.0 × 109 organisms in four divided doses of 1.5 × 109 organisms using a goat isolate of MAP. Vaccinated challenged and challenged control groups had 10 and 6 kids per group, respectively. Half of the kids within each group were necropsied at either 6 or 9 months post-challenge. Gross and microscopic lesions and relative number of acid-fast bacilli were evaluated and scored at necropsy. Results indicated all challenged kids had some lesions compatible with JD suggesting none of the vaccines prevented infection. Three vaccines (CWC-alum, CWC-QS21 and CWD-QS21) reduced lesion scores by 46-51% at 9 months. CWD-alum vaccine resulted in a more severe (+33.5%) lesion score than sham-vaccinated challenged control. Lesion scores were greater at 9 months than at 6 months post-challenge in the sham-vaccinated challenged group and CWD-alum vaccinated group, while lesion scores were generally stable with remaining vaccines. Mean fecal CFU/g were significantly different across time from challenge to 9-month necropsy (p = 0.043) and the CWC-QS21 vaccine group had a marked reduction in fecal CFU/g at all time points post-challenge. A reduction in MAP CFU/g was also detected in necropsy tissues from kids given the CWC-alum, CWC-QS21 and CWD-QS21 vaccines, and increased CFU/g were detected in tissues from kids given the CWD-alum vaccine. Immunological tests evaluated included, humoral response evaluation by AGID, ELISA and Western blot, and cell mediated response by comparative PPD skin testing (M. avium, Old Johnin, M. bovis and Lot 2 Johnin PPD's), and production of MAP induced γ-interferon. Vaccination also resulted in false-positive PPD skin test reactions for M. avium PPD, Old Johnin PPD and γ-interferon tests. When a 2-mm cutoff above normal skin thickness was used to define positive skin test reactions, false-positive reactions for M. bovis were detected in only 2 of 32 kids given a vaccine with QS21 adjuvant.

Original languageEnglish (US)
Pages (from-to)261-283
Number of pages23
JournalVeterinary Microbiology
Volume120
Issue number3-4
DOIs
StatePublished - Mar 10 2007

Keywords

  • Diagnostic tests
  • Goats
  • Mycobacterium avium subsp. paratuberculosis
  • Vaccine efficacy

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Microbiology
  • veterinary(all)

Fingerprint Dive into the research topics of 'Efficacy of spheroplastic and cell-wall competent vaccines for Mycobacterium avium subsp. paratuberculosis in experimentally-challenged baby goats'. Together they form a unique fingerprint.

  • Cite this