Exposure to Mycobacterium avium primes the immune system of calves for vaccination with Mycobacterium bovis BCG

C. J. Howard*, L. S. Kwong, B. Villarreal-Ramos, P. Sopp, J. C. Hope

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Citations (SciVal)


The objective of the investigation was to provide data on how a prior exposure of cattle to Mycobacterium avium, used here as a model of exposure to an environmental mycobacterium, affected the cellular immune response that follows vaccination with Mycobacterium bovis BCG. The assessment of cellular immune responses included lymphocyte proliferation assays, the delayed hypersensitivity skin test and IFN-γ synthesis in whole blood cultures. One group of calves was inoculated subcutaneously with M. avium followed 12 weeks later by M. bovis-BCG. The other group was vaccinated subcutaneously with BCG alone. Calves previously exposed to M. avium responded more rapidly, as assessed in the in vitro assays, to purified protein derivative (PPD) from M. avium (PPD-A) or M. bovis (PPD-B) than did calves inoculated with BCG only, indicating that the exposure to M. avium had primed the immune response in these calves. Following inoculation of BCG the intensity of the in vitro responses and the delayed hypersensitivity skin test to PPD-A was higher for the M. avium-primed animals while the responses to PPD-B were similar in the M. avium-primed and BCG-only groups. The results are consistent with a model in which prior exposure to environmental mycobacteria does not necessarily inhibit the immune response to the vaccine strain, BCG. They suggest that M. avium infection primes the immune system of calves and that the detection of an immune response specific for M. bovis BCG is masked by reactivity to antigens also present in M. avium.

Original languageEnglish
Pages (from-to)190-195
Number of pages6
JournalClinical and Experimental Immunology
Issue number2
Early online date17 Oct 2002
Publication statusPublished - 18 Nov 2002


  • BCG
  • Bovine TB
  • Interferon-γ
  • Mycobacteria
  • Skin test


Dive into the research topics of 'Exposure to Mycobacterium avium primes the immune system of calves for vaccination with Mycobacterium bovis BCG'. Together they form a unique fingerprint.

Cite this