TABLE 5.

Nitric oxide responses to crude mycobacterial antigens upon experimental infection

Infection statusNO responsea to recall antigen (WCS):
M. bovis strain 1315M. avium strain 3988M. avium subsp. paratuberculosis strain K10
Noninfected−106 (53) A−49 (51) A−63 (43) A
M. bovis-infected451b (46) C184 (21) B97 (35) AB
M. avium-infected79 (17) B185b (20) B55 (14) AB
M. avium subsp. paratuberculosis-infected87 (52) AB213 (61) B278 (117) B
  • a NO responses by PBMC were unaffected (P > 0.05) by the length of postinfection period. For this reason, values are the mean NO responses (in nanograms per milliliter) (i.e., response to 20 μg of antigen per ml minus their response to medium alone after 72 h) during the period spanning 5 to 7 months postinfection. Treatment groups consisted of four animals except for the M. avium subsp. paratuberculosis-infected group, which had three animals. Values in parentheses are the standard errors of the means.

  • a Letters A to C indicate that the treatment means for a specific type of stimulation (i.e., vertical comparisons) differ (P < 0.05). The same letter indicates that the NO responses were not significantly different (P < 0.05).

  • b Significantly different from the responses by the other cattle infected with M. bovis or M. avium (i.e., horizontal comparisons) (P < 0.05).