Summary of serological responses of sera sampled monthly or bimonthly after inoculation from experimentally M. bovis-infected calves in an EIA, ICGA, or LBAA utilizing rMPB70 or ESAT6-p as the capture or conjugating antigen

Sample dateaESAT6-prMPB70
Value for groupb:TotalcValue for groupb:TotalValue for groupb:TotalValue for groupb:TotalValue for groupb:Total
2 wks (−)00000/20 (0)00000/20 (0)00000/20 (0)00000/20 (0)00000/20 (0)
27 days (+)344314/20 (70)245516/20 (80)01012/20 (10)251311/20 (55)03036/20 (30)
78 days (+)20024/20 (20)454518/20 (90)04048/20 (40)252514/20 (70)152513/20 (65)
137 days (+)30036/20 (30)50038/20 (40)452516/20 (80)354517/20 (85)553518/20 (90)
  • a (−), preinfection; (+), postinfection.

  • b Experimental M. bovis infection of 20 calves (5 calves in each of four groups) was carried out by aerosol challenge of 103 (group a) or 105 (group b) CFU of M. bovis from white-tailed deer (1315) or 103 (group c) or 105 (group d) CFU of M. bovis from cattle (HC2005T) (40). Values are numbers of positive sera.

  • c Values are numbers of positive sera/numbers of sera tested, with percent sensitivity in parentheses. ESAT6-p shows a positive reaction with sera collected in the earlier months, but rMPB70 detects positive sera collected in the later months. CMI to M. bovis tuberculin was checked by a skin test with aerosol-infected calves at 57 and 123 days postchallenge with M. bovis (40). As in other studies (27, 28), those skin tests gave a positive effect on the titer of antibody to rMPB70 but not ESAT6-p in blood samples taken 2 and 3 weeks following the skin test.