TABLE 3.

Histologic scoring of lung sections from rabbits 5 weeks after aerosol infection with M. tuberculosis Erdman^c

Parameter	Rabbit group		Pa
	Inbred	Outbred
Granuloma area (mm2)	2.8 ± 0.2	1.8 ± 0.2	0.020
% with caseous necrosis	89 ± 3	60 ± 11	0.045
Area of necrosis (mm2)	2.6 ± 0.5	0.6 ± 0.2	0.004
Neutrophil scored	2.2 ± 0.3	1.7 ± 0.4	NS
% of mature epithelioid cells (macrophages)	58 ± 5	72 ± 3	0.066
Lymphocytes and plasma cell scored	1.3 ± 0.2	3.7 ± 0.2	0.004
Fibroblast scored	2.8 ± 0.5	1.8 ± 0.4	NS
Perigranuloma pneumonitis scored	3.2 ± 0.3	1.2 ± 0.2	0.005
No. of AFB/mm2 of caseumb	1.04 ± 0.40	0.43 ± 0.15	0.010

^aP values were determined by Mann-Whitney U nonparametric comparison. NS, not significant.

^bAcid-fast bacilli (AFB) per square millimeter of caseous lung tissue were counted in three representative tubercles from each rabbit.

^cData for six rabbits from each group from the experiment described in Table 1 are presented.

^dScored from 1+ to 4+; see text for details.