TABLE 1.

Microglial and neuronal association and internalization of M. tuberculosis bacilli^a

Cell type	Bacillus/cell ratio	% cell associated			% internalized		Ratio (% internalized/% cell associated)
		6 h	24 h	48 h	24 h	48 h	24 h	48 h
BV2	2:1	2.1 ± 0.92	31.1 ± 1.84	34.6 ± 4.79	31.0 ± 4.20	34.7 ± 2.50	1.00	1.00
Primary microglia	2:1	6.5 ± 2.23	31.5 ± 5.83	32.5 ± 0.86	30.8 ± 6.30	32.1 ± 6.56	0.98	0.99
HT22	30:1	6.7 ± 1.65	17.2 ± 9.74	28.9 ± 1.00	11.8 ± 1.83	17.7 ± 1.34	0.68	0.61
Neuro-2a	30:1	1.9 ± 0.45	6.1 ± 4.03	20.0 ± 0.72	6.2 ± 1.41	9.8 ± 1.97	1.00	0.49
Primary neurons	30:1	7.9 ± 1.64	13.6 ± 3.30	21.3 ± 0.46	11.2 ± 0.89	10.1 ± 2.07	0.82	0.48
SK-N-SH	30:1	10.2 ± 1.47	17.9 ± 2.65	21.0 ± 2.41	11.9 ± 1.72	18.5 ± 1.18	0.67	0.88

^aMicroglia and neurons were infected with M. tuberculosis, and cells that were associated with or had internalized bacilli at 6 h, 24 h, and 48 h were counted. The results represent the means ± SD of the combined data from at least 3 individual experiments.