Relationship of Virulence Factor Expression to Evolved Virulence in Mouse-Passaged Cryptococcus neoformans Lines

DOI: 10.1128/IAI.73.10.7047-7050.2005

Article Figures & Data

Open in new tab
Download powerpoint
FIG. 1.
Correlation between capsule size and passage time to death. Points are the average in vitro capsule size of each line plotted against passage time to death. Strain names indicate the MHC genotype or strain of mice in which C. neoformans was passaged (19).

TABLE 1.

Correlation analysis for virulence factors and C. neoformans strains

C. neoformans strain or parameter^a	Time to death (days)	Ordinal melanin^b (day 7)	Laccase (OD, 420 nm)	Capsule size (μm³)			Doubling time (h)	Phospholipase index^c	Urease (OD, 560 nm)	Phagocytosis index in J774.16 cells^d	Macrophage killing^e	GXM released in vitro (μg/ml)
C. neoformans strain or parameter^a	Time to death (days)	Ordinal melanin^b (day 7)	Laccase (OD, 420 nm)	In vitro	Liver	Brain	Doubling time (h)	Phospholipase index^c	Urease (OD, 560 nm)	Phagocytosis index in J774.16 cells^d	Macrophage killing^e	GXM released in vitro (μg/ml)
D1	41	4	0.2	870	NA	NA	2.6	0.5	0.1	1.1	2.3	5.1
H99	39	0	0.2	1,200	NA	NA	3.0	0.6	0.2	0.9	9.0	1.9
F1	39	4	0.2	1,900	390	360	3.2	0.6	0.1	0.7	2.8	8.1
B1	32	2	0.2	270	760	1,200	3.7	0.6	0.1	1.5	13	26
K2	31	2	0.3	520	1,600	660	3.1	0.6	0.1	1.1	1.0	11
F2	26	0	0.2	630	320	320	3.2	0.5	0.2	0.8	5.3	15
B2	25	0	0.2	680	620	780	3.2	0.6	0.1	1.3	18	10
K1	24	3	0.2	850	1,300	2,200	2.8	0.7	0.2	1.0	1.0	11
Q2	22	0	0.2	380	440	560	3.0	0.5	0.0	1.4	2.0	0.1
Balb1	15	3	0.3	240	630	640	3.2	0.6	0.0	1.1	1.8	1.7
Alt d/q	14	0	0.3	350	360	460	3.6	0.6	0.2	0.6	2.8	46
Q1	13	2	0.2	660	1,300	1,200	3.4	0.6	0.1	1.1	1.5	6.0
D2	7	0	0.2	750	1,100	1,400	2.6	0.6	0.1	1.3	3.5	16
Balb2	7	2	0.2	250	220	730	3.3	0.6	0.2	0.8	4.3	3.8
Alt het	6	0	0.2	430	970	840	3.3	0.6	0.1	0.7	2.5	12
Control strains
H99D	14	0	0.2	1,000	1,600	980	2.9	0.5	0.1	1.2	11	26
H99E	NA^f	2	0.3	2,700	NA	NA	2.4	0.6	0.1	2.9	19	2.0
24067	NA	3	0.2	1,300	NA	NA	2.7	1.0	0.0	3.1	19	4.1
R² with time to death		0.17	0.01	0.28 ^g	0.01	0.03	0.03	0.03	0.04	0.01	0.02	0.04
P value		0.11	0.80	0.03	0.81	0.58	0.52	0.53	0.48	0.67	0.57	0.45

↵ a Strain names reflect the major histocompatibility complex genotypes or strains of mice in which C. neoformans was passaged (19). Strains H99Duke (H99D), H99Einstein (H99E), and 24067 are controls. AH d/q indicates C. neoformans passaged in alternating d/d and g/g MHC genotypes. Alt het indicates C. neoformans passaged in alternating heterozygote MHC genotypes. H99 is the nonpassaged C. neoformans strain.
↵ b 0, no color; 1, absence or presence of color; 2, some color; 3, moderate amount of color; 4, a lot of color.
↵ c Ratio of the colony diameter to the diameter of the colony plus the precipitation zone.
↵ d Ratio of macrophages associated with C. neoformans to the total number of macrophages counted.
↵ e Number of dead macrophages at 18 h.
↵ f NA, not available.
↵ g Boldface indicates significant correlation.