Emergence of CD134 cysteine-rich domain 2 (CRD2)-independent strains of feline immunodeficiency virus (FIV) is associated with disease progression in naturally infected cats

Table 1 Mode of CD134 utilisation displayed by 287 Envs from 39 cats

Cat	Alive/Dead	Health status	CD4 count	Mode of CD134 interaction			No. of Envs tested	Homologous neutralisation
Cat	Alive/Dead	Health status	CD4 count	CRD2-dependent	CRD2-independent	Intermediate	No. of Envs tested	Homologous neutralisation
M28	A	H	> 350	11 (100%)	0	0	11	-
M47	A	H	< 350	8 (100%)	0	0	8	+
M8	A	S	< 350	2 (100%)	0	0	2	-
P9	A	S	< 350	6 (100%)	0	0	6	+
M1	A	H	< 350	4 (100%)	0	0	4	-
M2	A	H	> 350	2 (100%)	0	0	2	+
M29	A	H	> 350	3 (100%)	0	0	3	-
P1	A	H	> 350	3 (100%)	0	0	3	-
P11	A	H	> 350	7 (100%)	0	0	7	+
P14	A	H	> 350	9 (100%)	0	0	9	+
P18	A	H	> 350	1 (100%)	0	0	1	+
P21	A	H	> 350	6 (100%)	0	0	6	-
P22	A	H	> 350	2 (100%)	0	0	2	+
P4	A	H	< 350	4 (44.4%)	2 (22.2%)	3 (33.3%)	9	+
P5	A	H	< 350	7 (87.5%)	1 (12.5%)	0	8	+
P6	A	H	> 350	8 (100%)	0	0	8	-
M15	A	S	> 350	6 (66.6%)	3 (33.3%)	0	9	+
M20	A	S	> 350	1 (100%)	0	0	1	-
M32	A	S	< 350	3 (75%)	1 (25%)	0	4	-
P13	A	S	< 350	8 (88.9%)	1 (11.1%)	0	9	+
P17	A	S	< 350	9 (100%)	0	0	9	-
P7	A	S	> 350	1 (50%)	0	1 (50%)	2	+
P8	A	S	> 350	5 (100%)	0	0	5	-
M25	D	H	< 350	3 (50%)	2 (33.3%)	1 (16.7%)	6	+
M46	D	H	< 350	7 (87.5%)	1 (12.5%)	0	8	+
M49	D	H	< 350	6 (100%)	0	0	6	+
M14	D	S	< 350	9 (90%)	1 (10%)	0	10	+
M26	D	S	< 350	4 (66.7%)	2 (33.3%)	0	6	+
M30	D	S	< 350	15 (94%)	1 (6%)	0	16	+
M33	D	S	< 350	2 (11%)	17 (89%)	0	19	-
M41	D	S	< 350	9 (75%)	2 (17%)	1 (8%)	12	-
M5	D	S	< 350	5 (55.6%)	3 (33.3%)	1 (11.1%)	9	-
M11	D	H	> 350	17 (81%)	3 (14%)	1 (5%)	21	-
M50	D	H	> 350	2 (100%)	0	0	2	-
P2	D	H	> 350	16 (100%)	0	0	16	+
M16	D	S	> 350	0	1 (14.3%)	6 (85.7%)	7	-
M3	D	S	< 350	0	1 (50%)	1 (50%)	2	-
M31	D	S	< 350	9 (53%)	7 (41%)	1 (6%)	17	+
M44	D	S	> 350	2 (100%)	0	0	2	+

Cats were classified according to their clinical status at the time of enrolment (H = clinically healthy, S = sick), CD4⁺ cell counts (< or >350 cells/μl) and survival during the study period (A = alive, D = deceased). For absolute CD4⁺ T cell counts see Additional file 2 [Table S2]. Mode of CD134 interaction: numbers (and percentages) of Envs classified as: 1) CRD2-dependent; 2) CRD2-independent; 3) intermediate requirement for determinants within CRD2. For homologous neutralisation, “+” and “-” indicate ≥ or <2.5 fold neutralisation, respectively. For complete neutralisation data see Additional file 3 [Table S3].

ISSN: 1742-4690