Table 1.

Days to engorgement and engorgement weight of Ixodes scapularis nymphs fed on B6 and HLA DR3 tg mice during repeated infestations prior to pathogen challenge. Data are expressed as mean ± SD. Figures in parentheses are minimum and maximum values. Statistical significance (P < 0.05) when compared to HLA DR3 primary infestation data is denoted by *

	Engorgement period (days)		Engorgement weight (mgs)
Infestation	B6	HLA DR3	B6	HLA DR3
1st	3.9 ± 0.4	3.5 ± 0.8	3.2 ± 1.1	3.8 ± 1.0
	(3.0–4.0)	(1.0–5.0)	(2.1–5.3)	(2.3–6.1)
	n = 21	n = 35	n = 21	n = 35
2nd	4.1 ± 0.5	4.2 ± 0.9	3.1 ± 1.5	3.4 ± 1.3
	(3.0–5.0)	(3.0–6.0)	(0.4–6.0)	(1.1–5.5)
	n = 31	n = 36	n = 31	n = 36
3rd	4.1 ± 0.5	4.2 ± 0.8	3.5 ± 1.0	3.3 ± 1.1
	(3.0–5.0)	(3.0–6.0)	(2.1–5.9)	(1.2–4.7)
	n = 32	n = 37 *	n = 32	n = 37
	Engorgement period (days)		Engorgement weight (mgs)
Borrelia challenge: tick-bite exposure	B6	HLA DR3	B6	HLA DR3
Naïve	4.1 ± 1.1	4.1 ± 1.1	3.3 ± 1.7	3.8 ± 1.4
	(1.0–6.0)	(1.0–6.0)	(0.3–5.5)	(0.3–5.6)
	n = 36	n = 36	n = 29	n = 36
Sensitized	3.8 ± 0.7	3.8 ± 0.7	3.8 ± 1.3	3.6 ± 1.2
	(3.0–6.0)	(3.0–6.0)	(1.5–5.9)	(2.0–5.6)
	n = 28	n = 28	n = 26	n = 28