Table 2. Effect of treatment with lymphotoxin β-receptor immunoglobulin (LTβR-Ig) on the accumulation of scrapie infectivity in the draining inguinal lymph node 70 days after inoculation with scrapie via the skin^†.

	hu-Ig			LTβR-Ig
Day of treatment	Incidence‡	Mean incubation period (days) ± SE	Titre§	Incidence	Mean incubation period (days) ± SE	Titre
−3	7/7	196 ± 5	6·6	0/9	9× > 300	< 3·5
+14	7/7	193 ± 6	6·7	8/9	217 ± 3*	5·5
+42	8/8	203 ± 4	6·3	6/8	249 ± 4**	4·1

^†Mice were given a single intraperitoneal (i.p.) injection (100 µg) of LT β R-Ig or polyclonal human immunoglobulin G (hu-Ig) as a control on the days indicated before or after inoculation with scrapie via skin scarification of the right thigh. Inginal lymph nodes draining the site of inoculation were pooled from two mice and infectivity levels were determined by intracerebral (i.c.) injection of lysates into groups of C57BL/Dk indicator mice.

^‡Incidence = number of animals affected/number of animals tested. The notation ‘n × > 300’ means that mice were free of the signs of scrapie up to at least this time-point after inoculation.

^§Scrapie infectivity titres expressed as log i.c. 50% infectious dose (ID₅₀)/g.

^*P < 0·01, when compared to the mean incubation period for hu-Ig control tissues.

^**P < 0·001, when compared to the mean incubation period for hu-Ig control tissues.