Table 2. Cytotoxic capacity of jejunal intraepithelial and lamina propria T-lymphocyte subtypes as determined by an anti-CD3-mediated redirected cytotoxicity assay.

Source and type of effector cells*	Cytotoxic capacity† (LU(20%)/106 cells)	P‡
Epithelium
Total IEL	13·8±1·3§
″IEL depleted of TCR-γδ+ cells	13·4±2·3	NS
″IEL depleted of CD4+ cells	10·1±1·6	NS
″IEL depleted of CD8+ cells	0·9±0·4	0·001
Lamina propria
Total LPL	12·1±2·4
″LPL depleted of TCR-γδ+ cells	10·6±1·5	NS
″LPL depleted of CD4+ cells	4·5±2·1	0·07
″LPL depleted of CD8+ cells	0·8±1·6	0·02

^*Freshly isolated IEL and LPL as well as IEL and LPL depleted of the T-cell subtype indicated were pretreated with anti-CD3 and cytotoxicity measured in a 4-hr⁵¹ Cr-release assay using P815 cells as targets.

^†Cytotoxic capacity was estimated as lytic units (LU)_(20%)/10⁶ cells calculated from the number of effector cells needed to lyse 20% of the target cells.

^‡P-value obtained in statistical analyses using two-tailed Student's t-test comparing effector cells depleted of the indicated T-cell subtype with total IEL or LPL population, respectively. NS, not statistically significant.

^§Mean±SEM LU_(20%)/10⁶ cells of three independent experiments.