Table 1.

Conjugation of BP to cytokines relative to IFN-γ

		Amino acid residues per molecule		Relative band intensity
Cytokine	MW	Lysine	Histidine	Leading bandMean ± SD Lysine	TotalMean ± SD Histidine
IFN-γ	16·7	20	2	1	1
IL-1β	17	15	1	0·82 ± 0·06	0·66 ± 0·15
IL-2	15·4	11	3	0·21 ± 0·59	0·59 ± 0·33
IL-4	14·9	12	5	0·05 ± 0·05	0·06 ± 0·05
IL-5*	25	16	6	0·68 ± 0·11	1·03 ± 0·14
IL-10	18·6	13	3	0	0
IL-13	12·5	7	3	0·67 ± 0·16	0·51 ± 0·14
TNF-α	17·4	6	3	0·66 ± 0·14	0·46 ± 0·09
mIFN-γ	15·6	10	3	0·24 ± 0·27	0·16 ± 0·19

Cytokines were incubated at 10 µg/ml with or without 5 mg/ml of BP in PBS. After overnight incubation at 37°C, samples were analysed by SDS-PAGE and Western blotted with rabbit polyclonal anti-BP antibody. IFN-γ was included as an internal reference in all experiments and other cytokines were related to IFN-γ as a ratio of band intensity, following densitometric analysis. Ratios of test cytokine to IFN-γ were calculated for monomer bands (determined from molecular weight) and for the total intensity of all bands in each lane. Results represent the mean ± standard deviation of three experiments. MW, molecular weight in kD. m, murine.

^*dimer, see text and [ 10].