An ultrasensitive system to detect IL-4: enzyme-linked immunosorbent assay (ELISA) combined with an avidin-biotin and enzyme amplification system.
We established an ultrasensitive interleukin-4 enzyme-linked immunosorbent assay by combining ELISA with an avidin-biotin and enzyme amplification system. The resultant system (AB-EA ELISA) was 250 times more sensitive than conventional ELISA and 2.5 times more sensitive than enhanced ELISA using an enzyme amplification system alone. The ultrasensitive assay was specific to IL-4 alone; there was no cross reaction with other cytokines. Using the ultrasensitive assay, we measured IL-4 synthesis in vitro by unstimulated and stimulated peripheral blood mononuclear cells (PBMC) from patients with allergic rhinitis. PBMC from patients spontaneously produced measurable amounts of IL-4, whereas IL-4 production from PBMC of normal controls, if any, was below detectable levels. Stimulation of the cultures with LPS significantly increased IL-4 production in two of six patient PBMC cultures but in none of the control cultures; stimulation with Con A markedly increased IL-4 production in all patient PBMC cultures but in only two of seven control cultures. These results suggest that the AB-EA ELISA is a useful method to study the mechanism of IL-4 synthesis in type-I allergic diseases.
Ishizuka
T
T
Internal Medicine I, National Defense Medical College, Saitama, Japan.
Kawagoe
M
M
Suzuki
K
K
Hara
M
M
Harigai
M
M
Kawakami
M
M
Kawaguchi
Y
Y
Hidaka
T
T
Matsuki
Y
Y
Tanaka
N
N
D000818:Animals; D001360:Avidin; D001710:Biotin; D004797:Enzyme-Linked Immunosorbent Assay; D015847:Interleukin-4 / Q000032:analysis* / Q000096:biosynthesis; D007963:Leukocytes, Mononuclear / Q000737:chemistry / Q000378:metabolism; D011817:Rabbits
D001360:Avidin; D015847:Interleukin-4; D001710:Biotin