An immunoassay for histamine based on monoclonal antibodies.
Monoclonal antibodies with high specificity for histamine as well as for 1-methylhistamine were obtained after immunization of mice with a conjugate where the histamine was coupled via its ring 1-nitrogen to dog serum albumin. An immunoassay was developed for the quantitation of histamine release from basophils and 1-methylhistamine release from mast cells after provocation. The test method is based on competitive inhibition between histamine and a labelled histamine conjugate for the antigen binding sites of the antibodies. The separation step is performed by the addition of solid phase bound anti-mouse subclass specific antibodies. The sensitivity of the assay is 2 micrograms/l for histamine and 0.1 micrograms/l for 1-methylhistamine. No cross-reactivity was obtained with other metabolites of histamine or with histidine. Serotonin and dopamine were detectable, but only in doses (mg/l) well above the normal concentration found in the circulation. The immunoassay has been evaluated for its capacity to measure histamine release in vitro. A good correlation with the conventional fluorometric assay was obtained when histamine released from allergen stimulated leucocytes from allergic patients was tested. Urinary samples from patients undergoing hyposensitization showed a mean excretion of 1-methylhistamine at a level of 131 mumol MeHi/mol creatinine. The release of histamine and 1-methylhistamine in vivo was examined in plasma samples taken during a bronchial provocation test. A significant elevation above the basal analyte level occurred ten minutes after provocation.
Pharmacia Diagnosties AB, Uppsala, Sweden.
E
E
Hammar
A
A
Berglund
A
A
Hedin
A
A
Norrman
K
K
Rustas
U
U
Ytterström
E
E
Akerblom
D000818:Animals; D000911:Antibodies, Monoclonal; D006632:Histamine / Q000032:analysis*; D006636:Histamine Release; D006801:Humans; D007118:Immunoassay; D008761:Methylhistamines / Q000032:analysis; D051379:Mice; D008807:Mice, Inbred BALB C
D000911:Antibodies, Monoclonal; D008761:Methylhistamines; D006632:Histamine