Aus der Arbeitsgruppe Immunologie der Tierärztlichen Hochschule ...

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The seasonal kinetics in degree of sensitisation varied amongst the horses without any obvious
correlation to seasonal or climatic influences including the time of intense allergen exposition.
In agreement with results mentioned above also these adult horses displayed discordant
reactions – mainly in September - regarding negative reactions with the antiserum to bridge
membrane bound immunoglobulins on basophils but positive ones with the allergen
preparation from Culicoides nubeculosus. Again, this points towards at least two different
isotypes on the surface of basophils accounting for type I allergic reactions.
5. How did the functional in vitro test (FIT) for type I allergies prove good under field
conditions during the different seasons ?
A striking advantage of the FIT is the parallel detection of the total histamine content in the
cells (via physical and antibody mediated release), the “general” sensitisation with functional
membrane bound antibodies on basophils irrespective of their antigen specificity plus the
quantitative verification of specific sensitizing antibodies reacting with allergen preparations
in a dose dependent manner. Only with these synchronized information from one blood
sample important new facts as well as indications could be achieved (concerning the results in
questions 1 to 4of this summary).
A still remaining deficiency of the FIT is due to the fact, that the antiserum against equine
immunoglobulines used up to now, is obviously not detecting all cell-bound functional
antibodies responsible for a degranulation of basophils. The use of antibodies, capable of
detecting all equine immunoglobulins, including the functional isotypes on basophils, is
required.