AGENT FOR IMMUNOLOGICAL DIAGNOSIS AND A PROCESS FOR ITS PREPARATION

AGENT DE DIAGNOSTIC IMMUNOLOGIQUE ET PROCEDE DE PREPARATION

English Abstract

Abstract of the Disclosure

A process for preparing a carrier for use in the
detection and determination of a partner of an immunological
reaction, the associated partner being on the surface of the
carrier, in which the carrier is irradiated with gamma
radiation before or after the associated partner is bound
thereto. A polymeric carrier produced by the process is also
disclosed.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for preparing a polymeric carrier for use
in the detection and determination of an immunological
reaction partner present in a liquid contacted with the
carrier, the carrier having the associated partner bound
thereto, which process comprises irradiating the carrier
with gamma radiation before or after the associated partner
is bound to the carrier.

2. A process as claimed in claim 1 wherein the carrier
is irradiated with from 0.1 to 100 mégarads of gamma
radiation.

3. A process as claimed in claim 2 wherein the carrier
is irradiated with from 0.5 to 10 megarads of gamma
radiation.

4. A process as claimed in claim 1 wherein said
partner bound to the carrier is an antigen or antibody.

5. A process as claimed in claim 1 wherein said
polymeric carrier is of polystyrene or polyvinyl chloride.

Description

--2--
The invention relates to a carrier for the detection
and determination of an immunological reaction partner present
in a liquid, the associated partner being on the surface of the
c,^arrier.
It is known to bind a partner of an immunolo~ical
reaction adsorptively or covalently to a carrier in order
to isolate the corresponding partner from a solution in or-
der to detect this partner or to determine its amount.
However, it is al50 known that test methods based
On this principle can have deficiencies.
Thus, Chessum and Denmark describe, in The Lancet
(1978), page 161, that the known polystyrene microtiter
plates used as the carrier in a process for the deter-
mination of antigens or antibodies which is generally
called ELISA (Enzyme Linked Immuno Sorbent Assay) can
lead to intolerably large variations in the test result.
Bidwell et al. also report, in J. Infect. Disease 136,
Supplement, page 27~ (1977), variations in the results of
an ELISA test which it was possible to attribute to
differences in the microtiter plates used as the carrier.
These wide varia-tions in the test result which were caused
by differences in the surface properties of the microtiter plates
should not be restricted to the use of these plates, but should
also occur with carriers of a different shape made from the
same materials.
Accordingly, there was the object of discovering


'7'7~
--3--
carrier materials which have more uniform surface pro-
perties and which, when used, give immunological test
results which vary less.
Surprisingly, it has now been Eound that this
object can be achieved by irradiating the carrier
material, and preferably microtiter plates prepared
therefrom, with gamma rays, preferably with cobalt rays,
and preferably with 0.1 to 100, in particlular 0.5 to 10,
megarads.
The invention thus relates to a process for preparing
a polymeric carrier for the detection and determination o~ a
partner o an immunological reaction in which the corresponding
partner is on the surface of the carrier, wherein the
carrier is irradiated, before or after its surface has been
coated with this partner.
It is not necessary to coat the carrier immediately
after irradiation. The advantageous effect of irradiation
is also observed if a period of days or months
elapses between irradiation and coating.
In principle, all plastics, but in particular
polystyrene and polyvinyl chlcride~ can be used as
carrier materials in this process.
Irradiated carriers can advantageously be used in
immune test systems which are known per se, for example
immune test systems based on an antigen/antibody reaction,
for example ELISA systems (Enzyme Linked Immuno Sorbent Assay
systems), a bonding partner being bonded to the irradiated

77~
--4--
carrier.
Such bonding partners can be, for example, proteins,
such as immunoglobulins, antimicrobial anti-
bodies, plasma proteins, for example Clq, or antigenic
materials, for example allergens or microbial antigens.
The example whi.ch follows illustrates the invention:
EXAMPLE
Preparation of a test kit for the determination of anti-
bodies of the IgG class and IgM class against mumps
virus in human serum.
1. Bonding of the virus antigen to the carrier
(polystyrene microtiter plate)
a. irradiated (about 2 mrad~
b. not irradiated
15 2. Washing
3. Application and incubation of serum dilutions
4. Washing
5. Application and incubation of anti-human IgG- or
IgM-alkaline phosphatase conjugate
20 6. Washing
7. Application of the substrate solution
8. Stopping of enzymatic splitting by addition of
2N NaOH
9. Photometric measurement at 405 nm

~7~



Table
Comparison of the sensitivity of a test with an irradi-
ated carrier with that of a test with a non-irradiated
carrier:

Detection limit (titer 1:)
irradiated carrier non-irradiated carrier

Serum
IgG IgM ~ IgG I~M
A 20,480 20,480 1,280 2,560
10 3 1,280 160 640



The figures show the advantage of using irradi-
ated carriers. The detectability (sensitivity) is
significantly increased.