JPS6165142A - Method for measuring immune reaction by using fluctuation of light intensity - Google Patents

Abstract

PURPOSE:To improve S/N and measurement accuracy by converting pho toelectrically the scattered light from a cell, taking out the output synchronized with the chopped light out of the outputs thereof and determining the power spectral density of the intensity fluctuation. CONSTITUTION:Antigen-antibody reaction arises in a cell 7 and the light scat tered by the pulverous particles formed by such reaction is made incident through a collimator 10 having a pair of pincholes to a photodetector 11 consisting of a photoelectron multiplier. The output monitor light of a photode tector 8 is supplied to a data processing unit 14 through a lock-in amplifier 103 which takes out only the light passed actually through a reference cell 102 in synchronization with the chopping operation of a chopper 101. The output signal from the photodetector 11 is supplied to the unit 14 through a lock-in amplifier 104 which takes out only the light passed actually through the cell 7 in sychronization with the chopping operation of the chopper 101. The result of the antigen-antibody reaction is outputted by the unit 14.

Description

DETAILED DESCRIPTION OF THE INVENTION (Prior Art) The present invention relates to an immune reaction measuring device that measures an antigen-antibody reaction by using intensity fluctuations of light scattered by fine particles.

There are immunoassay methods that utilize specific selective reactions of immune reactions as a method for measuring trace components in living bodies such as immune substances, hormones, medicines, and immunomodulators.They can be roughly divided into labeled immunoassays that use enzymes or radioactive isotopes as labeling substances. Two well-known methods are analytical methods and non-labeled immunoassay methods that directly measure antigen-antibody complexes.

The former labeled immunoassay is radioimmunoassay (
RIA), WI elementary immunoassay (E[A>, flea immunoassay Ui
(F I A) '8 Ka, j: <X+"I'
Although it has a sensitivity of 3, there are various limitations such as isotope absorption and rapid burying of waste, and the test cost is high because it takes a long time to measure and the labeling reagent is expensive. There are drawbacks such as.

The latter non-labeled immunoassay methods include immunoelectrophoresis, immunodiffusion, and precipitation, and although they are simple analytical methods, they are insufficient for precise measurements in terms of sensitivity, quantitative performance, and reproducibility. Regarding this type of immunoassay method, please refer to ``Clinical Test Methods Summary'' (edited by Izumihara Kanai and Masamitsu Kanai, Aftershock Publishing) and ``Clinical Test J
vo i, 22° No. 5 (1978), No. 471
It is explained in detail on pages 487 to 487.

Also, “l mmunochemistry, V
o i, 12°No, 4 <197'5), 34th
On pages 9 to 351, the average diffusion constant, which is an index of Brownian motion, which decreases compared to the size of aggregated particles, is calculated by reacting particles with i scales or antigens on their surfaces with antigens or antibodies. discloses a method for quantitatively analyzing antigens or antibodies by determining from changes in the spectral width of scattered laser light. This analysis method has the advantage of not using labeled reagents, but it uses a spectrometer to detect the broadening of the spectrum of incident light due to the Doppler effect caused by the Brownian motion of particles, so the disadvantage is that the equipment is large and expensive. In addition, errors occur when the spectrometer is mechanically driven, resulting in poor accuracy and reproducibility. Furthermore, this method only calculates the average diffusion constant from the spectral width of light, and has the disadvantage that the amount of information is small.

As mentioned above, conventional immunoassay methods use expensive labeling reagents, resulting in high analysis running costs, troublesome liquid handling and processing, long processing times, and high costs. The disadvantages are that it requires a large spectrometer, has poor accuracy and reproducibility, and provides only a small amount of information.

(Objective of the Invention) The object of the present invention is to utilize the fact that the intensity fluctuation of light scattered by fine particles is closely related to the antigen-antibody reaction.
By measuring antibody reactions, the above-mentioned drawbacks of the conventional methods are eliminated, and measurements can be performed with high accuracy and reproducibility without using simple bleaching reagents or expensive and large spectrometers. Furthermore, it is possible to shorten the measurement time and automate the antigen-antibody reaction measurement, and to improve the SZN ratio by removing not only background noise but also the noise of the sample itself. The present invention aims to provide an immune reaction measuring device that can obtain a lot of useful information about reactions.

(Summary of the Invention) The immune reaction measurement device of the present invention projects light onto a reaction solution containing an antigen and an antibody, and immobilizes the antibody or antigen added to the scattered light or reaction wave by fine particles generated by the antigen-antibody reaction. In this apparatus, the antigen-antibody reaction is measured based on the power spectrum density of the intensity fluctuation of the detected output by detecting scattered light generated by the antigen-antibody.
A cell that contains a reaction solution for performing an antibody reaction, a light source device that emits coherent chopped light and makes it enter the cell, and a photodetector that receives scattered light from the cell together with the used or used light. Then, a lock-in amplifier extracts the output signal from the photodetector in synchronization with the chopped light, receives the output signal from this lock-in amplifier, calculates the power spectrum density of the intensity fluctuation, and calculates the power spectrum density of the intensity fluctuation. The method is characterized by comprising a means for measuring an antigen-antibody reaction.

In the above-mentioned immune reaction measuring device of the present invention, antigen-
The intensity of scattered light generated by fine particles generated as a result of antibody reaction or the scattered light generated by antigen-antibody reaction of fine particles on which antibodies or antigens are immobilized fluctuates due to light interference, so the power spectrum of this intensity fluctuation is Focusing on the fact that density depends on the shape and size of particles, we can detect the antigen-antibody reaction by detecting the power spectrum density of intensity fluctuations. A lot of useful information can be obtained, such as the presence or absence of δ, the quantification of antigen or antibody, and the state of aggregation (particle size distribution) of fine particles due to antigen-antibody reactions. In this way, in the present invention, scattered light is received by a photodetector and fluctuations in the output signal intensity are detected, so there is no need to use a labeling reagent, and since spectral analysis of scattered light is not performed, spectroscopic There is no need to use a meter. Furthermore, since the irradiated light is chopped by the chopper in order to reduce the scattered light by 1q, the S/N ratio in the output signal due to the scattered light can be improved.

In one embodiment of the present invention, which will be described later, scattered light is detected in a homodyne manner, and the relaxation frequency of the power spectrum density of the intensity fluctuation depends on the particle size.
Find the ratio of relaxation frequencies before and after the antigen-antibody reaction,
The antigen-antibody reaction is measured from this ratio value. In other embodiments, the integral value before and after the antigen-antibody reaction can be calculated by taking advantage of the fact that the integral value of the power spectrum density of the power spectral density of the intensity fluctuation of scattered light depends on the size of the particles. The antigen-antibody reaction is measured from the value of this ratio.

In the present invention, changes in the intensity fluctuation of light scattered by particles due to agglomeration of particles are detected based on the power spectrum density.
It is possible to obtain a large amount of useful data regarding antigen-antibody reactions in a short time with high sensitivity and high reproducibility without using specific labeling reagents or spectrometers.

(Example) FIG. 1 is a diagram showing the configuration of an example of the immune reaction measuring device according to the present invention. In this example, a He--Ne gas laser 1 with a wavelength of 632.8 qm is provided as a light source that emits coherent light. In addition to such a gas laser, a solid laser such as a semiconductor laser can also be used as a light source that emits coherent light. light 11iii1
A chopper 101 performs a chopping operation to turn on and off the laser beam 2 emitted from the laser beam 2 at a certain frequency. The chopped light after the chopping operation is separated into a light beam 4 and a light beam 5 by a semi-transparent mirror 3. The chopping frequency at this time needs to be a frequency that does not overlap with the frequency component of the intensity fluctuation, for example, a frequency of 1 kHz or more. One of the light beams 4 is condensed by a condensing lens 6 and projected onto a transparent self.

The other light beam 5 is made incident on a photodetector 8 made of a silicon photodiode via a reference cell 102 containing a standard sample, for example, a buffer containing fine particles, and the output light intensity of light #i1 and the difference between the FRs of the standard sample are determined. It is converted into a monitor signal that represents fluctuations due to drift.

The self contains an antigen-antibody reaction solution, which is a mixture of a buffer solution in which fine particles 9 having antibodies or antigens bound to their surfaces are dispersed, and a test solution containing the antigen or antibody. Therefore, an antigen-antibody reaction occurs in the self, and interactions occur between microparticles, and microparticles adhere to each other.
The state of Brownian motion will change. Scattered light scattered by the fine particles 9 in the self is made to enter a photodetector 11 consisting of a photomultiplier tube through a collimator 10 having a pair of pinholes. The output monitor signal of the photodetector 8 is supplied to the data processing device 14 via a lock-in amplifier 103 that extracts only the light that actually passed through the reference cell 102 in synchronization with the chopping operation of the chopper 101 .

Further, the output signal of the photodetector 11 is also supplied to the data processing device 14 through a lock-in amplifier 104 that extracts only the light that actually passed through the self in synchronization with the chopping operation of the chopper 101. data (l!l management device 14 has A/
D conversion unit 17. A fast Fourier transform section 18 and an arithmetic processing section 19 are provided to perform signal processing as described later and output measurement results of antigen-antibody reactions. This measurement result is supplied to the display device 20 and displayed.

The scattered light intensity from the self is normalized by the short-time average value output of the antigen intensity monitor signal from the photodetector 8, and after removing the fluctuation of the laser light intensity emitted from the light source and the drift of the standard sample over time. The power spectrum density of the intensity fluctuation of the scattered light is determined, and based on this, the state of aggregation of the fine particles 9 in the self, and therefore the progress state of the antigen-antibody reaction, is measured.

FIG. 2 is a diagram showing a detailed configuration of the collimator 10 shown in FIG. 1. The collimator 10 of this example has a cavity structure, and the cavity 10a has a dark box structure to remove the influence of external light, and its inner surface has an antireflection structure.

';:1iQilt of 1li10a forms pinholes +ob and +Oc. Now, the radius of these bin holes 10b83 and 10c are a+B and a2, respectively.
．． The distance between the pinholes is calculated, and the refractive index of the inner part of the cavity 10a' is set to 11. When the wavelength is λ, the configuration is made to satisfy the following equation (1).

In the present invention, as described above, the power spectral density of the intensity fluctuation of the scattered light is detected, but this power spectral density includes a component due to the fluctuation of the interference component caused by the scattering of the fine particles over a distance of about the wavelength. The fluctuation of the scattered light due to interference is observed as a spatial fluctuation of the speckle pattern, but this is directly reflected in the wide light receiving field. When the light is incident on the photodetector 11 having a surface, spatial smoothing is performed over the area of the light receiving surface, so the detected fluctuation becomes small. Therefore, by limiting the field of view of the photodetector 11 using the collimator 10 having a pinhole as described above, fluctuations can be detected with high sensitivity.

In this example, in order to add (^) to the above formula (1), the cavity 10
The medium in a is air with a refractive index of 11=1, which is sufficiently practical. That is, a pinhole 10b with a diameter of 0.3 mm,
If a collimator 10 with 10c separated by 30 cm is used, the above formula (1) will be satisfied.

In the above embodiment, the direction of the light beam 4 incident on the self and the optical axis direction of the collimator 10 are set at 90 degrees, and the homodyne method is adopted in which the incident light beam does not directly enter the photodetector 11. It is also possible to adopt a heterodyne method in which a portion of the light is incident on the photodetector 11. That is, in the present invention, as shown in FIG. 3, the angle θ between the light beam 4 incident on the self and the optical axis of the collimator 10 can be set arbitrarily. When detecting the scattered light in a homodyne manner, the output signal of the photodetector 11 consisting of a photomultiplier tube is proportional to the average value ES2 of the square of the electric field strength of the scattered light ES. In the case of heterodyne detection in which scattered light and incident light are detected together, if the electric field strength of directly incident light is Ee, the output signal of the photodetector 11 becomes .E + ES2. Here, since E has no fluctuation (it is made gentler than the fluctuation of the scattered light even if there is a dust), the fluctuation component of the output of the photodetector 11 is almost entirely the second term 2Ee −
Equal to ES. In other words, an output signal approximately proportional to the electric field strength E of the scattered light can be obtained.

Further, the collimator 0 is not limited to the above-mentioned configuration, but may have any configuration as long as it can limit the field of view of the photodetector 11 to one speckle pattern or less.

Using the above-described device, the output signal of the photodetector 11 is supplied to the data processing device 14 via the lock-in amplifier 104,
Along with the monitor signal from photodetector 8! , :2!1 The result of determining the power spectrum density of the intensity fluctuation of the scattered light will be explained next. Here, the power spectral density S(') of steady established overculm x (t) can be expressed as follows.

Based on equation 2), the power spectral density is estimated using a fast Fourie transform. The output signal from the photodetector 11 is output by the lock-in amplifier 104.
Data ffi I! ! The quantization level of the A/D conversion in the device 14 was amplified so that the direct signal coverage was as wide as possible, and the quantized data was processed by a microprocessor to obtain the power spectral density. The progress status of the immune reaction was numerically displayed on the display device 20 from the power spectral density obtained in this manner.

In Figures 4 and 5, the particle size is 0.1g, respectively! 1
This shows the power spectrum density obtained when a liquid containing latex particles of μn+, P3, and 0.305 μn1 is placed in a self-contained cell. Some of the power spectral density of the fluctuation is due to interference effects. It can be seen that the relaxation frequency of these power spectral densities is inversely proportional to the particle diameter. In other words, the intensity fluctuation of the scattered light is a combination of the component due to the interference of coherent light exposed to the movement of fine particles as described above, and the component due to fluctuations in the number of particles within the scattering volume. In this case, interference components are mainly detected.
The relaxation frequency of the power spectrum signature is the reciprocal of the time it takes for a particle to travel the distance of the wavelength of light, so as the particle size increases, the travel time becomes longer and the relaxation frequency decreases.

In FIG. 6, the horizontal axis represents the grain size in micrometers, and the vertical axis represents the relaxation frequency, each plotted on a logarithmic scale.

In other words, the relaxation frequency for particles with a particle size of 0.0915 μm is approximately 400)1z, and for particles with a particle size of 0.188 μm, it is approximately 200H.
When z is 0.305 μm, it is approximately 100 H2.

As is clear from the graph of FIG. 6, the relaxation frequency of the power spectral density is inversely proportional to the particle size, so the presence or absence of antigen-antibody aggregation and the degree of aggregation can be detected from changes in this relaxation frequency.

Figures 7 and 8 are graphs showing the power spectrum density when latex particles with a particle size of 0.3 μm are dispersed in a buffer solution at concentrations of 0.1% by weight and 0.09% by weight. , it can be seen that Lorentzian power spectral densities are obtained in both cases. As mentioned above, the intensity fluctuation of scattered light is the sum of the coherent component due to the Brownian motion of particles and the incoherent component due to changes in the number of particles within the scattering volume, but as the number of particles within the scattering volume decreases. When the amount of interfering components decreases to the same level as non-interfering components, components other than changes in scattered light intensity due to Brownian motion of particles will also be detected, making it difficult to accurately detect antigen-antibody reactions. It disappears. Therefore, the concentration of particles needs to be selected in a range that is low enough to obtain a sufficient intensity of incident light within the scattering volume and such that the coherent component is larger than the incoherent component.

However, if the particle size of the scatterer is constant, the relative fluctuation will be constant over a fairly wide range of particle temperatures.

Figures 10 and 11 show that immunoglobulin G antibodies immobilized on the surface of latex particles with a diameter of 0.3 μm were dispersed in a buffer solution adjusted to pH 7 with TriS-HCI, and 10% of the antigen was used as an antigen. An antigen-antibody reaction solution containing immunoglow 1 phosphorus at a concentration of -0/'m (2 and 10-'q/mλ) was placed in a cell, and the cells were incubated for 15 minutes before and after the start of the antigen-antibody reaction. Figure 10 shows the power spectral density of the antigen concentration 10-'g/
In the case of the m offender, the relaxation frequency before the reaction is approximately 5011 z, while the relaxation frequency within 15 minutes of the reaction is 10 Hz.
is changing. This was burnt until the antigen concentration was 10'g.
/m fl, the relaxation frequency before the reaction starts is about 9
587. The relaxation frequency after the reaction is approximately 40 Hz. Therefore, the ratio F of the relaxation frequencies before and after the antigen-antibody reaction is defined as the relaxation frequency after the antigen-antibody reaction, and this (direction) is calculated for the anti-1 quintillion relaxation rate as shown in Figure 12. In other words, in Figure 12, the horizontal axis i is the antigen concentration and the vertical axis is the value of the relaxation frequency ratio F, but it is necessary to find the relaxation frequency ratio F. The antigen yA degree can be detected by this method.

On the other hand, in FIG. 10 J3 and FIG. 11, it can be seen that the ratio (R) of relative fluctuation before and after the antigen-antibody reaction has a certain relationship with the antigen concentration. At this time, the relative fluctuation can be calculated by finding the relaxation frequency fr from the graph of the power spectral density. At this time, the relative fluctuation ratio R can be expressed by the following equation.

The relative fluctuation ratio R was determined using this equation (3), and its relationship with the antigen concentration was determined in a graph as shown in FIG. 13. As is clear from this graph, the unknown antigen moisture content can be determined by determining the ratio R of relative fluctuation before and after the antigen-antibody reaction. That is, prior to measurement, the relative fluctuation ratio R is determined for the sample t1!1 samples with different known antigen concentrations, and a calibration curve is obtained as shown in Figure 13. ratio R
The antigen concentration can be determined based on the previously determined calibration curve.

On the other hand, the relative fluctuation ratio R according to equation (3) can also be determined as a ratio of changes in the integral value in the low frequency band of the power spectral density shown in FIGS. 10 and 11. In other words, the relative fluctuation ratio R can be determined based on the following.

When the particle size is constant, the power spectral density is Lorentzian and decreases inversely as the square of the frequency at frequencies greater than the relaxation frequency.

However, when the particle sizes are distributed, a superposition of Lorentzian spectra with relaxation frequencies corresponding to each particle size is observed, so the power spectral density in the high frequency part is no longer the square of the frequency. is no longer inversely proportional to . Therefore, from the shape of this part, the particle size distribution of the particles aggregated by the reaction can be determined.

This kind of data has not been available in the past,
This is useful information in analyzing the state of anti-Ikyo-antibody reaction.

FIG. 14 is a diagram showing the construction of another embodiment of the immune reaction measuring device according to the present invention. J51 in the embodiment shown in FIG.
a''C, the same parts as in Fig. 1 are given the same reference numerals and their explanations are omitted.In this example, in order to obtain the chopped beam of luminous flux 2, a chopper is not used, but the laser beam is generated by the modulator +05. +11ii1 is directly modulated to obtain chopped light.

FIG. 15 is a diagram showing the structure of still another example of the immune reaction measuring device according to the present invention. d3 in the embodiment shown in FIG.
In C, the same parts as in FIG. 1 are designated by the same number 71, and the explanation thereof will be omitted. In this example, after the light beam 2 emitted from the laser light source 1 is divided into two light beams 4 and 5 by the semi-transparent mirror 3, choppers 106 and 107 are provided separately for the light beams 4 and 5 to separate the light beams 4 and 5, respectively. Chogging operation is being performed on 5. At this time, the chopped lights are obtained so that the phase of each chopped light is inverted, that is, when one is QN, the other is OFF as shown in Fig. 16 (a>, (b). The monitor signal corresponding to various drifts detected by the photodetector 8 via the cell 102 and the scattered light intensity signal including the influence of each scale drift detected by the photodetector 11 via the roll 7 are the 17th Figures (a), (b)
The result will be as shown in . The oblique 1 part in the figure shows the fluctuation of the laser light intensity emitted from the light source and the drift of the standard sample with respect to time;
The monitor signal shown in <b) and the scattered light intensity signal are added to the adder 10.
If Korea is entered at 8, the result will be as shown in Figure 17 (C). Therefore, if this signal is passed to lock-in amplifier +09,
It is possible to obtain 1q of scattered light intensity signals from which various drift I~ components have been removed.

The invention is limited only to the embodiments described above.
It is possible to make many modifications and changes. Although the above explanation was given as an example for immunoglobulin G ([]G),
Immunoglobulin Δ (IgA).

It can be applied to the measurement of all substances that cause agglutination due to antigen-antibody reactions, such as rc+ M, IQ D, Ifl E, Australian antigen, syphilis antigen, and insulin. In addition, in the above-mentioned example, antibodies were immobilized on the surface of microparticles to detect antigens in the specimen, or antigens were immobilized on the surface of microparticles to detect antibodies in the specimen. It can also be detected. Furthermore, although polystyrene latex particles were used as the fine particles in the above embodiments, other organic particles or inorganic particles such as glass may also be used.

In the example briefly described above, fine particles were present in the antigen-antibody reaction solution from the beginning. You can also use it. An example of such an antigen-antibody reaction is a reaction in which human chorionic gonadotropin (HCG) is used as an antigen and anti-human chorionic gonado 1 to 1 to 100% (anti-HCG) is used as an antibody. After antigen-antibody combination is minute 4:☆
You can treat it like a child. Furthermore, the antigen itself can also be used as particles. In such an antigen-antibody reaction, Candida albicans (yeast) is used as an antigen.
It is also possible to use anti-Candig albicans as an antibody, or to have blood cells, cells, microorganisms, etc. as particles in the pond. The first embodiment shown in Figure 1 was a batch method in which the antigen-antibody reaction solution was stored in a cell and measured, but a flow-type method was used in which the measurement was performed while the antigen-antibody reaction solution was continuously flowing. Of course, it is also possible.

(Effect of the invention> The effects of the present invention described above are summarized as follows.

(1) Since there is no need to use reagents that are expensive and difficult to handle, such as labeling reagents such as enzymes and radioisotopes, it can be carried out in a simple and easy manner.

(2) It has higher precision and reproducibility than non-labeled immunoanalysis methods such as immunoelectrophoresis, immunodiffusion, and precipitation, so it is possible to obtain highly reliable measurement results with high precision.

(3) Since the method detects intensity fluctuations of scattered light based on the Brownian motion of fine particles, highly accurate measurement can be performed using an ultra-trace amount of sample, and the measurement time can be shortened.

(4) Determining the average diffusion constant from changes in the spectral width of scattered light does not require a spectrometer compared to methods that quantify antigens or antibodies, so the device is small and safe, and has high accuracy and reliability. High measurement results can be obtained.

(5) Since measurements are performed based on the power spectral density of optical fluctuations, a lot of useful information about antigen-antibody reactions can be obtained.

(6) A chopping operation is performed on the laser light source to use the chopped light as irradiation light for the sample, and only the signal synchronized with the chopped light is extracted by lock-in detection, so there is drift of the sample itself as well as background noise.
It is possible to effectively remove noise, improve the S/N ratio, and significantly improve measurement accuracy.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an embodiment of the immune reaction measuring device according to the present invention, FIG. 2 is a diagram showing the detailed configuration of the collimator, and FIG. Diagrams showing the structure of the main parts of other examples, FIGS. 4 and 5, have particle sizes of o and iaaμm, respectively.
6 Power spec 1 for fine particles of 0,305 μm
Figure 6 is a graph showing the relationship between particle size and relaxation frequency of power spectrum intensity. Figures 7 and 8 are graphs showing the particle density at 0.1% suspension, respectively.
and 0609% by weight. Figure 9 is a graph showing the relationship between particle concentration and relaxation frequency.
The figure shows antigens, -degree or 1O-4Q, -'mf21-, respectively.
r and 10-3 g/m, +2 vs # le anti-UN -
fA Graph showing the power spectral density before and after body anti-LQ+ J3-L G- Figure 12 is a graph showing the relationship between antigen concentration and relaxation frequency ratio, Figure 13 is a graph showing the relationship between antigen concentration and relative fluctuation ratio. FIG. 14 J3 and FIG. 15 are diagrams showing the configuration of other examples of the immune reaction measuring device according to the present invention, and FIGS. Waveform diagrams showing light. FIGS. 17(a) to (C) are waveform diagrams showing a monitor signal, a scattered light intensity signal, and a steering signal, respectively. 1... Laser light source 2. 4. 5... Luminous flux 3
...Semi-transparent mirror 6...Condensing lens 7...Roll 8...Photodetector 9...
Fine particles 10...Collimator 11...Photodetector 13.15...Low noise amplifier 14...
Data processing device 16...Low pass filter 2o...
・Display display 10a ・・Empty pull + Ob, 1
0c - Pinhole 101, 106, 107...
Jopper 102...Reference cells 103, 104, 109...Lock-in amplifier 10
5...Modulator. Patent applicant: Olympus Optical Industry Co., Ltd. Figure 2 Figure 3 (ZH) m! Small Figure 13 Mine Drama ((/ml)

Claims (1)

[Claims] 1. Light is projected onto a reaction solution containing an antigen and an antibody, and the antigen-
Detects the scattered light caused by fine particles generated by the antibody reaction or the scattered light generated by the fine particles immobilized with antibodies or antigens added to the reaction solution, and detects the antigen-antibody reaction based on the power spectrum density of the intensity fluctuation of this detection output. The measuring device includes a cell containing a reaction solution for performing the antigen-antibody reaction, a light source device that emits coherent chopped light and makes it incident on the cell, and a light source that emits coherent chopped light and makes it incident on the cell, and a light source that uses scattered light from the cell alone or as incident light. A lock-in amplifier that extracts the output signal from the photo-detector in synchronization with the chopped light, and a power spectral density of the intensity fluctuation that receives the output signal from the lock-in amplifier. 1. An immune reaction measuring device using light intensity fluctuation, characterized in that it comprises means for determining the antigen-antibody reaction based on the determined antigen-antibody reaction. 2. The light source device comprises a laser light source that generates coherent light, a chopper that generates chopped light from the coherent light, and a semi-transparent mirror that divides the chopped light into two. The immune reaction measuring device according to scope 1. 3. A patent characterized in that the light source device comprises a laser light source that generates coherent light, a modulator that modulates this laser light to obtain chopped light, and a semi-transparent mirror that divides this chopped light into two. The immune reaction measuring device according to claim 1. 4. One of the chopped lights split into two by the semi-transparent mirror is incident on the cell, and the other is incident on a drift correction device consisting of a reference cell, another photodetector, and another cock-in amplifier to generate a drift correction signal. 4. The immunological apparatus according to claim 2, wherein the drift correction signal is used to remove the influence of drift from the output signal from the lock-in amplifier.