Name: fluorescent antibody staining in cells
Uploaded: 2023-04-30T11:59:57.000Z
Duration: 1 min 12 s
Channel: JoVE

면역형광 현미경 검사에서 형광단이 표지된 항체는 특정 표적 또는 항원에 결합할 때 형광을 방출합니다.
면역형광 현미경 검사는 빛을 사용하여 형광단의 전자를 더 높은 에너지 상태로 여기시킵니다. 바닥 상태로 돌아갈 때 전자는 더 긴 파장의 빛을 방출합니다.
이러한 방출 또는 형광을 통해 조직 내의 특정 세포 또는 세포 내의 특정 단백질을 시각화할 수 있습니다.
면역형광은 1차 형광단 표지 항체가 표적 단백질에 결합할 때 직접적으로 발생할 수 있습니다. 또는 형광단으로 태그된 2차 항체가 관심 단백질에 부착된 특정 1차 항체와 결합하는 간접적일 수 있습니다. 그 결과 발생하는 형광은 직접 면역형광에서 방출되는 형광보다 강합니다.
직접 면역형광은 조직 내 비정상적인 단백질 응집을 감지하는 데 사용되며, 간접 면역형광은 자가면역질환 진단 시 혈청 내 순환 항체를 검출할 수 있습니다.

<ol>
	<li>Odell, I.D. 및 Cook, D., 2013. 면역형광 기술. The Journal of investigative dermatology, 133(1), p.e4.</li>
	<li>Sanderson, M.J., Smith, I., Parker, I. 및 Bootman, M.D., 2014. 형광 현미경 검사. 콜드 스프링 하버 프로토콜, 2014(10), pp.pdb-top071795.</li>
</ol>

면역형광현미경

Immunofluorescence Microscopy

형광현미경은 형광색소라고 불리는 형광 발색단을 사용하는데, 이는 광원으로부터 에너지를 흡수한 다음 이 에너지를 가시광선으로 방출할 수 있습니다. 형광색소에는 천연 형광 물질(예: 엽록소)과 대비를 만들기 위해 표본에 추가되는 형광 얼룩이 포함됩니다. 텍사스 레드 및 FITC와 같은 염료가 형광색소의 예입니다. 다른 예로는 핵산 염료인 4',6'-diamidino-2-phenylindole(DAPI) 및 아크리딘 오렌지가 있습니다.

현미경은 자외선이나 청색광과 같은 단파장 여기로 샘플을 조사합니다. 발색단은 여기광을 흡수하고 더 긴 파장의 가시광선을 방출합니다. 그런 다음 여기광을 필터링하여(부분적으로 자외선은 눈에 해롭기 때문에) 가시광선만 접안 렌즈를 통과하여 어두운 배경에 밝은 색상의 표본 이미지를 생성합니다.

형광 현미경은 병원체를 식별하고, 환경 내 특정 종을 찾거나, 세포 내 특정 분자 및 구조의 위치를 찾을 수 있습니다. 특정 형광색소를 흡수하는지 여부에 따라 살아있는 세포와 죽은 세포를 구별하는 접근법도 개발되었습니다. 때로는 서로 다른 구조나 특징을 보여주기 위해 동일한 표본에 여러 형광색소가 사용되기도 합니다.

형광현미경의 가장 중요한 용도 중 하나는 면역형광법으로, 이는 항체가 미생물에 결합하는지 여부를 관찰하여 특정 미생물을 식별하는 데 사용됩니다. (항체는 특정 병원체에 부착하여 이를 죽이거나 억제하는 면역 체계가 생성하는 단백질 분자입니다.) 이 기술에는 직접 면역형광 분석법(DFA)과 간접 면역형광 분석법(IFA)의 두 가지 접근 방식이 있습니다. DFA에서는 특정 항체(예: 광견병 바이러스를 표적으로 하는 항체)가 형광색소로 염색됩니다. 검체에 표적 병원체가 포함되어 있으면 형광 현미경으로 병원체에 결합하는 항체를 관찰할 수 있습니다. 염색된 항체가 병원체에 직접 부착되기 때문에 이는 1차 항체 염색입니다.

IFA에서는 2차 항체가 1차 항체가 아닌 형광색소로 염색됩니다. 2차 항체는 유기체에 직접 부착되지 않고 1차 항체에 결합합니다. 염색되지 않은 1차 항체가 병원체에 결합하면 형광성 2차 항체가 1차 항체에 결합하는 것을 관찰할 수 있습니다. 따라서 2차 항체는 병원체에 간접적으로 부착됩니다. 여러 개의 2차 항체가 1차 항체에 부착되는 경우가 많기 때문에 IFA는 검체에 부착된 형광 항체의 수를 늘려 특징을 더 쉽게 시각화할 수 있습니다.

본 텍스트는 Openstax, Microbiology 2e, Section 2.4: Staining Microscopic Specimens에서 발췌한 것입니다

형광 현미경은 형광 색소라고 하는 형광 발색단을 사용하는데, 이 발색단은 광원에서 에너지를 흡수한 다음 이 에너지를 ...

Education

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JoVE Core

Cell Biology

세포생물학

Unit 1

제1단원

Visualizing Cells, Tissues, and Molecules

세포, 조직 및 분자의 시각화

KEY TERMS AND CONCEPTS

주요 용어 및 개념

fluorescent antibody staining in cells

Fluorescent antibody staining uses a fluorescence microscope to make cells and microbes visible in bright colors against a dark background. The microscope works with fluorochromes, which are fluorescent dyes that absorb energy from a light source and then give off visible light. Some fluorochromes are natural, such as chlorophylls. Others are added to the specimen to improve contrast.

Common examples of fluorochromes include Texas red and FITC. The method can also use nucleic acid dyes such as DAPI, which stands for 4',6'-diamidino-2-phenylindole, and acridine orange. The sample is exposed to short-wavelength light, such as ultraviolet or blue light. The fluorochromes absorb this excitation light and emit light at a longer wavelength.

The microscope then filters out the excitation light. This is done partly because ultraviolet light can harm the eyes. Only the visible light reaches the ocular lens. That is why the specimen appears in bright colors on a dark background. Fluorescence microscopy can help identify pathogens, locate particular species in an environment, and show where molecules or structures are found inside a cell.

Some fluorescence methods can also help tell living cells from dead cells. They do this by using fluorochromes that are taken up differently by the cells. In some specimens, more than one fluorochrome is used at the same time. This lets scientists show different structures or features in the same sample.

A major application of this technique is immunofluorescence. Immunofluorescence identifies certain microbes by checking whether antibodies bind to them. Antibodies are protein molecules made by the immune system that attach to specific pathogens and help kill or block them. The method has two forms: direct immunofluorescence assay, or DFA, and indirect immunofluorescence assay, or IFA.

In DFA, the specific antibodies are stained with a fluorochrome before they are added to the specimen. For example, antibodies that target the rabies virus can be used this way. If the pathogen is present, the stained antibodies bind directly to it under the fluorescent microscope. This is called a primary antibody stain because the stained antibodies attach straight to the pathogen.

In IFA, the primary antibodies are not stained. Instead, the secondary antibodies carry the fluorochrome and bind to the primary antibodies. After the unstained primary antibodies attach to the pathogen, the fluorescent secondary antibodies can be seen attached to them. This makes the pathogen appear indirectly labeled. Because several secondary antibodies can bind to one primary antibody, IFA often produces a stronger fluorescent signal and makes the specimen easier to see.

Fluorescent Antibody Staining in Cells

imaging biological samples with optical microscopy

imaging-biological-samples-with-optical-microscopy

How Light Microscopes Bring Samples Into View

Optical microscopy uses light and lenses to make tiny biological samples visible. Antonie van Leeuwenhoek built the first compound optical microscope in the 17th century to view blood cells, bacteria, and yeast cells. In 1830, Joseph Jackson Lister developed an essentially modern light microscope. During the 20th century, microscopes gained better magnification and resolution. A sample is placed on a glass slide and clipped onto the stage, which is the flat platform of the microscope. The...

phase contrast and differential interference contrast microscopy

phase-contrast-and-differential-interference-contrast-microscopy

Microscope Contrast for Live, Unstained Cells

Phase-contrast and differential interference contrast microscopy help scientists see live cells without stains. Both methods boost contrast so thin, transparent structures become easier to study under the microscope. Phase-contrast microscopes use interference between light that passes straight through a cell and light that is refracted by cell parts. The microscope uses an annular stop in the condenser to make a hollow cone of light. The objective lens also contains a phase plate with a phase...

fixation and sectioning

Microscope Slide Prep and Staining

Microscope slide preparation includes wet mounts, fixation, and staining. These steps help make specimens easier to see under a light microscope. They also help preserve cells and highlight important structures. A wet mount is the simplest slide preparation. The specimen is placed in a drop of liquid on the slide. A liquid sample can be added directly with a dropper, and a solid sample, such as a skin scraping, can be placed on the slide before the liquid is added. The liquid is sometimes...

immunofluorescence microscopy

Fluorescent antibody staining uses a fluorescence microscope to make cells and microbes visible in bright colors against a dark background. The microscope works with fluorochromes, which are fluorescent dyes that absorb energy from a light source and then give off visible light. Some fluorochromes are natural, such as chlorophylls. Others are added to the specimen to improve contrast. Common examples of fluorochromes include Texas red and FITC. The method can also use nucleic acid dyes such as...

immunocytochemistry and immunohistochemistry

immunocytochemistry-and-immunohistochemistry

Antibody Staining in Cells and Tissues

Immunocytochemistry (ICC) and immunohistochemistry (IHC) use antibodies to detect specific proteins or antigens in samples. ICC focuses on individual cells, such as blood cells and stem cells. IHC is used for tissue samples. These methods were first published by Albert Coons in 1941, when they were used to detect pneumococcal antigen in mouse tissue sections from mice infected with Pneumococcus. Both techniques can produce either a colored signal or a fluorescent signal. Enzyme-conjugated...

confocal fluorescence microscopy

Confocal Microscopy for Sharp Cell Images

Confocal microscopy is an advanced imaging method used to capture sharp fluorescence images. Its main advantage is that it blocks out-of-focus light from the sample with pinholes. That helps produce high-resolution images with strong contrast. Unlike a standard optical microscope, a confocal microscope uses a focused laser beam to scan the sample surface at different z-planes. This makes it especially useful for thick specimens, such as biofilms. These samples can often be examined alive and...

protein dynamics in living cells

Fluorescent Methods for Protein Movement

Protein movement in living cells can be measured with fluorescence-based methods such as FRAP, FRET, and PET. These techniques help scientists track how proteins move, interact, and change distance inside the cell. Fluorescent recovery after photobleaching, or FRAP, measures protein movement rates within the cell. In this method, a small region is exposed to a strong laser beam. The beam permanently bleaches fluorophore-tagged proteins in that area. Over time, bleached proteins diffuse away...

total internal reflection fluorescence microscopy

total-internal-reflection-fluorescence-microscopy

Surface-Only Imaging with TIRF Microscopy

Total internal reflection fluorescence microscopy, or TIRF, is a microscope method used to view fluorophores near a solid surface with a higher refractive index, such as a glass coverslip. It is useful when scientists want to study signals close to the cell surface. TIRF works when light from a medium with a lower refractive index, such as air, hits the glass coverslip at a critical angle. Instead of entering the glass, the light undergoes total internal reflection. This reflection creates an...

atomic force microscopy

Atomic Force Microscopy for Surface Mapping

Atomic force microscopy is used to map the surface details of materials. It can examine ceramics, glass, polymers, and biological samples. The method gives far more resolution than an optical imaging system and produces three-dimensional surface profiles instead of flat 2D images. The probe is the key part of an AFM setup. It includes the cantilever and tip assembly, and it is also the part that is replaced most often. Constant contact with samples wears down the tip, so probe choice depends...

super-resolution fluorescence microscopy

Sharper Cell Images with Fluorescence Microscopy

Super-resolution fluorescence microscopy gives sharper images than standard fluorescence microscopy by reducing the point spread function, or PSF. The PSF is the light pattern from a point source that makes it look blurred. Because of this blur, each fluorescent spot appears larger than it really is. Nearby fluorophores can also overlap through their PSFs and make the image less clear. Several super-resolution methods have been developed to improve image detail. Photoactivated localization...

overview of electron microscopy

Electron Microscopy: TEM vs SEM

Electron microscopy uses electrons instead of visible light to make images with much higher detail than a light microscope. Visible light limits the resolution of light microscopes, which usually magnify up to 1000X, and sometimes up to 1500X. Electrons have a much shorter wavelength, about 0.005 nm, so they can produce resolution as fine as 0.05 nm. An electron microscope can also magnify images up to 2,000,000X and reveal subcellular structures and some molecular structures, including single...

scanning electron microscopy

How SEM Reveals Surface Details

A scanning electron microscope (SEM) reveals the surface details of a sample with an electron beam. The beam scans across the sample in a two-dimensional pattern. SEM can image areas from about 1 centimeter down to 5 micrometers wide. SEM is useful for studying bacteria, viruses, tissues, and larger samples such as insects. Conventional SEM can produce magnification from 20X to 30,000X. It also offers spatial resolution of about 50 to 100 nanometers. The process starts when the electron gun...

transmission electron microscopy

How TEM Reveals Tiny Structures

Transmission electron microscopy uses electrons to reveal very small structures inside a specimen. The technique grew from the first electron microscope prototype developed in 1931 by physicist Ernst Ruska. He built on the idea that magnetic fields can direct an electron beam, just as lenses direct light in an optical microscope. In a transmission electron microscope, a hot tungsten element produces electrons. An electron gun then accelerates them with a potential difference, giving the beam...

preparation of samples for electron microscopy

preparation-of-samples-for-electron-microscopy

Electron Microscopy Sample Prep Methods

Electron microscopy sample prep methods help biological samples survive imaging in TEM and SEM. Before a specimen can be viewed, it must be fixed, or stabilized, so the electron beam does not damage it. It also must be dried well, or desiccated, because the microscope uses a vacuum. Fixation should happen as quickly as possible. Once a sample leaves its natural environment, its properties begin to change. In tissue samples, oxygen levels can drop and change the appearance of mitochondria. That...

immunogold electron microscopy

Immunogold Labeling in Electron Microscopy

Immunogold labeling in electron microscopy uses antibodies and tiny gold particles to find specific proteins in cells and tissues. The gold particles are very electron-dense, which means they show up clearly in electron microscope images. This gives researchers a high-resolution way to see where proteins are located and to compare their amounts under different stimulation conditions. The method can reveal proteins on the cell surface and inside cells. It has been used to study proteins...

cryo-electron microscopy

Cryo-EM for Native Biomolecule Imaging

Cryo-EM, or cryo-electron microscopy, lets scientists image biomolecules in their frozen, native state. It avoids the dehydration, fixation, and staining used in conventional electron microscopy, which can distort samples and create artifacts. It also reduces damage from the electron beam by using gentler imaging conditions. This method is useful when other structure tools have limits. X-ray diffraction needs a molecule to form a crystal, and that is not always possible. Even when...

electron microscope tomography and single-particle reconstruction

electron-microscope-tomography-and-single-particle-reconstruction

3D Imaging with Electron Microscopy

Transmission electron microscopy (TEM) can build 3D images of biological samples. It does this with electron microscope tomography and single-particle reconstruction. Tomography can show cell parts or small cells in vivo, while single-particle reconstruction is used for macromolecules and macromolecular complexes in vitro only. Electron tomography can be done in TEM or in STEM, which stands for scanning transmission electron microscopy. STEM is mainly used for thick biological specimens. It...

key terms and concepts

Learn how fluorescence microscopes use fluorochromes and antibody staining to reveal pathogens, cells, and cell structures through direct and indirect immunofluorescence.

Fluorescent Antibody Staining in Cells | JoVE K12

cell biology

JoVE Core Cell Biology illustrates complex cellular processes in easy-to-understand yet comprehensive animated video lessons. This collection focuses on the essential components and functions of cells, including organelles and membranes, cellular transport, and cell energetics. It is complemented by scientist-in-action videos that demonstrate the application of cell biology in real-world research experiments.

Fluorescent Antibody Staining in Cells

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