A Single Simple Procedure for Dewaxing,Hydration and Heat-Induced Epitope Retrieval (HIER) for Immunohistochemistry in Formalin-Fixed Paraffin-Embedded Tissue

Heat-induced epitope retrieval (HIER) is widely used for immunohistochemistry on formalin-fixed paraffin-embedded tissue and includes temperatures well above the melting point of paraffin. We therefore tested whether traditional xylene-based removal of paraffin is required on sections from paraffin-embedded tissue, when HIER is performed by vigorous boiling in 10 mM Tris/0.5 mM EGTA-buffer (pH=9). Immunohistochemical results using HIER with or without prior dewaxing in xylene were evaluated using 7 primary antibodies targeting proteins located in the cytosol, intracellular vesicles and plasma membrane. No effect of omitting prior dewaxing was observed on staining pattern. Semiquantitative analysis did not show HIER to influence the intensity of labelling consistently. Consequently, quantification of immune labelling intensity using fluorescent secondary antibodies was performed at 5 dilutions of primary antibody with and without prior dewaxing in xylene. No effect of omitting prior dewaxing on signal intensity was detectable indicating similar immunoreactivity in dewaxed and non-dewaxed sections. The intensity of staining the nucleus with the DNA-stain ToPro3 was similarly unaffected by omission of dewaxing in xylene.In conclusion, the HIER procedure described and tested can be used as a single procedure enabling dewaxing, hydration and epitope retrieval for immunohistochemistry in formalin-fixed paraffin-embedded tissue.Key words: Immunolabelling, antibodies, histology, protein localization, HIER     

Tape transfer sectioning of tissue microarrays introduces nonspecific immunohistochemical staining artifacts

Abstract

Tissue microarrays place tens to hundreds of formalin fixed, paraffin embedded tissue cores into a paraffin block in a systematic grid pattern that permits their simultaneous evaluation in a single section. The fragmented nature of the tissue cores often makes sectioning of tissue microarrays difficult so that the resulting disks of tissue lose their shape, fracture or fall out of the paraffin section altogether. We have evaluated an alternative sectioning protocol for stabilizing the tissue microarray surface by placing an adhesive tape “window” over the face of the paraffin block prior to sectioning. Once sectioned, the tape/sections are transferred directly onto coated microscope slides, thereby avoiding routine floating of sections on a water bath. After sectioning with either the tape transfer or standard protocols, slides were stained either using hematoxylin and eosin or immunohistochemistry using antibodies to S-100 protein and the tissue specific antigens, keratin (AE1/3) and the leukocyte common antigen CD45. We found that the tape method produced thicker sections that were darker and more densely packed with loss of tissue definition compared to sections prepared using water bath flotation. Quantitative image analysis of immunohistochemical staining demonstrated that the tape method produced a higher incidence of nonspecific staining, which raised the potential for false positive staining.     

Fixation, processing, and immunochemical reagent effects on preservation of T-lymphocyte surface membrane antigens in paraffin-embedded tissue

Fixatives, fixation additives, paraffin processing reagents, and immunochemical reagents were investigated for effects on preservation of T-lymphocyte surface membrane antigens CD3, CD4, and CD8 in human tonsil. Individual reagent effects were assessed in frozen sections by use of monoclonal antibodies and this information was used to optimize T-cell immunostaining in paraffin sections. Harmful factors were fixation delay, fixation at acid pH, fixation and processing at temperatures above 4 degrees C, hot paraffin wax, proteolytic enzymes, methanolic hydrogen peroxide, Triton X-100, and prolonged iodine treatment. Optimal T-cell demonstration in paraffin sections followed tissue fixation in periodate-lysine-paraformaldehyde dichromate at 4 degrees C, pH 7.5; processing through isopropanol, then xylene or chloroform, at 4 degrees C; and embedding in low melting point wax at 45-50 degrees C. Graded antigen stability occurred: CD3 most stable, CD8 least, and CD4 intermediate. CD4 and CD8 antigen preservation in paraffin sections required critical optimal tissue handling. CD3 was more stable and was also demonstrated in tissue fixed in commercial formalin, glutaraldehyde, and Bouin's fluid when fixation and processing conditions were optimized for pH and temperature. Of the fixation additives studied, polyethylene glycol and several potassium and magnesium salts enhanced immunostaining, whereas calcium chloride and lidocaine were deleterious.     

Raman spectroscopic evaluation of efficacy of current paraffin wax section dewaxing agents.

During a spectroscopic study to identify biochemical changes in cervical tissue with the onset of carcinogenesis, residual paraffin wax contributions were observed on almost all dewaxed formalin-fixed paraffin-processed (FFPP) tissue sections examined. Subsequently, the present study was formulated to evaluate the efficacy of current dewaxing agents using Raman spectroscopy. Three cervical FFPP sections were subjected to each of the protocols. Sections were dewaxed using four common dewaxing protocols, namely, xylene, Histoclear, heat-mediated antigen retrieval (HMAR) using xylene and citrate buffer, and Trilogy (combined deparaffinization and unmasking of antigens). The potential for hexane as a dewaxing agent was also evaluated. Sections were dewaxed in multiple dewaxing cycles using xylene, Histoclear, and hexane. Residual paraffin wax contributions remained at 1062 cm(-1), 1296 cm(-1), and 1441 cm(-1). HMAR using xylene and citrate buffer, and HMAR using Trilogy, showed a similar efficacy, resulting in incomplete removal of wax. Hexane was shown to be the most effective dewaxing agent, resulting in almost complete removal of wax. Immunohistochemistry was carried out on dewaxed slides, and those dewaxed with hexane displayed a stronger positivity (approximately 28%). Implications for histopathology and immunohistochemistry are considered, as well as problems that residual wax poses for spectroscopic evaluation of dewaxed FFPP sections with a view to disease diagnosis.     

Phenotypic differences between red pulp capillary and sinusoidal endothelia help localizing the open splenic circulation in humans

The distribution of capillaries, sinuses and larger vessels was investigated by immunohistology in paraffin sections of 12 adult human spleens using a panel of antibodies. Double staining for CD34 and CD141 (thrombomodulin) revealed that capillary endothelia in the cords of the splenic red pulp and at the surface of follicles were CD34⁺CD141⁻, while red pulp sinus endothelia had the phenotype CD34⁻CD141⁺. Only in the direct vicinity of splenic follicles did sinus endothelial cells exhibit both antigens. Thus, splenic sinuses do not replace conventional capillaries, but exist in addition to such vessels. The endothelium in arterioles, venules and larger arteries and veins was uniformly CD34⁺CD141⁺. Anti-CD34 and anti-CD141 both additionally reacted with different types of splenic stromal cells. Differential staining of capillaries and sinuses may permit a three-dimensional reconstruction of serial sections to unequivocally delineate the “open” and “closed” splenic circulation in humans.     

Application of cryo-compatible antibodies to human placenta paraffin sections

The hepes-glutamic acid buffer-mediated organic solvent protection effect (HOPE) -fixation and paraffin embedding technique has been described to expand possibilities for immuno-labellings due to low denaturation of proteins. In this study, the issue was addressed as to whether the HOPE technique could be a useful tool in placenta tissue-based studies when only cryo-compatible antibodies are available. Such antibodies can be used on cryostat sections only, giving results of considerably inferior morphological detail as compared to routinely fixed paraffin embedded tissue sections. Commercially available, only cryo-compatible, monoclonal antibodies against a conformational epitope of HLA-G (clone MEM-G/9) and leukocyte differentiation antigens CD56, CD163 and CD34 III were selected and applied to frozen sections, routinely formalin-fixed and HOPE-fixed paraffin sections. All tested antibodies immunolocalized their antigen on cryo sections and on HOPE-fixed but not formalin-fixed paraffin sections. The HOPE technique provides an excellent preservation of protein antigenicity together with well presented morphological details in paraffin embedded placenta tissues. The detection of native or conformation-dependent epitopes in paraffin sections expands the immunolocalization possibilities in placenta research and reproductive immunology.     

植物组织石蜡切片的扫描电镜观察方法研究

石蜡切片的扫描电镜观察法有其独到之处:集光镜和扫捕电镜特长于一体,在大量的石蜡切片光镜观察的基础上,挑选具有研究线索的切片,采用此法转移到扫描电镜下作高分辩研究,既可普查切片全貌,又可处得切片中亚微结构的三维图像,这对结构的准确分辩十分有利,且便于作连续切片观察。本文简要介绍这一实验技术。     

Comparison of fine needle aspiration biopsy and paraffin embedded tissue sections for measuring AgNOR proteins

Abstract

Paraffin embedded tissue sections and fine needle aspiration biopsy (FNAB) are important methods for diagnosis. We compared thyroid tissue obtained by FNAB to paraffin embedded sections to determine whether there were differences in detection of the amounts of argyrophilic nucleolar organizing region (AgNOR) proteins. Twenty-two patients with papillary thyroid carcinoma were included in the study. Slides were prepared with both FNAB tissue and 3 μm sections of paraffin embedded tissue, and stained for AgNOR. One hundred nuclei per individual were evaluated; total AgNOR number/nucleus (TAn/TNn) and total AgNOR area/nuclear area (TAa/TNa) of individual cells were determined. Mean TAn/TNn and TAa/TNa values were 4.800 ± 1.118 and 13.382 ± 2.612, respectively, for FNAB samples; corresponding values were 2.406 ± 0.649 and 8.49 ± 0.893, respectively, for paraffin embedded sections. The differences between FNAB materials and paraffin embedded tissue sections were significant for the mean TAn/TNn and TAa/TNa values. Significant differences in the amounts of AgNOR protein detected were found between FNAB and paraffin embedded tissue sections.     

Development, maturation and subsequent activation of follicular dendritic cells (FDC): immunohistochemical observation of human fetal and adult lymph nodes

To elucidate the processes involved in development and activation of human follicular dendritic cells (FDC), immunohistochemistry was performed on paraffin sections of fetal lymph nodes (FLN) obtained from archived autopsy material, and of adult reactive lymph nodes (ARLNs) excised for diagnostic purpose, using a panel of antibodies. Our study showed that tiny clusters of CNA.42⁺ KiM4p⁺ cells, surrounded by some B-lymphocytes, initially arose in the cortical area of underdeveloped FLN around the 20th gestational week. No co-expression of CD21 and CD35 was found. In the relatively developed FLN of the same gestational age, small eddies of immature FDC, which expressed CD21, CD35, and nerve growth factor receptor (NGFR), as well as CNA.42 and KiM4p, were observed within ill-defined aggregations of B-lymphocytes. As gestation progressed, more B-lymphocytes assembled in a compact manner and formed primary lymphoid follicles containing an extending web of mature FDC, which expressed CNA.42, KiM4p, CD21, CD35, NGFR, and sometimes CD23 and X-11. In well-developed secondary follicles of ARLNs, activated FDC expressed additional molecules such as CD55, CD106, and S100α. Our observations identified the processes of phenotypic alteration of human FDC and established practical indicators determining their developmental stage and functional phase.     

流式细胞仪分选人外周血T淋巴细胞的方法建立与评价

目的:利用流式细胞仪同时分离外人周血单个核细胞中T淋巴细胞并检测其分离纯度及存活率。方法:本文采用流式细胞仪同时分选人外周血CD4~+、CD8~+T淋巴细胞为例,推而广之,采用人外周血淋巴细胞分离液梯度离心法制备外周血单个核细胞,采用流式细胞仪同时分选CD4~+、CD8~+T淋巴细胞,分离细胞再通过流式细胞仪回测其分离纯度并通过台盼蓝染色检测分离细胞的存活率。结果:采用此方法能有效人外周血细胞CD4~+、CD8~+T淋巴细胞,分选前CD4~+淋巴细胞纯度为(50.5±11.5)%、CD8~+T淋巴细胞纯度为纯度为(15.4±7.1)%;分选后CD4~+T淋巴细胞纯度为(94.3±1.3)%、CD8~+T淋巴细胞纯度为(93.6±1.6)%;分选后CD4~+T淋巴细胞存活率为(95.3±1.8)%,CD8~+T淋巴细胞存活率为(94.8±1.5)%,细胞的形态完整。结论:采用人外周血淋巴细胞分离液梯度离心法制备外周血单个核细胞后利用流式细胞仪分选的方法能够高效、快速的分离人外周血CD4~+、CD8~+T淋巴细胞,且存活率高,为进一步研究其功能提供了保证。采用不同的荧光抗体标记其他淋巴细胞亚群,也能高效、快速的分离出细胞。     

Biofilm of Pseudomonas C12B on glass support as catalytic agent for continuous SDS removal

The purpose of this work was to investigate the biodegradation of Sodium dodecylsulphate, a common surfactant used in commercial detergent formulations, by immobilized cells of the surfactant-degrading bacterium Pseudomonas C12B. Cells were immobilized by adsorption on porous glass beads with either unmodified or silanized surface. Data showed a direct relation between the SDS concentration in the medium and formation of the biofilm on glass beads. Bioreactors with Pseudomonas C12B cells immobilized on both types of porous glass beads were prepared. Both types showed equivalent efficiency to remove SDS. This biocatalyst was also effective to remove anionic surfactants from commercial dishwashing liquid (Jar) and shampoo (Clear) under continuous operation.     

冰冻切片与石蜡切片对乳腺肿瘤的诊断价值研究

目的:分析和比较冰冻切片与石蜡切片对乳腺肿瘤的诊断价值。方法:选取480例新鲜乳腺标本,将其制成冰冻切片以及石蜡切片,根据诊断结果进行对比分析,评价乳腺肿瘤的冰冻切片与石蜡切片的对乳腺肿瘤的诊断价值。结果:经石蜡切片诊断乳腺良性肿瘤277例,占57.71%,良性肿瘤中以乳腺纤维瘤诊断居多;经石蜡切片诊断乳腺恶性肿瘤203例,占42.29%,以乳腺浸润性导管癌居多。冰冻切片诊断乳腺良性肿瘤279例,占58.13%;恶性肿瘤195例,占40.62%;延迟诊断6例,占1.25%。以石蜡切片诊断结果为金标准,冰冻切片诊断乳腺良性肿瘤的准确率为98.56%(273/277),诊断恶性肿瘤的准确率为95.07%(193/203),假阳性率为0.72%(2/277),假阴性率为2.96%(6/203),冰冻切片与石蜡切片诊断乳腺肿瘤的结果具有显著一致性,K值为0.965(P0.05)。结论:冰冻切片与石蜡切片诊断乳腺肿瘤的符合率较高,可作为术中快速病理检测的手段,但该种切片方式存在少量延迟诊断,多与术者操作经验有关,故术中应注重制片过程,提高冰冻切片质量。     

Immunohistochemistry: paraffin sections using the Vectastain ABC kit from vector labs

Immunohistochemistry (IHC) is a valuable technique utilized to localize/visualize protein expression in a mounted tissue section using specific antibodies. There are two methods: the direct and indirect method. In this experiment, we will only describe the use of indirect IHC staining. Indirect IHC staining utilizes highly specific primary and biotin-conjugated secondary antibodies. Primary antibodies are utilized to discretely identify proteins of interest by binding to a specific epitope, while secondary antibodies subtract for non-specific background staining and amplify signal by forming complexes to the primary antibody. Slides can either be generated from frozen sections, or paraffin embedded sections mounted on glass slides. In this protocol, we discuss the preparation of paraffin-embedded sections by dewaxing, hydration using an alcohol gradient, heat induced antigen retrieval, and blocking of endogenous peroxidase activity and non-specific binding sites. Some sections are then stained with antibodies specific for T cell marker CD8 and while others are stained for tyrosine hydroxylase. The slides are subsequently treated with appropriate secondary antibodies conjugated to biotin, then developed utilizing avidin-conjugated horseradish peroxidase (HRP) with Diaminiobenzidine (DAB) as substrate. Following development, the slides are counterstained for contrast, and mounted under coverslips with permount. After adequate drying, these slides are then ready for imaging.     

Commercial polyclonal and monoclonal histostaining PAP kits

Summary Universal, polyclonal and monoclonal immunoperoxidase staining kits from BioGenex, Dako and Ortho were employed for the localization of antigens such as gastrin, prostate specific antigen, IgA, IgG, AFP and CEA in histological sections from formaldehyde fixed and paraffin embedded human specimens. The kit components were controlled by immunohistological and serological assays and were also compared with self-prepared reagents. In connection with specific primary antibodies, universal/basic kits gave reliable localization of defined antigens. The optimal concentration of the primary antibodies had to be established by dilution experiments. In the case of polyclonal kits, typical antigen localization was obtained in selected tissue sections with all the respective kits. CEA kits also stained strongly NCA molecules present in organs such as colon, stomach and liver. BioGenex polyclonal kits gave almost stronger stainings than kits from Dako and Ortho. Irrespective of which kit from different commercial sources is used, development of peroxidase activity with AEC/H₂O₂ often had to be stopped far below the recommended incubation time of 40 min or overstaining with color change from reddish to muddy green occurred. The latter was attributed to insufficiently balanced kit reagents, an interpretation wich was supported by quantitative serological studies. Sensitivity of immunohistological reactivity was much enhanced by pretreatment of tissue sections with Pronase. Thus, stronger immunostainings and larger numbers of positive cells were detected than in conventionally rehydrated sections. Incubation of sections with self-prepared primary antibodies, linking antibodies and PAP complexes gave essentially the same antigen localization as with commercial kits, but antibodies isolated by our affinity chromatography led to a better staining contrast with absence of nonspecific background. The advantage of monoclonal over polyclonal kits was the background-free staining of sections. Other-wise, antigens were localized in the same cell types, although cellular reactivity was usually less intense than with polyclonal antibodies. This, however, could be overcome by Pronase treatment of the sections prior to incubation.     

Immunohistochemistry on Paraffin Sections of Mouse Epidermis Using Fluorescent Antibodies

In the epidermis, immunohistochemistry is an efficient means of localizing specific proteins to their relative expression compartment; namely the basal, suprabasal, and stratum corneum layers. The precise localization within the epidermis of a particular protein lends clues toward its functional role within the epidermis. In this chapter, we describe a reliable method for immunolocalization within the epidermis modified for both frozen and paraffin sections that we use very routinely in our laboratory. Paraffin sections generally provide much better morphology, hence, superior results and photographs; however, not all antibodies will work with the harsh fixation and treatment involved in their processing. Therefore, the protocol for frozen sectioning is also included. Within paraffin sectioning, two fixation protocols are described (Bouin''s and paraformaldehyde); the choice of fixative will be directly related to the antibody specifications and may require another fixing method.Download video file.^{(94M, mov)}     

A simple and rapid microwave-assisted hematoxylin and eosin staining method using 1,1,1 trichloroethane as a dewaxing and a clearing agent

The use and practicability of microwave-assisted staining procedures in routine histopathology has been well established for more than 17 years. In the study reported here, we aimed to examine an alternative approach that would shorten the duration of dewaxing and clearing steps of hematoxylin and eosin (H & E) staining of paraffin sections by using a microwave oven. Although xylene is one of the most popular dewaxing and clearing agents, its flammability restricts its use in a microwave oven; thus we preferred 1,1,1 trichloroethane, which is not flammable, as the dewaxing and clearing agent in the present study. In Group I and Group II (control groups), intestine was processed with xylene and 1,1,1 trichloroethane, respectively. The sections were then stained with H & E according to the conventional staining protocol at room temperature and subdivided into two groups according to the duration of dewaxing and clearing in xylene. In Groups III and IV (experimental groups) similar tissues were processed with xylene and 1,1,1 trichloroethane, respectively; however, sections from these groups were divided into four subgroups to study the period required for dewaxing and clearing in 1,1,1 trichloroethane, then stained with H & E in the microwave oven at 360 W for 30 sec. Our conventional H & E staining procedure, which includes dewaxing, staining and clearing of sections, requires approximately 90 min, while our method using 1,1,1 trichloroethane and microwave heating required only 2 min. Our alternative method for H & E staining not only reduced the procedure time significantly, but also yielded staining quality equal or superior to those stained the conventional way. Our results suggest that 1,1,1 trichloroethane can be used effectively and safely as a dewaxing and clearing agent for H & E staining in a microwave oven.     

CD133 immunomagnetic separation: effectiveness of the method for CD133(+) isolation from umbilical cord blood

Background aimsUmbilical cord blood (UCB) is a rich source of stem cells, the characterization and isolation of which requires specific stem cell markers and reliable and reproducible protocols.MethodsWe assessed CD133 isolation in 39 UCB samples, using a commercial immunomagnetic cell-sorting protocol, and, because of its non-reproducibility, we applied optimized protocols in an effort to improve it. These included extra-labeling of the selected CD133⁺ subpopulation and indirect labeling using anti-phycoerythrin (PE) microbeads, goat anti-mouse IgG microbeads or a combination of both. The CD34 isolation was used as a control.ResultsThe mononuclear cell fraction expressed 0.53 ± 0.06% CD133. The corresponding value for CD34 was 1.64 ± 0.15%. Following the manufacturer's instructions, the CD34 isolation resulted in a population expressing 93 ± 1.25% CD34 while, after the corresponding process, CD133⁺ expression ranged from 10% to 85% (median 60%). The optimized isolation protocols did not result in improved CD133⁺ yield. The variation in the purity of the CD133 population cannot be attributed to the different clones of CD133 used, because they do not cross-block, while other factors such as glycosylation, which could possibly interfere, do not apply in normal hematopoietic stem cells (HSC).ConclusionsCD34 isolation by the immunomagnetic method results in highly pure CD34⁺ population, while the efficient and reproducible yield of a pure CD133⁺ population is not feasible. Therefore quantification of the positive cells should follow each isolation procedure in order to confirm the number of CD133⁺ cells.     

A simple and rapid microwave-assisted hematoxylin and eosin staining method using 1,1,1 trichloroethane as a dewaxing and a clearing agent

The use and practicability of microwave-assisted staining procedures in routine histopathology has been well established for more than 17 years. In the study reported here, we aimed to examine an alternative approach that would shorten the duration of dewaxing and clearing steps of hematoxylin and eosin (H & E) staining of paraffin sections by using a microwave oven. Although xylene is one of the most popular dewaxing and clearing agents, its flammability restricts its use in a microwave oven; thus we preferred 1,1,1 trichloroethane, which is not flammable, as the dewaxing and clearing agent in the present study. In Group I and Group II (control groups), intestine was processed with xylene and 1,1,1 trichloroethane, respectively. The sections were then stained with H & E according to the conventional staining protocol at room temperature and subdivided into two groups according to the duration of dewaxing and clearing in xylene. In Groups III and IV (experimental groups) similar tissues were processed with xylene and 1,1,1 trichloroethane, respectively; however, sections from these groups were divided into four subgroups to study the period required for dewaxing and clearing in 1,1,1 trichloroethane, then stained with H & E in the microwave oven at 360 W for 30 sec. Our conventional H & E staining procedure, which includes dewaxing, staining and clearing of sections, requires approximately 90 min, while our method using 1,1,1 trichloroethane and microwave heating required only 2 min. Our alternative method for H & E staining not only reduced the procedure time significantly, but also yielded staining quality equal or superior to those stained the conventional way. Our results suggest that 1,1,1 trichloroethane can be used effectively and safely as a dewaxing and clearing agent for H & E staining in a microwave oven.     

A simple and rapid microwave-assisted hematoxylin and eosin staining method using 1,1,1 trichloroethane as a dewaxing and a clearing agent.

The use and practicability of microwave-assisted staining procedures in routine histopathology has been well established for more than 17 years. In the study reported here, we aimed to examine an alternative approach that would shorten the duration of dewaxing and clearing steps of hematoxylin and eosin (H & E) staining of paraffin sections by using a microwave oven. Although xylene is one of the most popular dewaxing and clearing agents, its flammability restricts its use in a microwave oven; thus we preferred 1,1,1 trichloroethane, which is not flammable, as the dewaxing and clearing agent in the present study. In Group I and Group II (control groups), intestine was processed with xylene and 1,1,1 trichloroethane, respectively. The sections were then stained with H & E according to the conventional staining protocol at room temperature and subdivided into two groups according to the duration of dewaxing and clearing in xylene. In Groups III and IV (experimental groups) similar tissues were processed with xylene and 1,1,1 trichloroethane, respectively; however, sections from these groups were divided into four subgroups to study the period required for dewaxing and clearing in 1,1,1 trichloroethane, then stained with H & E in the microwave oven at 360 W for 30 sec. Our conventional H & E staining procedure, which includes dewaxing, staining and clearing of sections, requires approximately 90 min, while our method using 1,1,1 trichloroethane and microwave heating required only 2 min. Our alternative method for H & E staining not only reduced the procedure time significantly, but also yielded staining quality equal or superior to those stained the conventional way. Our results suggest that 1,1,1 trichloroethane can be used effectively and safely as a dewaxing and clearing agent for H & E staining in a microwave oven.