Carcinoma antigen 125 (CA 125) is overexpressed in ovarian cancer and antibodies against it are widely employed for diagnostic purposes. The rarity of CA 125 antigenic domains and its highly glycosylated structure, however, is a problem that may prevent immunized mice from developing a diversified population of anti-CA 125 antibodies. In this study a prime-boost strategy, which potentially could augment the humoral immune responses against rare and poorly immunogenic determinants, was used for immunization of mice and monoclonal antibodies (mAbs) were produced by hybridoma technology. Reactivity of mAbs was then assessed by ELISA, western blotting, immunoprecipitation, immunohistochemistry and immunofluorescence staining of OVCAR-3 cell line. Altogether, 10 clones were produced, 3 of which had IgG isotype and the rest were IgM. Two-third of clones recognized cognate antigen in fixed and living cells and had strong immunoreactivity in IHC staining. In Western blotting, our antibodies recognized CA 125 as high molecular weight antigen mostly migrated in the 3% stacking gel. Immunoprecipitation of OVCAR-3 cell lysate by mAbs resulted in a very similar migration pattern that reconfirmed their specificities. The mAbs produced in this study are invaluable tools in diagnosis and research fields for assessment of CA 125 expression in cancerous ovarian tissues.

Immunohistochemistry (IHC) is a process of selectively imaging antigens in cells or tissue sections by exploiting antibody specificity. This technique is widely used in diagnostic pathology and research experiments for tracking specific molecular markers characteristic of a particular cell type or cellular events such as cancerous cell development, cell proliferation, or apoptosis. Visualizing the target antigen following an antibody-antigen interaction is accomplished by different detection systems. In the simplest instance, primary antibody directly conjugated to an enzyme is responsible for both specifically binding to the antigen and catalyzing a color-producing reaction. Alternatively, complex detection systems could be designed to profoundly improve minimal detection level of the antigen. During the past years, there has been a considerable improvement in designing and introduction of new and highly sensitive detection systems. The choice of an IHC detection system is a compromise of a variety of variables including desired sensitivity, cost, and the time needed for an IHC staining to be performed. This chapter covers the immunohistochemistry detection systems with emphasis on their principle, history, advantages, and limitations and delineates factors needed to be considered for choosing an appropriate detection system for IHC applications.

Here we introduce novel optical properties and accurate sensitivity of Quantum dot (QD)-based detection system for tracking the breast cancer marker, HER2. QD525 was used to detect HER2 using home-made HER2-specific monoclonal antibodies in fixed and living HER2(+) SKBR-3 cell line and breast cancer tissues. Additionally, we compared fluorescence intensity (FI), photostability and staining index (SI) of QD525 signals at different exposure times and two excitation wavelengths with those of the conventional organic dye, FITC. Labeling signals of QD525 in both fixed and living breast cancer cells and tissue preparations were found to be significantly higher than those of FITC at 460-495 nm excitation wavelengths. Interestingly, when excited at 330-385 nm, the superiority of QD525 was more highlighted with at least 4-5 fold higher FI and SI compared to FITC. Moreover, QDs exhibited exceptional photostability during continuous illumination of cancerous cells and tissues, while FITC signal faded very quickly. QDs can be used as sensitive reporters for in situ detection of tumor markers which in turn could be viewed as a novel approach for early detection of cancers. To take comprehensive advantage of QDs, it is necessary that their optimal excitation wavelength is employed.

Introduction Placenta is a complex organ that plays a significant role in the maintenance of pregnancy health. It is a dynamic organ that undergoes dramatic changes in growth and development at different stages of gestation. In the first-trimester, the conceptus develops in a low oxygen environment that favors organogenesis in the embryo and cell proliferation and angiogenesis in the placenta; later in pregnancy, higher oxygen concentration is required to support the rapid growth of the fetus. This oxygen transition, which appears unique to the human placenta, must be finely tuned through successive rounds of protein signature alterations. This study compares placental proteome in normal first-trimester (FT) and term human placentas (TP). Methods Normal human first-trimester and term placental samples were collected and differentially expressed proteins were identified using two-dimensional liquid chromatography-tandem mass spectrometry. Results Despite the overall similarities, 120 proteins were differently expressed in first and term placentas. Out of these, 72 were up-regulated and 48 were down-regulated in the first when compared with the full term placentas. Twenty out of 120 differently expressed proteins were sequenced, among them seven showed increased (GRP78, PDIA3, ENOA, ECH1, PRDX4, ERP29, ECHM), eleven decreased (TRFE, ALBU, K2C1, ACTG, CSH2, PRDX2, FABP5, HBG1, FABP4, K2C8, K1C9) expression in first-trimester compared to the full-term placentas and two proteins exclusively expressed in first-trimester placentas (MESD, MYDGF). Conclusion According to Reactome and PANTHER softwares, these proteins were mostly involved in response to chemical stimulus and stress, regulation of biological quality, programmed cell death, hemostatic and catabolic processes, protein folding, cellular oxidant detoxification, coagulation and retina homeostasis. Elucidation of alteration in protein signature during placental development would provide researchers with a better understanding of the critical biological processes of placentogenesis and delineate proteins involved in regulation of placental function during development.

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