• ATR
• Infrared Spectroscop
• LLC-MK2
• Sendai Virus
• Virus

This work reviews the biology of viruses, their classification, and the state of viral research, with emphasis on Sendai Virus, together with in vitro studies on LLC-MK2 cells. Because viruses are obligate intracellular pathogens, they totallydepend on cellular machinery for replication and production of new infectious particles and convert host cells into "virocells" with a transcriptional emphasis on viral replication. This dependency realizes special virus-host interactions important in viral pathogenesis and is classified by the Baltimore system, which divides viruses into seven groups according to genome type and replication strategy. Each Baltimore class has its own unique methods of replicating and exploiting host cellular machinery. Antigenic drift and shift in viruses like influenza illustrate ways in which viral evolution evades immune detection and continues posing new challenges in vaccine design.

Sendai Virus is a member of the Paramyxoviridae family and, due to different reasons, has been one of the most studied viruses. This thesis also focuses on the use of SeV in research, especially with the LLC-MK2 cell line. The LLC-MK2 cells were developed to minimize the problems of contamination and experimental variability with primary monkey kidney tissue cultures. The LLC-MK2 cell line is a very adaptive and stable cell culture; it provides a virus-free environment for studies on viral replication, cytopathic effects, and virus-host dynamics. Its applications span virus titration, plaque assays, and studies of cytopathic effects, providing a robust means to quantify viral infectivity, examine viral mutations, and extend therapeutic research.

The LLC-MK2 cell line has also played an important role in experimental oncology as a model of virus-induced oncogenesis. Stability and predictable responses to viral infection support research into how viruses may impact cellular functions that lead to the development of cancer. They do not exhibit malignant transformation under standard laboratory conditions; hence, they have proved to be a reliable model for long-term studies.

Besides cellular analysis, the document points to vibrational spectroscopy techniques-infrared and Raman spectroscopy-which allow for non-invasive monitoring of molecular changes in virus-infected cells. The biochemical changes at the time of infection are signaled by these techniques, thus creating a kind of molecular "fingerprint" distinguishing infected from uninfected cells. ATR spectroscopy is particularly well-suited for aqueous samples and avoids the issues of water absorption in IR analysis; thus, it is a technique that will enable real-time monitoring of an infection's progress. The different techniques provide fast, high-throughput analyses of viral infections and improve diagnostic precision.

The experimental procedures were elaborated on culturing LLC-MK2 cells, their infection with SeV, plaque assays, and ATR spectroscopy. Methods of this type could present standardized and reproducible procedures, thereby raising the level of reliability and precision in the area of studies of virology. In particular, ATR spectroscopy captures spectral changes related to both viral and cellular components, thus helping identify markers of infection.

This work illustrates the utility of LLC-MK2 cells in combination with vibrational spectroscopy as tools of basic research in virology. First, LLC-MK2 cells reliably develop a stable model for research on virus-host interactions, and second, vibrational spectroscopy provides real-time, precise monitoring of molecular events in cells during viral infection. Put together, these approaches could provide a leap in further understanding viral mechanisms, supporting antiviral drug development, and applying other uses in diagnostics to help in the management of viral diseases through better diagnostic tools

This work reviews the biology of viruses, their classification, and the state of viral research, with emphasis on Sendai Virus, together with in vitro studies on LLC-MK2 cells. Because viruses are obligate intracellular pathogens, they totallydepend on cellular machinery for replication and production of new infectious particles and convert host cells into "virocells" with a transcriptional emphasis on viral replication. This dependency realizes special virus-host interactions important in viral pathogenesis and is classified by the Baltimore system, which divides viruses into seven groups according to genome type and replication strategy. Each Baltimore class has its own unique methods of replicating and exploiting host cellular machinery. Antigenic drift and shift in viruses like influenza illustrate ways in which viral evolution evades immune detection and continues posing new challenges in vaccine design. Sendai Virus is a member of the Paramyxoviridae family and, due to different reasons, has been one of the most studied viruses. This thesis also focuses on the use of SeV in research, especially with the LLC-MK2 cell line. The LLC-MK2 cells were developed to minimize the problems of contamination and experimental variability with primary monkey kidney tissue cultures. The LLC-MK2 cell line is a very adaptive and stable cell culture; it provides a virus-free environment for studies on viral replication, cytopathic effects, and virus-host dynamics. Its applications span virus titration, plaque assays, and studies of cytopathic effects, providing a robust means to quantify viral infectivity, examine viral mutations, and extend therapeutic research. The LLC-MK2 cell line has also played an important role in experimental oncology as a model of virus-induced oncogenesis. Stability and predictable responses to viral infection support research into how viruses may impact cellular functions that lead to the development of cancer. They do not exhibit malignant transformation under standard laboratory conditions; hence, they have proved to be a reliable model for long-term studies. Besides cellular analysis, the document points to vibrational spectroscopy techniques-infrared and Raman spectroscopy-which allow for non-invasive monitoring of molecular changes in virus-infected cells. The biochemical changes at the time of infection are signaled by these techniques, thus creating a kind of molecular "fingerprint" distinguishing infected from uninfected cells. ATR spectroscopy is particularly well-suited for aqueous samples and avoids the issues of water absorption in IR analysis; thus, it is a technique that will enable real-time monitoring of an infection's progress. The different techniques provide fast, high-throughput analyses of viral infections and improve diagnostic precision. The experimental procedures were elaborated on culturing LLC-MK2 cells, their infection with SeV, plaque assays, and ATR spectroscopy. Methods of this type could present standardized and reproducible procedures, thereby raising the level of reliability and precision in the area of studies of virology. In particular, ATR spectroscopy captures spectral changes related to both viral and cellular components, thus helping identify markers of infection. This work illustrates the utility of LLC-MK2 cells in combination with vibrational spectroscopy as tools of basic research in virology. First, LLC-MK2 cells reliably develop a stable model for research on virus-host interactions, and second, vibrational spectroscopy provides real-time, precise monitoring of molecular events in cells during viral infection. Put together, these approaches could provide a leap in further understanding viral mechanisms, supporting antiviral drug development, and applying other uses in diagnostics to help in the management of viral diseases through better diagnostic tools