Date of Award

7-1970

Document Type

Thesis - Restricted

Degree Name

Master of Science (MS)

Department

Biological Sciences

First Advisor

Sidney E. Grossberg

Second Advisor

Arvid L. Erlandson

Third Advisor

Bernard A. Brown

Fourth Advisor

Patricia Jameson

Abstract

A completely defined medium may be regarded as highly desirable to the adequate study of cells in culture. This was recognized early by White (1946) and by a number of more recent workers (Morton, Morgan and Parker, 1950; Waymouth, 1955; Evans et al., 1956; Eagle, Oyama and Levy, 1957) Prior to the use of defined media, the basic ingredients of a synthetic medium (salt mixture, carbohydrates, amino acids and vitamins) were always supplemented with varying amounts of undefined biological fluids, e.g., calf serum. The elimination of undefined constituents from the medium has several advantages : 1) experimental results are more reproducible ; 2) cells can be more easily classified with respect to properties and behaviour; 3,) the hazards of using serum (Lo Grippo, 1958), e.g. antiviral antibody, nonspecific viral inhibitors, and cell toxicity can be avoided; and 4) a defined medium can be altered in a controllable manner , thus providing a useful
system for the study of cell functions.

One example of an important cell function which could be better studied in a chemically defined environment is interferon production (Isaacs and Lindenman, 1957). Interferon, a host- induced protein which inhibits viral replication, (Marcus and Salb, 1966) provides the underlying basis for most examples of viral interference. It is a form of resistance not mediated by antibody, and is effective
against a variety of unrelated viruses. The usefulness of interferon (or the stimulation of interferon) for chemotherapeutic purposes depends to a great extent upon an understanding of what makes cells produce interferon. Many studies have been carried out using a variety of cell types and interferon inducers in attempts to provide an understanding of the induction, production and mechanism of action of interferon. Human cell cultures are obviously of great interest in these types of studies, however, other primate cells e.g. monkey kidney, may also be of great value, not only because monkey interferons have been shown to protect certain human cells, but also because basic similarities may exist in all primate cells with regard to interferon production and mode of action. In these types of studies (as with studies on other cell functions) the use of a controlled, defined cellular environment is important.

In most cell culture studies, including those using monkey kidney cells, the culture medium has not been defineable. There have been a few examples of cells being subcultured in chemically defined media (Evans, Bryant, Kerr and Schilling, 1964; Rappaport, 1956 and Waymouth, 1959), but these studies have usually required either very complex media or quite complicated procedures for handling the cells. An exception to this is the study by Waymouth (1959), in which rapid proliferation of L- cells was accomplished using unsupplemented Waymouth MD 752/1. Calf or other animal serum has usually been used as a supplement to the medium since it is commonly observed that the addition of serum aids in an unknown manner in the attachment and growth of cell monolayers (Bailey, 1966;, Geyer, Bennett and Rohr, 1962;1 Marr, Owen and Wilson, 1962; Todaro and Green, 1964).

Monkey kidney cells, both in primary cultures and as cell lines, have been utilized and studied extensively with regard to t heir susceptibility to a number of enteroviruses (Rambling and Davis, 1965; McQuillin, Pal and Gardner, 1961). The potential value of these cells has been showm to extend to a number of other areas of research e.g. use as plaque assay systems for group B arboviruses (Miles and Austin, 1963; Bergold and Mazzali, 1968; Stim, 1969). Other studies have been done with monkey kidney cells in regard to their interferon-producing capacities and their sensitivity to interferon. It is of interest that interferon samples in some instances have shown higher titers in certain human cell lines than in the monkey cells in which the interferon was produced, whereas protection of monkey kidney cells with human interferon has generally revealed lower titers (Isaacs, Porterfield and Baron, 1961) .

Jenkin (1970) showed that the LLC-MK-2 continuous rhesus monkey kidney cell line (Hull, Cherry and Johnson, 1956) could be maintained in Waymouth medium (Table II) supplemented with sodium oleate and bovine albmnin low in fatty acids. His method, however, required that the cells initially be established in medium containing 0.5 to 1.0% calf serum. After 24 hours the serum- supplemented medium could be removed and replaced with serum-free medium, which would support continued growth of the cells to form complete monolayers This study describes the establishment of a subline of the LLC-MK-2 cells in chemically defined medium and makes the following comparisons between the original and derived cell lines : 1) their morphology and behaviour; 2) their susceptibility to several different types of viruses; 3) their interferon-producing capacities and 4) their sensitivity to interferon.

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