2 - INTRODUCTION TO CELL CULTURE

Abstract

This chapter provides an overview of cell culture. Cell culture requires less space, is less expensive, and is more convenient than the use of animals or eggs, although eggs are still the method of choice in the large-scale preparation of influenza virus vaccines. Cultures of animal cells are usually divided into three classes: (1) primary cells, (2) cell strains, and (3) cell lines. The ultimate source of cells for cell culture is the intact animal. The cells may be obtained from various organs and tissues of embryonic, infant, or adult origin. The cells thus obtained may be normal or cancerous. Regardless of their source, cultures obtained directly from the animal's organs and tissues, are referred to as primary cell cultures. Primary cell cultures retain some of the characteristics of the tissue from which they were derived and usually contain more than one cell type. With a few exceptions, cells in culture can be classified into two general morphological types. Fibroblast-like cells are thin and elongated, while epithelial-like cells are polygonal in shape and tend to form sheets. Upon serial transfers of primary cells, a gradual selection may occur until a particular cell type becomes predominant. If these cells continue to grow at a constant rate over successive passages, these primary cells are referred to as a cell strain. Cell lines that have been derived from tumors often do not exhibit contact-inhibition, but rather continue to pile-up.