Techniques for establishing human epithelial cell cultures: sensitivity of cell lines for propagation of herpesviruses

Establishment of a convenient system for the long-term culture and study of non-neoplastic human salivary gland epithelial cells

Epithelial cells appear to play an important role in the initiation and maintenance of autoimmune lesions in the salivary glands of patients with Sjogren's syndrome. Therefore, the detailed study of immunological function of salivary gland epithelial cells (SGEC) may provide useful information for the understanding of Sjögren's syndrome pathogenesis. In this report we aimed to formulate a protocol for the establishment of human non-neoplastic SGEC lines as a tool for the study of the physiology and pathophysiology of these cells. Pointing towards a practical approach, we sought to establish SGEC lines from quite a limited amount of biopsy tissue obtained during the diagnostic evaluation of patients. Herein, the favorable conditions for the long-term maintenance of human non-neoplastic SGEC lines are presented and involve the successive application of a serum-containing and a serum-free culture medium, supplemented with essential epithelial growth factors. This protocol has been found reliable and convenient, as attested by the reproducible establishment of non-neoplastic SGEC lines. The analysis of SGEC phenotypic features, as well as a coculture system for the study of interactions between epithelial cells and lymphocytes, are also described. Such techniques may provide valuable means for the functional and molecular investigation of human SGEC and particularly for the study of Sjögren's syndrome and other disorders of glandular epithelia.

A simple and reliable technique for culturing of human oral keratinocytes and fibroblasts

Cultures of non-malignant oral cells are needed for many applications in the field of oral biology. We describe an efficient and rapid method for the culture of both keratinocytes and fibroblasts isolated from oral tissue, uvulas from patients undergoing reconstructive surgery and non-cancerous tissue from oral cancer patients. High cell yields with a high purity could be obtained. The technique is described in detail with respect to isolation of the cell types, the best way to propagate for over 5 passages and to measure cell proliferation in a colorimetric assay. Culture was successful in over 80% of cases for keratinocytes and over 63% for fibroblasts. Problems encountered were the risk of microbiological infection, the size of the specimen and the type of culture medium used. The potential applications of these primary cell cultures are mentioned.

Establishment of primary cultures of rat and human parotid epithelial cells for transfection experiments

The molecular mechanisms that regulate the synthesis of salivary proteins are unknown. The paucity of homogeneous cell populations of parotid acinar cells has become a limiting factor for such a study. Therefore, the establishment of immortalized clones of acinar cells is essential. This study has established primary cultures of rat and human parotid epithelial cells that are suitable for transfection with plasmid vectors, pSV2, pSV3, and pSV5 to generate immortalized cells in vitro. Among various techniques used, the rat and human parotid tissue or cellular clumps when restrained in chicken plasma clot allowed the outgrowth of epithelial cells that maintained epithelial cell morphology for over 4 wk. However, the initial growth requirements for rat and human parotid cells were different. The presence of 10% heat inactivated fetal bovine serum in supplemented MCDB-LB medium was essential for the outgrowth of rat parotid epithelial cells, but this was not needed for the outgrowth of human parotid epithelial cells. The growth of both human and rat parotid epithelial cells can be maintained in serum-free supplemented MCDB-LB. These primary cultures contained amylase-producing cells as demonstrated by immunofluorescent technique, and they were transfected with pSV2, pSV3, and pSV5 using primarily the calcium phosphate-DNA co-precipitation technique. After initial extensive cell death, many cells with epithelial cell morphology survived.

Acquired immunodeficiency syndrome and Epstein-Barr virus

Epstein-Barr virus is an important aetiological factor in certain HIV-related syndromes, with its opportunist expression related to the level of host immunodeficiency. In asymptomatic people co-infected with HIV, EBV activity is reflected by increased viral shedding and rises in anti-EBV titres; as immunodeficiency ensues EBV manifests as epithelial hyperproliferation in OHL, and later as B-cell lymphoma in AIDS. The suggested role of EBV as a co-factor in the progression of HIV infection and development of AIDS has not been established, although another herpesvirus, cytomegalovirus, might play such a role. Advances in our understanding of HIV regulation and its interaction with other latent (herpes) viruses should provide important molecular and pharmacological approaches to the clinical management of advanced HIV disease.