Baldwin H. Tom

Human colonic adenocarcinoma cells: I. Establishment and description of a new line

SummaryA series of human colonic epithelial cell lines have been cultured from a single patient: LS-180 the original adenocarcinoma, LS-174T a trypsinized variant, and normal colonic tissue. The malignant cells, 20 to 40 µm in diameter and oval to polygonal, exhibited characteristics of normal colonic mucosal cells, namely, abundant microvilli prominent in secretory cells, and the presence of intracytoplasmic mucin vacuoles. The cultured adenocarcinoma cells, but not normal, demonstrated neoplastic properties by producing high levels of carcinoembryonic antigen (CEA) and by the ability to be propagated in hamster cheek pouches and in immunodeprived mice. The CEA production by the newly established line LS-180 released 900 times more CEA per cell into the culture medium and bore 30 times more cell-associated material than the established line, HT-29. These cell lines may permit detection of distinctive chemical, physiological, pharmacologic, and immunologic characteristics of neoplastic colonic cells.

Purification of tumor-specific antigens. An overview of the relevance to human colon carcinoma.

Methods which dissociate intramolecular noncovalent bonds have been used to prepare soluble derivatives of cell‐surface antigens. Applications of these techniques to human colon carcinoma are underway. Continuous tissue‐culture strains derived from primary lesions were developed and shown to be composed of malignant epithelial elements. Parallel data on the preparation and activity of soluble materials in a murine model methylcholanthrene system reveal that although cultured cells are a satisfactory source for antigen extraction, they are poor targets of the immune response. The development of methods to quantitate the biologic activity of colon‐specific, soluble materials may provide indicator systems to define the antigenic determinants, to permit purification, and to serve as assays of the efficacy of immunotherapy.

Leukocyte Aggregation Test for Evaluating Cell-Mediated Immunity

Publisher Summary Cell-mediated immunity as demonstrated in vitro consists of at least three steps: recognition, proliferation, and performance. The leukocyte aggregation test (LAT) was developed to evaluate the cellular immunity of patients undergoing renal transplantation. The LAT is based upon the adhesion of host leukocytes to target cells secondary to an immunospecific recognition of donor transplantation antigens by sensitized T lymphocytes. After this event, predominantly nonimmune leukocytes are captured at the reaction foci and appear as aggregates. The reaction requires the expenditure of metabolic energy; it is dependent upon physiological temperatures and is susceptible to inhibitors of protein and RNA synthesis. The LAT has several advantages that recommend it as a routine tool for assessing cell-mediated immunity in transplant patients: (1) completion within 5 hours, (2) requirement for only 10 ml of whole blood, permitting daily testing, (3) relative resistance to immunosuppressive agents, (4) immunological specificity, and (5) sensitivity to the modulating effects of serum factors on cellular immunity.