The cytochemical characteristics of populations of human lymphoblasts (CCRF-CEM cells) in continuous log-phase suspension cultures derived from the peripheral blood buffy coat of a child with acute lymphoblastic leukemia have been determined by the use of high-resolution, rapid-scanning biophysical population analysis techniques.

The human T-lymphotropic virus type-1 (HTLV-1) is the causative agent of adult T cell leukemia/lymphoma (ATL) and HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP). CD4+T cells are the main target of HTLV-1, but other cell types are known to be infected, including immature lymphocytes. Developing T cells undergo differentiation in the thymus, through migration and interaction with the thymic microenvironment, in particular with thymic epithelial cells (TEC) the major component of this three dimensional meshwork of non-lymphoid cells. Herein, we show that TEC express the receptors for HTLV-1 and can be infected by this virus through cell–cell contact and by cell-free virus suspensions. The expression of anti-apoptosis, chemokine and adhesion molecules genes are altered in HTLV-1-infected TEC, although gene expression of antigen presentation molecules remained unchanged. Furthermore, HTLV-1-infected TEC transmitted the virus to a CD4+ T cell line and to CD4+ T cells from healthy donors, during in vitro cellular co-cultures. Altogether, our data point to the possibility that the human thymic epithelial cells play a role in the establishment and progression of HTLV-1 infection, functioning as a reservoir and transmitting the virus to maturing CD4+ T lymphocytes, which in turn will cause disease in the periphery.

The morphology of human leukemic lymphoblasts (CCRF-CEM cells) maintained in continuous log-phase suspension cultures for more than one year has been studied at regular intervals with the electron microscope. During this time, minor changes in morphology have been observed, the most striking change being the appearance and persistence of very dense granules in the pars amorpha of the nuclcoli. The effects of a series of inhibitory agents have been studied but no virus particles have been observed in these or untreated CCRF-CEM cells, although the wrapping of dense cell fragments by remnants of nuclear membrane under a variety of conditions leading to cell destruction was suggested as the mechanism of formation of the "virus-mimickers" observed in these studies. Deliberate search by electron microscope and cultural studies has failed to reveal evidence of the presence of Mycoplasma in the CCRF-CEM cells or cell cultures.

A method for the cytochemical evaluation of the mechanism of action of potential metabolic inhibitors in cell culture, utilizing the rapid-scanning, high-resolution, automatically integrating biophysical instrumentation developed for cell population analyses is described. This method permits the in situ determination of the amount of DNA, RNA, and protein in individual cells in populations of heterogeneous cells, and the effects of inhibitory agents on these biosynthetic processes. The utility of the method has been demonstrated by the cytochemical evaluation of a series of inhibitory agents selected on the basis of what is known of their mechanisms of action with respect to inhibition of mitosis, synthesis of nucleic acids, or protein. The results of cytochemical analyses of populations of cells exposed to these agents agreed in general with what is known of their mechanisms of action from other studies.

Various cells from humans and animals have been established as cell lines, and their features, characteristics, and origins have been reported. Many laboratories use cell lines as model cells, which are selected to suit research purposes.We attempted to identify the ABO genotypes of 31 human leukemia and lymphoma cell lines stored in our laboratory using three methods: the PCR amplification of specific alleles (PASA), PCR-restriction fragment length polymorphism (RFLP), and the direct DNA sequencing of PCR products.We distinguished 31 human leukemia and lymphoma cell lines examined into six major ABO genotypes: A/O (A101/O01: n = 1, A101/O12: n = 4, A101/O26: n = 1, A101/O49: n = 1, A102/O01: n = 3), A/A (A101/A101: n = 1, A102/A102: n = 2), B/O (Bw29/O01: n = 1), B/B (B101/B101: n = 2), O/O (O01/O01: n = 9, O01/O02: n = 1, O01/O26: n = 1, O02/O03: n = 1), and A/B (A102/B101: n = 3).To the best of our knowledge, this is the first study to identify the ABO genotypes of various cell lines. The ABO genotypes of cell lines are important when selecting an experimental model cell for an ABO blood group study, and are essential information for cell lines. These results may be employed by research and clinical laboratories as well as in the forensic field.

Cytochemical techniques have been developed for the quantitative determination of the DNA, RNA and proteins (dry mass) in individual cells in large cell populations. These methods have been employed for the study of the effects of nitrogen mustard and actinomycin D on the nucleolar system of Ehrlich ascites cells in vivo and a line of normal mouse fibroblasts maintained in cell culture. Parallel studies on the nucleoli of individual cells have been made with ultraviolet microscopy and spectrophotometry.

Fluorescent and other studies in human breast epithelium indicate an affinity of the established pharmacalogically and therapeutically tested compound, quinacrine dihydrochloride, for nucleoli, nuclear membranes, and intranuclear granules. The elastica of the arterioles and small arteries was also found to bind the drug. Collagen and fibrocytes reacted in various ways. The pH, concentration, and time appear to be determining factors. Further clinical studies appear justified in selected cases.