Search

Human T-cell leukemia virus type 1 (HTLV-1) infection profoundly alters T-cell gene expression, and the dysregulated synthesis of cytokines could influence the course and pathologic consequences of infection. In the process of screening T-cell lines for T helper 1 (Th1) and Th2 cytokine mRNAs, we observed that interleukin-13 (IL-13) mRNA was highly expressed in HTLV-1-infected, IL-2-dependent T-cell lines. IL-9 and interferon gamma (IFN-gamma) mRNAs were also expressed at high levels in chronically infected cell lines. IL-5 mRNA was detected in 60% of the HTLV-1-infected cell lines, but mRNAs for IL-4, IL-10, IL-2, and IL-15 were either below detection limits or did not correlate with HTLV-1 infection. Transcriptional activation of the IL-13 promoter by the HTLV-1 Tax trans-regulatory protein was demonstrated in Jurkat T cells transiently transfected with an IL-13 promoter-reporter plasmid. The clinical relevance of these observations was demonstrated by immunofluorescent staining and flow cytometry of lymphocytes obtained from HTLV-1-infected patients. These studies revealed that IL-13 production was directly related to the level of Tax expression in the infected CD4+ T cells soon after in vitro culture. As IL-13 plays key roles in tumor immunosurveillance, asthma, and central nervous system inflammation, it may contribute to the pathophysiology of HTLV-1-associated diseases.

Patients with hairy cell leukemia (HCL) and chronic lymphocytic leukemia (CLL) were treated with recombinant interferon alpha A (rIFN-alpha A). The binding of iodinated recombinant interferon-alpha to baseline samples of peripheral blood mononuclear cells (PBMCs) from the leukemia patients was compared with clinical responsiveness to rIFN-alpha A. HCL patients (8/10) responded to rIFN-alpha A therapy, whereas none (0/10) of the CLL patients studied responded. The PBMCs from the eight responsive HCL patients bound approximately twice as much iodinated interferon as the PBMCs from nonresponsive CLL patients. This difference was due to more high-affinity receptors per cell with no difference in the affinity of the interferon-receptor interaction. However, because PBMCs from HCL patients were larger than PBMCs from CLL patients, the cell surface receptor density was similar. The leukemic cells from one of the two nonresponsive HCL patients bound iodinated interferon similarly to the cells from the responsive HCL patients, whereas the leukemic cells from the other nonresponsive HCL patient bound considerably less. The rapidity of response of the HCL patients did not correlate with the level of binding of iodinated interferon. Our results suggest that the absolute number of interferon receptors per cell may be only one of several important parameters in the response to rIFN-alpha A therapy, and that the responsiveness of a particular lymphoproliferative disease or a particular patient to rIFN-alpha A therapy cannot be predicted or explained solely by the degree of interaction between IFN and its cell surface receptor.

A human lung tumor-associated antigen has been identified by Ouchterlony analysis in 86% of lung tumor extracts of all histologic types. It was not detected by this method in extracts of normal adult or fetal lung, 12/13 other tumors, normal tissues or in normal serum. The antigen was purified from the extract of an undifferentiated small cell lung carcinoma by DEAE-cellulose. Sephadex G-200, and antibody affinity chromatography. The purified antigen exhibited size and charge heterogeneity, yet all isolated forms produced precipitin lines of identity with each other, as well as with an extract of an unrelated squamous cell carcinoma of the lung. The major form had a Mr of 150 000 by gel filtration and 81 700 by detergent gel electrophoresis. By radioimmunoassay, elevated levels of antigen were detected in 0/15 normal sera, 7/13 stage I and 12/15 stage III lung cancer sera. The urine of a different patient with a small cell lung carcinoma contained a related antigenic activity, but the major component was 30 000-50 000 daltons. The antigen has also been detected in extracts of a continuous cell line from a large cell carcinoma of the lung (ChaGo). The antigen is being evaluated for its usefulness as a lung tumor marker.

As a preliminary step in the identification and isolation of antibodies to human cancers, we have developed a sensitive and convenient assay for antibody binding to cellular antigens. The basis for the method is antibody binding to glutaraldehyde-fixed cells (AbGfC) and quantitation with radioiodinated staphylococcal protein A (SpA). Glutaraldehyde fixation of intact cells, which does not appear to effect the ability to form antigen-antibody complexes, provides a convenient and standard supply of target cells which may be stored at 4 degrees C and used in the assay over a period of several months. The amount of antibody specifically bound to the cells is quantitated by the addition of 125I-labeled SpA. The sensitivity of the method was compared with two complement-dependent cytotoxicity methods (trypan blue exclusion and 51Cr release assays) and tested with two antisera to human lung cancer and one antiserum to a membrane antigen of a murine lymphoma. These comparisons indicated much greater sensitivity when compared with the trypan blue exclusion assay and equivalent sensitivity with greater dose response characteristics when compared with the 51Cr release assay.

A human lung tumor-associated antigen (LTA) previously purified from a primary lung tumor has been identified in the sera of lung cancer patients. Frequencies of LTA elevations in lung cancer were: adenocarcinoma, 60%; squamous cell carcinoma, 42%; large cell carcinoma, 17%; and small cell carcinoma, 19%; normals, 2%; benign lung disease, 0%; and non-lung malignancies, 13%. The antigen was also shown to be produced by seven of the eight human lung tumor cell lines that were examined. A preliminary small-scale purification was attempted on an extract from one of these lines, ChaGo, which yielded a smaller and more basic form of LTA but which possessed similar, if not identical, antigenic activities as primary tumor LTA.