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Biomedical subjects

A F Wells

Publications and source records attributed to A F Wells.

23 records · Page 2Linked to original sources
PubMed1966

Rapid fluorescein and protein assay method for fluorescent-antibody conjugates.

A method is presented for the rapid determination of the fluorescein content, protein content, and fluorescein-to-protein ratio for immune globulin conjugates with fluorescein isothiocyanate as the fluor. This method is based on the absorbance of the fluorescent antibody at those wavelengths primarily associated with the fluorescein and gamma-globulin fractions, and permits these materials to be determined by a single nondestructive analytical procedure. A small sample of the fluorescent antibody, in many cases 0.1 ml or less, is adequate for the above determinations. A nomograph is presented which allows simultaneous determination of the materials from the observed absorbance at the two wavelengths. The method is sufficiently accurate for most applications of the fluorescent-antibody techniques. Although this procedure has been developed primarily for fluorescent-antibody conjugates prepared from rabbit gamma-globulin, it can be used directly for antibodies prepared from other animals provided the gamma-globulin is relatively free from albumin.

Animals↗
PubMedDate not supplied

Expression of an interferon-gamma-like substance in normal and transplanted rat heart tissue.

The presence of interferon-gamma-like molecules has been reported not only in lymphocytes, but also in certain nerve cells and in normal skeletal muscle. We have studied the reactivity of the anti-interferon-gamma monoclonal antibody DB1 with frozen sections of normal and transplanted rat hearts. Cardiac grafts from PVG donor rats were transplanted to syngeneic PVG recipients or allogeneic Wistar/Kyoto recipient rats with the use of an accessory cervical heart transplantation technique. The allogeneic heart transplants were harvested 4 days and the syngeneic grafts 4 weeks after transplantation. In normal hearts there was a weak but distinct reactivity with the anti-interferon-gamma antibody in most muscle cells. In addition, some lymphocytes and the Purkinje fibers were positive. Hearts transplanted over an allogeneic barrier revealed that staining for interferon-gamma on muscle cells was substantially increased whereas no or only a moderate increase in the anti-interferon-gamma staining was seen in hearts transplanted to syngeneic recipients. These data indicate that interferon-gamma present in rat myocyte may be involved in the pathophysiology of graft rejection and also suggest that interferon-gamma may be of importance for the function of normal rat heart muscle cells.

Animals↗
PubMedDate not supplied

Expression of interleukin-2 receptor alpha (IL-2R alpha) mRNA and protein in advanced epithelial ovarian cancer.

Advanced epithelial ovarian cancer has recently been identified by us to be associated with elevated serum and ascitic levels of the soluble Interleukin-2 receptor alpha (sIL-2R alpha). To determine the cellular source of sIL-2R alpha, the expression of IL-2R alpha was assessed at the mRNA and protein level in peripheral blood mononuclear cells (PBMC), in ovarian cancer ascitic cell infiltrates and in primary and metastatic epithelial ovarian cancer lesions by immunochemistry, by flow cytometric analysis and by in situ hybridization (ISH). Normal PBMC and the PBMC from ovarian cancer patients had a low or undetectable level of IL-2R alpha mRNA and of IL-2R alpha cell-surface protein expression. Flow cytometric analysis of the heterogeneous ascitic infiltrates revealed few cells positively expressing cell-surface IL-2R alpha. By immunocytochemistry, 1-2% of leukocytes in the ascitic infiltrates were IL-2R alpha+. Cytologically these IL-2R alpha+ cells were lymphocytes. Frozen sections of primary and metastatic ovarian cancer lesions showed sparse lymphocytic infiltration and very small numbers of these tumour infiltrating lymphocytes (TIL) were IL-2R alpha+. In situ hybridization demonstrated that although less than 2% of leukocytes in the ascitic infiltrate had detectable levels of IL-2R alpha mRNA, there was a wide range in the level of mRNA expression in these positive cells. The cells expressing IL-2R alpha mRNA had the cytologic characteristics of lymphocytes. Similarly, in the frozen sections of the solid tumours, there was a range in the level of IL-2R alpha mRNA expression in the few TIL that expressed IL-2R alpha. Importantly, ovarian cancer cells and mesothelial cells did not express IL-2R alpha mRNA or IL-2R alpha protein. Our observations lead us to conclude that lymphocytes are the main, if not the only, source of sIL-2R alpha in ovarian cancer patients. Although cells expressing IL-2R alpha were relatively few in number, as the source of the high levels of sIL-2R alpha, they may contribute to the immunosuppression of ascitic lymphocytes in advanced epithelial ovarian cancer.

Ascites↗