Paradoxical expression of adenosine deaminase in T cells cultured from a patient with adenosine deaminase deficiency and combine immunodeficiency.

T lymphocytes cultured from a patient (T.D.) with adenosine deaminase (ADA) deficiency expressed ADA activity in the normal range, inconsistent with her severe immunodeficiency, metabolic abnormalities, and with the absence of ADA activity in her B lymphocytes and other nucleated hematopoietic cells. ADA from T.D. T cells had normal Km, heat stability, and sensitivity to ADA inhibitors. Examination of HLA phenotype and polymorphic DNA loci indicated that T.D. was neither chimeric nor a genetic mosaic. Amplified and subcloned ADA cDNA from ADA+ T.D. T cells was shown by allele-specific oligonucleotide hybridization to possess the same mutations (Arg101----Trp, Arg211----His) previously found in the ADA-T.D. B cell line GM 2606 (Akeson, A. L., D. A. Wiginton, M. R. Dusing, J. C. States, and J. J. Hutton. 1988. J. Biol. Chem. 263:16291-16296). Our findings suggest that one of these mutant alleles can be expressed selectively in IL-2-dependent T cells as stable, active enzyme. Cultured T cells from other patients with the Arg211----His mutation did not express significant ADA activity, while some B cell lines from a patient with an Arg101----Gln mutation have been found to express normal ADA activity. We speculate that Arg101 may be at a site that determines degradation of ADA by a protease that is under negative control by IL-2 in T cells, and is variably expressed in B cells. Il-2 might increase ADA expression in T cells of patients who possess mutations of Arg101.

Placental-like alkaline phosphatase in malignant and benign ovarian tumors.

Alkaline phosphatase (ALP) components in extracts of seven malignant and eleven benign ovarian tumors were characterized using the criteria of electrophoretic mobility before and after neuraminidase treatment, heat stability, L-phenylalanine inhibition and reactivity against antiplacental ALP antiserum. Seven of the eighteen tumors had ALP components which most closely resembled the ALP isoenzyme normally found in placenta and were clearly distinguished from all other tissue ALPs. The proportion of tumors with the placental-like ALP in the malignant group (five out of seven) was significantly greater than the proportion in the benign group (two out of eleven). The fraction (78%) of the malignant tumors with the isozyme represents a larger percentage than has previously been found by examination of cancer patients' sera. The electrophoretic mobilities of the placental-like ALPs in the tumors were in no case identical to the mobilities of any of the six common placental ALP phenotypes. The tumor ALPs may thus be determined by rare variant alleles at the ALP locus, or alternatively, the enzyme molecules may have been subject to structural modification. At least two of these tumors contained an electrophoretically slow. heat-stable, leucine-sensitive ALP, which may correspond to what has been termed the D-variant of placental ALP found in some other tumors.

Heterogeneity of alkaline phosphatases in different HeLa lines.

Alkaline phosphatase (ALP) components in 8 cell lines of HeLa were examined. Line to line heterogeneity in ALP expression was observed using the criteria of electrophoretic mobility before and after neuraminidase treatment, heat stability, L-phenylanine inhibition, and reactivity against antiplacental ALP antiserum. Six lines contained a placentallike ALP isozyme and varying amounts of a liverlike ALP isozyme. One line contained a liverlike ALP isozyme only. One line contained a new ALP form which was clearly distinguished from the placental, liver, bone, and intestinal ALPs. Thus, derepression of the placental ALP structural locus appeared to have occurred in 6 of the 8 lines. However, where expressed, the placentallike ALP varied electrophoretically from line to line, and in only one case was the mobility identical to that of a common placental ALP phenotype. This phenotypic heterogeneity of the ""derepressed'' placentallike ALP contrasts markedly with the phenotypic stability of other enzymes expressed in HeLa cells.

Electrophoresis of human l-glutamate dehydrogenase: tissue distribution and preliminary population survey.

A method for the starch gel electrophoresis of human L-glutamate dehydrogenase (GLUD) is described, as is the tissue distribution of GLUD detected by this method. Extracts of livers from 200 Whites were analyzed without demonstration of an electrophoretic variant. The molecular size was estimated to be 330,000 and the isoelectric point pH 4.83.