Biomedical subjects

C Abraham

Publications and source records attributed to C Abraham.

3 recordsLinked to original sources

PubMed1979

T-cell division and aging.

The age-dependent drop in mixed lymphocyte reactivity and responsiveness to concanavalin A of lymph node and spleen cells of C57Bl/6J female mice were studied. The relative decrease in mixed lymphocyte reactivity was shown to be the same whether mounted against H-2 or Mls incompatibile stimulator cells. The time of peak response in vitro as well as the sensitivity to stimulator cell concentration are not altered with age. Cell cycle studies demonstrate that those cells which respond in vitro to alloantigens or to concanavalin A do so with a cell cycle which does not change with the age of the lymphocyte donor. In addition, regardless of the age of the donor, those cells which divide in vitro demonstrate identical capacities to redivide. These experiments suggest that the decline in observed T-cell proliferation in mixed lymphocyte and mitogen reactivity of senescent mice is not to a decreased cell generation time or to a reduced capacity to divide and redivide but rather to a smaller population of reactive cells.

Aging↗

PubMed1978

Studies on the influence of the methanol extraction residue tubercle bacillus fraction on immunological responsiveness of mice. Effects on antibody formation to a soluble protein and a T-independent antigen, delayed hypersensitivity to sheep erythrocytes and numbers of antigen-reactive lymphoid cells.

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Animals↗

PubMed1977

Reduced in vitro response to concanavalin A and lipopolysaccharide in senescent mice: a function of reduced number of responding cells.

The proliferative capacity of spleen cells from C57BL/6J female mice of various ages (3-28 months) to the polyclonal mitogens concanavalin A (Con A) and lipopolysaccharide (LPS) was examined. It was found that both the T and B cell population of the spleen demonstrate an age-related decrease in their capacity to respond in vitro. Peak responses to both mitogens occurs at about 1 year of age. This age-related reduction in response is expressed in the degree of incorporation of [3H]thymidine into DNA, the total number of cells generated in vitro, the number of labeled cells per culture and the number of blast cells per culture. The day of peak response in vitro does not change with age. Studies of the cell cycle of cells responding to Con A and to LPS from 12 and 28-month-old mice demonstrate that the generation time of individual proliferating cells does not alter with age. Nor does it differ for the B cells responding to LPS or the T cells responding to Con A. These studies also demonstrate that the proliferating cells from senescent mice are equally capable of repeated cell divisions as are the cells from the 1-year-old adult mouse. It is concluded that the defect in senescent mice which leads to a reduced in vitro response to the polyclonal mitogens LPS and Con A is a reduction in the number of responding cells and not an alteration in the capacity of those cells which do respond to divide.

Aging↗