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Biomedical subjects

J Andersson

Publications and source records attributed to J Andersson.

At least 325 records · Page 18Linked to original sources
PubMed1977

Frequencies of mitogen-reactive B cells in the mouse. II. Frequencies of B cells producing antibodies which lyse sheep or horse erythrocytes, and trinitrophenylated or nitroiodophenylated sheep erythrocytes.

The B-cell mitogens LPS and lipoprotein stimulate 20-35 percent of all B cells in the spleen of 6- to 8-wk old C3H/Tif mice, as determined by limiting dilution analysis of precursors. Each reactive cell grows to a clone of IgM-secreting PFC, enumerated in a hemolytic plaque assay detecting all IgM secreting cells, regardless of v-region specificity. We have used these mitogens to reveal the total repertoire of Ig specificities produced by these mitogen-reactive B cells. We have determined in plaque assays with six different target erythrocytes the number of spleen cells limiting to one the number of mitogen-reactive B cells detected as specific IgM-secreting clones in each of these plaque assays. By this method, the absolute frequencies of precursor B cells with defined v-gene specificities could be calculated, for at least, one third of all B cells. The frequencies of specific IgM-plaque-forming B-cell clones within the total pool of mitogen-reactive B cells was 1 in 10 for NIP(12),-SRC, 1 in 50 for TNP(12)- SRC, 1 in 100 for NIP(1)-SRC, 1 in 160 for TNP(3)- SRC, 1 in 500 for HRC, and 1 in 1,000 for SRC. These frequencies were the same in the LPS- and in the lipoprotein-reactive B-cell population for TNP(30)- SRC and SRC.

Animals↗
PubMed1977

Clonal growth and maturation to immunoglobulin secretion in vitro of every growth-inducible B lymphocyte.

The frequency of normal murine B lymphocytes initiating growth in diluted suspension cultures in the presence of a B cell mitogen, such as lipopolysaccharide, can be increased approximately 10(4) fold by the addition of 2 X 10(6) normal thymus cells per ml. This increase in the frequency of growing cells by thymus cells can also be observed with X63-AG8 myeloma tumor cells secreting IgG1. Thus thymus cells may not contribute growth-stimulating factors, but may supply growth-supporting factors. Culture medium and plastic dishes can be conditioned by preincubation with thymus cells for a day after which the thymus cells may be omitted from further culture for maximal B cell growth. Irradiation of thymus cell abolishes their growth-enhancing properties. Thymus cells can be syngeneic and allogeneic with the growing B cells. The frequency of growing LPS-reactive, normal B cells in spleen of 6-8 week old C3H/Tif mice was determined by limiting dilution analysis to be one of three splenic B cells. With this limiting dilution analysis, it was also shown that the cloning efficiency of XB3-AG8 myeloma tumor cells in suspension culture in the presence of thymus cells is practically 100%. Analysis of the growth kinetics of single clones of LPS-reactive, normal B cells shown that these B cells divide every 18 hr. Within the first 126 hr of growth, every B cell in the clone divides, and every dividing B cell in this clone secretes sufficient immonoglobulin to form a hemolytic plaque. The conditions of in vitro suspension cultures of murine B lymphocytes are therefore perfect to the extent that every B cell capable of growth will grow as a single clone.

B-Lymphocytes↗
PubMed1975

Continuous growth of mitogen-reactive B lymphocytes.

B-cell mitogens induce continous growth of murine lymphocytes in suspension cultures. Continuous growth is observed only at low cell densitiess, below 10(6) cells/ml, in regularly renewed medium containing beta-mercaptoethanol and a growth-supporting fetal calf serum. Continuous growth of B lymphocytes in culture appears to be favored by conditions under which maturation of Ig-secreting plaque-forming cells does not occur. On the other hand, maturation is observed whenever stimulated B cells cease to divide. This maturation leads to IgM secretion followed by secretion of IgG- or IgD-like molecules. Neither continuous growth of B cells nor the 'switch' to secretion of IgG- or IgD-like molecules requires the presence of T cells.

Animals↗
PubMed1975

Brain uptake of lactate, antipyrine, water and ethanol.

Brain uptake of antipyrine, water and ethanol was studied in rats under normo-, hypo- and hypercapnic conditions. Brain uptake of D- and L-lactate was studied in normal rats. The uptake was determined with the Oldendorf method, using single common carotid arterial injections of a mixture of -14C-labeled test substance and tritiated reference substance. The results demonstrate that L-lactate is taken up by the brain in significant amounts. The results also demonstrate marked differences in the uptakes of antipyrine, water and ethanol. The brain uptake of antipyrine is lower, the brain uptake of ethanol higher, than of water. The brain uptake of all 3 substances was shown not to be affected by changes in cerebral blood flow, although a decrease of brain uptake of antipyrine relative to ethanol was observed during hypo- and hypercapnia.

Animals↗
PubMed1974

IgM-producing tumors in the BALB-c mouse: a model for B-cell maturation.

Five adjuvant induced BALB/c tumors producing IgM-McPc 1748, W 3469, TEPC 183, McPc 774, and Y 5781-were characterized morphologically by electron microscopy, analysis of the distribution of surface-bound and intracytoplasmic IgM using immunofluorescence, and by biochemical study of IgM synthesis, turnover, and secretion. The cells of different tumors appear to represent different stages in B-cell maturation when compared to normal, lipopolysaccharide-stimulated B cells. Thus, McPc 1748 tumor cells resemble 10-25-h stimulated normal B cells, 3469 cells resemble 20-35-h stimulated B cells, TEPC 183 cells resemble 45-65-h stimulated B cells, Y 5781 cells resemble 80-110-h stimulated B cells, and McPc 774 cells resemble 100-130-h stimulated B cells.

Animals↗