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V C Maino

Publications and source records attributed to V C Maino.

44 records · Page 3Linked to original sources
PubMed1977

Mitogen activation of human chronic lymphatic leukemia cells. I. Synthesis and secretion of immunoglobulin.

The response of CLL (chronic lymphatic leukemia) lymphocytes to PHA, PWM, and Con A with respect to changes in surface markers and synthesis and secretion of immunoglobulin were examined. After PHA stimulation the percentage of cells bearing readily detectable surface immunoglobulin (SmIg) diminished rapidly whereas cells forming rosettes with sheep erythrocytes (E-rosettes) increased from less than 1% to 30 to 50%. The great majority of blast-transformed cells were E-rosette-positive cells with a small population of SmIg-positive blast cells also observed. Ig production in four of seven CLL lymphocyte populations was increased 2.5 to greater than 40-fold after 4 to 6 days of culture in the presence of PHA. In contrast, pokeweed mitogen did not affect Ig synthesis. Furthermore, the Ig secreted into the culture supernatant fluids from seven of eight CLL cases examined consisted almost entirely of free light chain molecules. In contrast, the cell lysates contained a significant proportion of intact Ig molecules. These results indicate that CLL cells can, under certain circumstances, be stimulated to synthesize and secrete increased amounts of Ig, but that there is a basic defect in the biosynthetic mechanism of these cells which result in the secretion of free light chains rather than intact immunoglobulin molecules.

B-Lymphocytes↗
PubMed1976

Bacteriophage resistance in Bacillus subtilis 168, W23, and interstrain transformants.

Strains of Bacillus subtilis 168 deficient in glucosylated teichoic acid vary in their resistance to bacteriophage infection. Although glucosylated teichoic acid is important for bacteriophage attachment, the results demonstrate that alternate receptor sites exist. Non-glucosylated cell wall mutants could be assigned to specific classes (gtaA, gtaB, gtaC) by their pattern of resistance to three closely related bacteriophages (phi25, phie, SP82). In addition to glucosylation, the type of teichoic acid was also important for bacteriophage attachment. B. subtilis strains 168 and W23 have different teichoic acids in their cell walls and have varied susceptibilities to bacteriophage infection. Transfer of bacteriophage resistance from strain W23 into a derivative of strain 168 was accomplished. The resistant bacteria obtained were imparied in their ability to adsorb bacteriophage and in their capacity to be transfected by bacteriophage deoxyribonucleic acid.

Adsorption↗
PubMed1975

Recognition at cell surfaces: phytohaemagglutinin-lymphocyte interaction.

Many aspects of cell behaviour are regulated by the interaction of extracellular ligands with specific receptors exposed on the cell surface. The receptors correspond to membrane proteins and expecially glycoproteins. A key event in regulation is the transmission across the surface membrane of the information resulting from receptor-ligand interaction. The activation of lymphocytes by Phaseolus vulgaris phytohaemagglutinin (PHA) provides a convenient experimental model for the study of the molecular basis of receptor-ligand interaction and the molecular consequences of interaction. The receptor mediating lymphocyte activation by PHA is probably a unique glycoprotein which is present to the extent of about 3 X 10(4) molecules/cell. The PHA-receptor complex solubilized in 1% sodium deoxycholate has a molecular size of about 3 X 10(5). The primary event in the activation process is probably an increase in the permeability of the surface membrane to Ca2+. This may be achieved by PHA cross-linking ('patching') the receptors to form a polar channel that permits an influx of Ca2+.

Animals↗
PubMed1975

Relationship between enhanced turnover of phosphatidylinositol and lymphocyte activation by mitogens.

1. Various lectins [phaseolus vulgaris phytohaemagglutinin, Glycine max (soy-bean) agglutinin, Triticum vulgaris (wheat-germ) agglutinin and Axinella polyploides agglutinin] and antibodies to pig Ig (immunoglobulin) that are found by pig lymphocytes were assessed in terms of their capacities to stimulate lymphocyte transformation and to enhance phosphatidylinositol turnover. Transformation was measured after 45h of culture by incorporation of [6-(3)H]thymidine into DNA, whereas phosphatidylinositol metabolism was assessed after 1h of cultuis and G. max agglutinins and rabbit antibodies to pig Ig) increased phosphatidylinositol turnover, but non-transforming agents (T. vulgaris and A. polyploides agglutinins and Fab fragments of rabbit antibodies to pig Ig) failed to induce any significant enhancement. Subsequent cross-linkage of the bound, non-transforming Fab fragments with a goat antiserum to rabbit Ig stimulated transformation and phosphatidylinositol turnover. 3. Each transforming agent gave characteristic optimal dose responses that were similar for both phosphatidylinositol turnover and transformation. 4. The results indicate that activation of T- and B-lymphocytes is accompanied by enhanced phosphatidylinositol turnover and that in the case of B-cells this enhancement depends on the cross-linkage of surface receptors. They are consistent with the proposal that turnover represents an essential early step in the transformation process.

Animals↗