Stimulation of granulocyte (PMN) superoxide (O2-) production by concanavalin-A (Con-A) can be monitored continuously in the spectrophotometer. Both the rate of activation and final activity of the O2--generating system is dependent on the concentration of Con-A. Alpha methylmannoside (alpha MM) can prevent Con-A, but not phorbol myristate acetate (PMA) or zymosan, induced O2- production. Alpha ...

This study was aimed to find a correlation between the extent of concanavalin A (Con A) binding to lymphocytes and the blastogenic effect of the lectin on these cells. 63Ni-labeled Con A was used in the lectin-binding experiments. Binding of Con A to a small fraction (approximately 3#{176}/o) of Con A binding sites in rat lymphocytes is required for the maximal stimulation of RNA synthesis. Bin...

Concanavalin A (Con A), a tetravalent lectin, was shown to impair 8 chick embryo fibroblast (8 d CEF) spreading on a laminin (LM) substrate but not on a fibronectin substrate (FN), suggesting that cell surface Con A binding proteins could be involved in 8 d CEF spreading on a LM substrate. The interaction of Con A-binding proteins with Con A is dependent upon the carbohydrate moieties of the is...

Human neutrophils stimulated by concanavalin A (Con A, 100 microng/ml) contained markedly enhanced numbers of microtubules and discharged peroxidase-negative (specific) but not peroxidase-position (azurophile) granules. Release of lysozyme from specific granules was dose and time dependent, could be inhibitied by alpha-methyl-D-mannoside, and enhanced by cytochalasin B. Many microtubules were a...

Previous studies (KALB, A. J., AND LEVITZKI, A. (1968) Biochem. J. 109, 669; SHOHAM, M., KALB, A. J., AND PECHT. I. (1973) Biochemistry 12, 1914) were interpreted as showing that transition metal and calcium ions must be bound to concanavalin A before this lectin can bind sugars. In contrast, we find that the addition of calcium ions fails to affect the following properties of manganese concana...

A 5-20% Ficoll velocity sedimentation gradient has been successfully applied to separate concanavalin A (Con A)-induced helper; and suppressor T cells. When titrated into a constant number of fresh normal spleen cells responding to sheep erythrocytes, cells from the top pool show stimulatory effects while those from the bottom pool show inhibitory activity. Both activities are found to be Con A...

T lymphocytes that are activated in the autologous mixed lymphocyte reaction (MLR) have suppressor activity. Concanavalin A (Con A) augments the suppressor activity generated in cultures containing both T and non-T lymphocytes and can induce suppressor activity in T-lymphocyte preparations that contain too few (10%) non-T cells to generate a significant autologous MLR. However, when such T-lymp...

By pretreatment with concanavalin A (Con A) both in vivo and in vitro genetically susceptible mice and their cultured macrophages have been converted to animals and cells which are phenotypically resistant to mouse hepatitus virus (MHV). Con A at 1.0 mg/mouse decreased the mortality from 100% to less than 40% by inducing a prominent inflammatory response, increasing the number of macrophages in...

The binding of I-labelled concanavalin A (I-Con A) to the cell surface has been studied in Ehrlich ascites tumour cells (EATC) and beef erythrocytes under various conditions. The binding of concanavalin A (Con A) to the cell surface was very specific and the available binding sites were saturated within a few minutes. The amount of I-Con A bound to EATC was 4-14 x io molecules/cell at 37 °C and...

Peptide ligands for the carbohydrate-binding protein concanavalin A (Con A) have been identified by screening a large, diverse peptide library expressed on the surface of filamentous phage. A dodecapeptide containing the consensus sequence Tyr-Pro-Tyr was found to bind Con A with an affinity (dissociation constant, Kd) of 46 microM, comparable to that of a known carbohydrate ligand, methyl alph...