Membrane Immunology and Permeability Functions

Goat antisera against (Na+ + K+)-ATPase and its isolated subunits and against (K+ + H+)-ATPase have been prepared in order to test for immune cross-reactivity between the two enzymes, whose catalytic subunits show great chemical similarity. None of the (Na+ + K+)-ATPase antisera cross-reacted with (K+ + H+)-ATPase or inhibited its enzyme activity. The same was true for the (K+ + H+)-ATPase antiserum with regard to (Na+ + K+)-ATPase and its subunits and its enzyme activity. So notwithstanding the chemical similarity of their subunits, there is no immunological cross-reactivity between these two plasma membrane ATPases.

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The influence of electrochemical gradients of Na+ and K+ upon the membrane binding and pore forming activity of the terminal complement proteins

Sims

Wiedmer

1984

J. Membrain Biol.

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The hemolytic activity of the terminal complement proteins (C5b-9) towards erythrocytes containing high potassium concentration has been reported to be dramatically increased when extracellular Na+ is substituted isotonically by K+ (Dalmasso, A.P., et al., 1975, J. Immunol. 115:63-68). This phenomenon was now further investigated using resealed human erythrocyte ghosts (ghosts), which can be maintained at a nonlytic osmotic steady state subsequent to C5b-9 binding: (1) The functional state of C5b-9-treated ghosts was studied from their ability to retain trapped [14C]-sucrose or [3H]-inulin when suspended either in the presence of Na+ or K+. A dramatic increase in the permeability of the ghost membrane to both nonelectrolytes - in the absence of significant hemoglobin release - was observed for C5b-9 assembly in the presence of external K+. (2) The physical binding of the individual 125I-labeled terminal complement proteins to ghost membranes was directly measured as a function of intra- and extracellular K+ and Na+. The uptake of 125I-C7, 125I-C8, and 125I-C9 into membrane C5b-9 was unaltered by substitution of Na+ by K+. (3) The binding of the terminal complement proteins to ghosts subjected to a transient membrane potential generated by the K+-ionophore valinomycin (in the presence of K+ concentration gradients) was measured. No significant change in membrane binding of any of the C5b-9 proteins was detected under the influence of both depolarizing and hyperpolarizing membrane potentials.(ABSTRACT TRUNCATED AT 250 WORDS)

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Membrane Immunology and Permeability Functions

Cited by 5 publications

References 121 publications

Active and Passive Cation Transport and Its Association with Membrane Antigens in Sheep Erythrocytes

Active and Passive Cation Transport and Its Association with Membrane Antigens in Sheep Erythrocytes

Lack of immunological cross reactivity between the transport enzymes (Na+ + K+)-ATPase and (K+ + H+)-ATPase

The influence of electrochemical gradients of Na+ and K+ upon the membrane binding and pore forming activity of the terminal complement proteins

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