IgG from Cows with Parturient Paresis Changes the Thermodynamic Behaviour of Bovine Erythrocyte Acetylcholinesterase

Abstract

Summary Parturient paresis affects about 10% of all cows. The most common treatment is injection of various Ca‐salts and MgCl2 and about 80% recover after repeated injections. The effect of IgG on the Arrhenius plot of bovine erythrocyte AChE was studied. The plot was normal, i. e. biphasic (a broken line) in the presence of IgG from healthy cows. The highest concentration tested was 10 mg/ml. Before one injection of the Ca‐Mg solution 5 mg/ml IgG from sera of paretic cows (n=10) changed the Arrhenius plots to monophasic (linear). Thus, paretic cows have antibodies against AChE. After injection the change to linear plots was observed already with 1 mg/ml IgG. Apparently, the level of antibodies in serum affecting AChE increased about 5‐fold. This is considered to be due to dissociation of bound antibodies from various AChEs. All cows recovered after one injection and release of AChE antibodies might be important for the recovery. Incubation of blood from paretic cows (n = 3) with Ca‐salts and MgCl2 increased the amount of free AChE‐antibodies about twofold; the Arrhenius plots became linear at 2.5 mg/ml IgG compared with 5 mg/ml before the incubation. This should be due to release from AChEs on blood corpuscles as erythrocytes and lymphocytes. But the increase of antibodies after incubation of blood does not account for the whole increase following the treatment of paretic cows. AChE antibodies are probably also dissociated from other sites, such as neuromuscular junctions.

Origin and Significance of Acetylcholine and Choline in Plasma and Serum from Normal and Paretic Cows

“…Ca-infusions release antibodies (AXELSSON et al, 1990) and by experience give about 60--80%, recovery in bovine paresis. The nature of this antibody thus seems to be of crucial importance.…”

“…Adjusted for plasma concentration there is only a small inhibition (4-77,) by pure IgG on bovine erythrocyte and plasma AChE against a 90% safety margin in cholinergic transmission. The pure IgG must be derived from a thermaly dissociated immune complex as in the investigation by AXELSSON et al (1990).…”

“…One effect of the usually benificial Ca-therapy is the release of considerable amounts of IgG-antibodies into circulation (AXELSSON et al, 1990). The type of the investigated antibodies, like those against the nematode and for instance a protozoan AChE, will in turn give rise to anti-antibodies (OUAISSI et al, 1988) which like the original antigens can bind acetylcholine (ACh).…”

Cholinesterases and Unified Neurophysics

“…Largely regardless of varied clinical appearance and in the best 70 % of acute cases -hundreds of thousands of multifactor dependent violently spastic or deeply comatose ruminants have recovered within an hour by infusion of a cheap and relatively small dose of Ca-preparations. The electrolyte has been found to change the thermodynamic behaviour of AChE and furthermore release specific antibodies in test tubes (Axelsson et al, 1990), most probably by restoring protein folding in a deranged aqueous dipole momentum. Although paralytic conditions could be provoked by actively secreted nematode AChE in dairy cows, their ChE-activities in whole blood and plasma were not significantly changed (Axelsson and Luthman, 1983).…”