Immunoglobulins in disc electrophoresis

Carrier-free zone electrophoresis, displacement electrophoresis and isoelectric focusing in a high-performance electrophoresis apparatus

A characteristic feature of high-performance electrophoresis (HPE), the electrophoretic counterpart of high-performance liquid chromatography (HPLC), is that the separation chamber is a thin-walled, narrow-bore (0.05-0.3 mm) glass or fused-silica capillary tube for rapid dissipation of the Joule heat in order to minimize thermal zone deformation even at high field strengths. This paper is centered around the usefulness of HPE for separation in a carrier-free medium (i.e., in buffer alone) and deals with both zone electrophoresis, isoelectric focusing and displacement electrophoresis. Examples are given of analytical and micropreparative separations of inorganic and organic ions, proteins, viruses and bacteria. The run times are 5-30 min. Discontinuous buffer systems have up to now been used exclusively for the separation of proteins by electrophoresis in polyacrylamide gels ("disc electrophoresis"). However, the Ornstein and Davis discontinuous buffer system has been modified to adapt it to carrier-free zone electrophoresis in order to achieve automatic sharpening of the starting zone. Very high resolution of serum proteins was obtained when they were subjected to free high-performance disc electrophoresis in such a modified buffer system. To show that the HPE apparatus permits electrophoresis also in a gel medium, a polyacrylamide electrophoresis in SDS is presented. This experiment illustrates the difference between electropherograms obtained in free solution and in a molecular-sieving medium. Detection can be performed both on- and off-tube. The latter technique permits the rapid identification of the solutes by photodiode array spectrophotometry and the collection of fractions for further studies. The former detection method is simpler but mainly useful for analytical purposes. Non-UV-absorbing ions can be monitored with the aid of an on-tube UV detector if the run is performed in a UV-absorbing buffer.

Alpha-2-macroglobulin, albumin, and chymotrypsin inhibitory capacity in cerebrospinal fluid as indices of blood-cerebrospinal fluid barrier

Concentration of alpha-2-macroglobulin, albumin, and chymotrypsin inhibitory capacity representing mainly alpha-1-proteinase inhibitor were estimated in cerebrospinal fluid in disorders of the central nervous system. While chymotrypsin inhibitory capacity was elevated in all cases with derangement of the blood-cerebrospinal fluid barrier, in 30% of the cases alpha-2-macroglobulin levels were in the normal range. The difference can be attributed to the much larger size of the latter. Better correlation between albumin concentration and chymotrypsin inhibitory capacity (r = 0.84) than between albumin and alpha-2-macroglobulin (r = 0.62) supports the view that the rate of entry of proteins from blood into cerebrospinal fluid is inversely related to their size.

Polyacrylamide-gel disc electrophoresis of native cerebrospinal fluid proteins with special reference to immunoglobulins and some clinical applications

Polyacrylamide-gel disc electrophoresis has been applied to the fractionation of CSF samples obtained from 2m control subjects (range of age 16 to 77 yr, mean 41.0 yr) and from 157 patients with various neurological diseases, with the purpose of evaluating the diagnostic significance of separated protein bands. It was found that the immunoglobulins, with some exceptions, were fractionated in the G-zone which was defined as an area between the origin and 0.57 in terms of relative migration based on transferrin (RT). Fourty-four percent of the whole Bence Jones protein bands which were examined were detected in the area of RT 0.70-0.90. The normal values of CSF protein fractions were (means+/-SD):Pre-alb-zone, 10.97+/-2.31%; Alb-zone, 40.74+/-5.72%; A1-zone, 5.25+/-0.72%; A2-zone, 8.23+/-1.24%; B1-zone, 10.82+/-2.18%. B2-zone, 7.94+/-1.93%; G-zone, 16.05+/-2.49%. The following significant results were obtained: (1) When the total protein concentration (TP) of CSF is increased: the percentage of the Pre-alb-zone is lowered and that of the A1- and G-zones is increased in diseases such as neurosyphilis, infectious meningitis, brain tumour, multiple sclerosis, intervertebral disc protrusion and cerebral infarction. The A2-zone was diminished in cerebral infarction, and a similar change was seen in brain tumour with in addition a decrease of the B2-zone; (2) When the TP was normal: the percentage of the G-zone was increased in multiple sclerosis, brain tumour and intervertebral disc protrusion. In the latter 2 disorders the A1-zone also increased. This fraction also increased in the cases of cerebral infarction, whose mean age was, however, much higher than that of the control subjects.