Effect of multiple sclerosis alpha 2-macroglobulin on mitogen induction of lymphocyte proliferation

Native and transformed alpha2-macroglobulin in plasma from patients with multiple sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disease with unknown etiology. Various proteinases have been observed in increased levels in the central nervous system of patients with MS, which may contribute to the release of immunogenic myelin components. alpha2-Macroglobulin (alpha2M) inhibits a broad spectrum of proteinases sterically, undergoing major conformational changes induced by the proteinases themselves. Moreover, alpha2M acts as a carrier of several cytokines in the systemic circulation. By use of radial immunodiffusion, we determined the total alpha2M levels in plasma from 28 MS patients and 15 control subjects [14 patients with other neurologic diseases (OND) and one healthy individual]. No significant differences in total alpha2M concentration were observed between the MS patients and the control subjects. A comparison of the degree of alpha2M transformation in MS patients with different disease courses and controls was performed, using monoclonal antibodies (mAbs) specific for binding to native and transformed alpha2M, respectively. The fractions of transformed alpha2M were significantly increased in patients with secondary or primary progressive disease course compared with the controls. No significant differences were obtained using a native-specific mAb. At least a major proportion of alpha2M from the MS patients was able to change conformation from its native to its transformed state, as demonstrated by a shift in mAb reactivity, following methylamine treatment of the plasma samples. In conclusion, the results indicate that plasma alpha2M may be inactivated at a higher degree in patients with chronic progressive MS compared with patients with OND. This may influence the levels of proteinases and cytokines in the systemic circulation and may furthermore have diagnostic implications.

Aberrant forms of alpha(2)-macroglobulin purified from patients with multiple sclerosis

The biochemical properties of alpha(2)-macroglobulin were investigated in four patients with multiple sclerosis and compared to alpha(2)-macroglobulin from healthy controls. An impaired stability of alpha(2)-macroglobulin from the multiple sclerosis patients was demonstrated as a spontaneous conversion to an electrophoretic"fast" form of alpha(2)-macroglobulin upon purification and storage, with a concomitant decrease in functional capacity to inhibit proteinases. The ability to form complexes with proteinases was significantly reduced in alpha(2)-macroglobulin purified from the multiple sclerosis patients. The aberrant molecular arrangements of the protein were not due to proteinase cleavages in the bait regions of alpha(2)-macroglobulin, as demonstrated by gel electrophoresis and protein sequencing. The number of functional thiol esters, however, was reduced in alpha(2)-macroglobulin purified from the multiple sclerosis patients, an observation compatible with the impaired proteinase binding property. Furthermore, differences in isoelectric points were observed between alpha(2)-macroglobulin from the multiple sclerosis patients and alpha(2)-macroglobulin from healthy controls. The results suggest that aberrant forms of alpha(2)-macroglobulin may be present in patients with multiple sclerosis.

Effect of serum on lymphocyte blastogenesis. 2. Characterization of disease-induced immunosuppressive factors by chromatography and molecular weight determination

Numerous infectious and noninfectious diseases are associated with the appearance of suppressive serum lymphocyte immunoregulatory factors (SLIFs). The suppressive SLIFs in sera from clinically healthy dogs and from dogs with bacterial (staphylococcal, brucellar) or mycotic (blastomycotic) infections were further characterized by dialysis, fractionation by ultrafiltrations and HPLC (high performance liquid chromatography) sieving, by affinity chromatography on protein A-Sepharose columns, and by DEAE-cellulose ion exchange chromatography. Factors of various molecular weights and of various elution patterns from DEAE-cellulose and affinity chromatography columns were taking part in the suppressive action of the whole serum. The 'common' inhibitors present in all sera were in the molecular weight range of 28 to 35 Kd, whereas the disease-induced suppressive SLIFs were present in various molecular weight categories. 'Common' suppressor SLIFs and some SLIFs from dogs with staphylococcal infections were partially dialysable; suppressive SLIFs induced in dogs with generalized brucellosis and blastomycosis were not dialysable. Protein A bound suppressive SLIFs from two of three dogs with staphylococcal pyodermas. DEAE-cellulose chromatography gave variable elution patterns with different animal sera. It is concluded that various suppressive SLIFs contribute to the immunosuppressive effect of the whole serum and no disease-specific suppressive SLIF could be identified.