Inhibition by serum of encephalitogenic activity of myelin basic protein: nature of the serum factor responsible

Binding of soluble myelin basic protein to various conformational forms of alpha2-macroglobulin

Myelin basic protein is known to be released into the circulation following traumatic injuries or demyelination within the central nervous system, resulting in the generation of potentially immunogenic myelin basic protein material. In this investigation we have studied the binding of bovine and human myelin basic protein to human alpha2-macroglobulin, which was found to be the only major myelin basic protein-binding protein in human plasma. Myelin basic protein bound to all three conformational forms of alpha2-macroglobulin studied, i.e., native alpha2-macroglobulin, methylamine-treated alpha2-macroglobulin, and chymotrypsin-treated alpha2-macroglobulin. Zinc chloride (1 mM) or 1 mM iodoacetamide partly blocked the complex formation between myelin basic protein and alpha2-macroglobulin, while 1 mM magnesium chloride, 1 mM calcium chloride, or 1 mM EDTA had no effect on binding. Chymotrypsin and trypsin can degrade myelin basic protein to fragments which do not bind to alpha2-macroglobulin. However, when myelin basic protein was complexed with any of the conformational forms of alpha2-macroglobulin, no significant release of Na[125I]-labeled myelin basic protein occurred after proteinase treatment. The results suggest that binding of myelin basic protein to alpha2-macroglobulin may protect extracellular compartments in vivo from immunogenic myelin basic protein fragments and alpha2-macroglobulin may participate in the specific clearance of myelin basic protein from the circulation.

Influence of cerebroside and ganglioside on the encephalitogenic activity of myelin basic protein in guinea pigs

The effect of 2 central nervous system glycolipids (cerebroside and ganglioside) on the encephalitogenic activity of bovine myelin basic protein (MBP) was studied in guinea pigs. Mixing each of these glycolipids with MBP and injection of these mixtures in Freund's incomplete adjuvant (FIA) abrogated the resistance to encephalomyelitis upon challenge with MBP in Freund's complete adjuvant (FCA). Primary injection of these glycolipid-MBP mixtures in FCA diminished the clinical signs of experimental allergic encephalomyelitis (EAE) as compared to primary injection of MBP in FCA. Considering the amount of ganglioside needed to optimally induce these effects, this phenomenon seemed to be aspecific. However, with cerebroside, only minor quantities were sufficient, suggesting specific interaction with the basic protein. In several aspects, close correlation was found between cellular immune activity to MBP as measured by skin reactivity and the development of EAE.

Biologic markers and breast cancer: a multiparametric study--1. Increased serum protein levels

From early 1972 to the end of 1976, the profiles of several serum protein were used to monitor disease stage and prognosis of 207 patients with breast cancer. Six of these proteins, alpha 1-antitrypsin (alpha-AT), alpha 2-ceruloplasmin (Cp), beta 1-transferrin, IgA, C4, and C5, were significantly elevated in these cancer patients and were used as biologic markers in a multiparametric study. Among these breast cancer patients, 72% had at least two of these protein levels elevated, of which alpha-AT (55%), C5 (38%), and IgA (36%) levels were most commonly raised. The number of elevated proteins was parallel to disease progression as 61% (Group 1) and 74% (Group 2) of the patients with operable breast cancer and 90% of patients with metastatic disease showed an elevation of two or more of these nonspecific proteins. There was also a positive correlation between the number of elevated proteins and prognosis; of the 26 patients who died during the five-year follow-up, only four (15%) had no more than one protein level elevated, and 22 (85%) had two or more protein levels elevated. On the other hand, when considered as a group, patients with no or only one protein level elevated had a better prognosis than patients with two or more levels elevated (P less than 0.03). This multiparametric study tends to indicate that the high level of these serum proteins, reflecting an abnormal biochemical profile, provides valuable information that relates to the stage of the disease and patients' prognosis. Results also suggest that these proteins may aid in differentiating the group with high recurrent risks from that with a more favorable prognosis for a given clinical and pathologic stage, illustrating their importance as biologic markers in breast cancer.

Studies on the inactivation of encephalitogenic myelin basic protein by serum

This study confirms previous reports that myelin basic protein loses its encephalitogenic activity when incubated in normal serum at 37 degrees C. The mechanisms for this was studied. 125I-labelled human myelin basic protein was rapidly degraded by normal guinea pig serum to low molecular weight products as shown by polyacrylamide gel electrophoresis. An intermediate product of molecular weight about 6000 daltons was seen. Plasma had a much lower degradative activity than serum; the half life of myelin basic protein was 3.8 hours in plasma compared with 12 minutes in serum. Serum degraded myelin basic protein was no longer capable of suppressing experimental allergic encephalomyelitis in the guinea pig nor of eliciting delayed-type hypersensitivity in guinea pigs sensitized to myelin basic protein.

Evidence for suppressor cells in Lewis rats' experimental allergic encephalomyelitis

In this work we demonstrate a suppressive activity on the induction of experimental allergic encephalomyelitis (EAE) in Lewis rats, transferable to syngeneic animals, challenged with encephalitogenic mixture (myelin basic protein, complete Freud's adjuvant plus Bordetella pertussis organisms) 24 h later. This activity is probably effected by T cells and not by (an) inhibitory serum factor(s). The induction of this specific protection could be due to the penetration of the myelin basic protein antigen into the thymus where we first found suppressive cells. From the thymus, suppressor cells could then emigrate to spleen (on day 15) and to nondraining lymph nodes (on day 17). In the course of normal EAE in Lewis rats and especially at the time of self cure, this suppression is not demonstrated, but possible.

T cell necessity in the pathogenesis of experimental autoimmune encephalomyelitis in mice

Cellular transfer of experimental autoimmune encephalomyelitis (EAE) was effected in mice with lymph node and spleen cells from appropriately immunized donors. In contrast to lymphoid cells, immune serum did not transfer this autoimmune disease nor did serum have any facilitating or inhibitory effect on the capacity of lymphoid cells to transfer EAE. Transfer of EAE was effected in normal mice, lightly irradiated (350 rad) and lethally irradiated (850 rad) and bone marrow-protected mice, but not in mice which had been given 850 rad total-body irradiation. There was a striking augmentation of severity of transferred EAE in the lightly irradiated recipients, possibly attributable to selective radiosensitivity of suppressor T cells. Cell-mediated immunity but not circulating antibody to basic protein of myelin was demonstrated in recipients with transferred EAE. The immune lymphoid cells responsible for transfer of EAE were T lymphocytes. Thus transfer was successful after passage of sensitized cells through anti-immunoglobulin columns and was abrogated following treatment with anti-Thy-1 serum and complement. Neonatally thymectomized mice failed to develop either EAE, cell mediated immunity or humoral antibody against myelin basic protein (BPM). Inhibition of EAE and immune responsiveness was solely due to the removal of the source of thymus lymphocytes, because reconstitution of neonatally thymectomized mice with T lymphocytes completely restored these functions. It is concluded that T lymphocytes are required for the production and adoptive transfer of EAE, for the development of cell-mediated immunity to BPM and for the production of antibody to BPM.