Glia cell stimulating factor (GSF): a new lymphokine. Part 2. Cellular sources and partial purification of human GSF.

Glia cell proliferation is characteristic of many inflammatory and degenerative processes in the brain, however the mechanisms underlying this response are poorly understood. We described a glia cell stimulating factor (GSF), produced by murine spleen cells, which activates DNA- and RNA synthesis of cultured glia cells. In the present series of experiments, we examined the ability of Concanavalin A (ConA)-stimulated human peripheral blood mononuclear leukocytes (PBM) and two continuous cell lines derived from human lymphocytes to spontaneously release of GSF in culture. The studies presented herein demonstrate that (1) ConA-stimulated PBM of healthy subjects produced GSF, (2) GSF is produced by T lymphocytes in collaboration with monocyte-macrophages, (3) both the human T cell line (MOLT-4F) and a B cell line (RPMI 1788) spontaneously secrete GSF, (4) GSF was found to have a molecular weight of 30,000 and less than 10,000 daltons, (5) macrophage (MIF)- and leukocyte (LIF) migration-inhibiting factor activities, as well as mitogenic factor (MF)- and lymphocyte-activation factor (LAF) activities could be separated from the GSF activity by gel filtration on Biogel P-100. These findings provide further evidence for the existence of GSF as a new lymphokine, distinct from LIF, MIF, MF and LAF.

Induction of immunological tolerance to the penicilloyl antigenic determinant. II. Evaluation of stable and unstable penicilloyl dextrans.

A specific tolerant state to the major antigenic determinant of penicillin allergy, the penicilloyl group, was induced in C3H mice primarily immunized with penicilloylated bovine gamma globulin in complete Freund's adjuvant. Tolerance was obtained by intraperitoneal administration of either of two penicilloyl-bearing dextrans of molecular weight 2 X 10(6). One conjugate contained penicilloyl groups stably bound via a 1,6-diaminohexane spacer, the other bore the penicilloyl groups directly bound to the hydroxyl groups of the carrier. These directly bound penicilloyl groups undergo hydrolytic cleavage within 3 days under physiological conditions in neutral aqueous solution. Model experiments showed that the rapid cleavage into carrier and haptenic derivatives also applies to penicilloylated dextran in receptor-bound and particulate form, as may be expected from the highly hydrophilic character of the conjugate. The stable conjugate at 1 mg and the cleavable conjugate at 4 mg doses induced comparable tolerance lasting for at least 8-12 weeks.

Induction of immunological tolerance to the penicilloyl antigenic determinant. III. Suppression of benzylpenicilloyl-specific IgE antibody formation by cleavable penicilloylated dextran.

The suppressive effect of cleavable penicilloylated dextran (BPO-DEX), whose directly bound penicilloyl groups undergo hydrolytic cleavage within 3 days under physiological conditions, on murine IgE antibody formation against the benzylpenicilloyl (BPO) determinant was investigated in BALB/c and C3H mice. Intraperitoneal administration of BPO-DEX during either primary or secondary IgE responses to BPO ascaris produced a reversible suppression of BPO-specific IgE, while not affecting carrier-specific IgE antibody formation. Suppression of longer duration, at least 10 weeks, was achieved, however, by repeated administrations of BPO-DEX. BPO-DEX itself did not generate detectable BPO-specific IgE antibodies. These results suggest that BPO-DEX might be one of the promising tolerogens in the prevention of penicillin allergy.

Measurement of antilymphokine serum activities by the electrophoretic mobility test.

Purified human lymphocytes from peripheral blood were stimulated by Con A and the concentrated supernatants were used to induce antibodies in rabbits. These antilymphokine immune sera (ALKS) were able to inhibit the electrophoretic mobility of indicator cells, which was performed using supernatants of lymphocytes stimulated by Con A or PPD and tanned sheep red blood cells as indicator particles. If the method is standardized it is possible to compare several ALKS from different origin even in different models.

Induction of immunological tolerance to the penicilloyl antigenic determinant. I. Evaluation of penicilloylated amino acid polymers and copolymers in mice.

Antibody responses to the penicilloyl (BPO) group, the major antigenic determinant of penicillin allergy induced in C3H mice by penicilloylated bovine gamma globulin in complete Freund's adjuvant, were reduced or abolished by various amino acid polymers and copolymers of different composition and size carrying BPO groups. Tolerogenic treatment was effective before or after primary immunization and also during anamnestic responses. The unresponsive state was of long duration and persisted even after several booster injections when efficient tolerogens were used. Among the most promising tolerogens are fully penicilloylated oligolysines with a molecular weight below 10 000.