Separation of immunomodulatory effects of mannan from Candida albicans into stimulatory and suppressive components.

Mannan extracted from Candida albicans was studied for its immunomodulatory activity on in vivo antibody responses to type III pneumococcal polysaccharide (SSS-III), a helper-T-cell-independent antigen, and to sheep erythrocytes (SRBC), a helper-T-cell-dependent antigen. In some studies, the antibody response to SSS-III was converted to a helper-T-cell-dependent response by attaching it to a carrier (horse erythrocytes, HRBC); this complex then was used to immunize mice primed with a subimmunogenic dose of HRBC. Mannan enhanced the antibody response to both SSS-III and SRBC when administered at the same time or 1 or 2 days after immunogen. However, when both mannan and SSS-III were coated onto HRBC for immunization, either enhancement or suppression was noted; the effect depended upon the amount of mannan used. Larger amounts stimulated, whereas smaller amounts suppressed, the antibody response to SSS-III. The enhancing and suppressive components of mannan could be separated by molecular size or charge by chromatography on Sepharose 4B or on DEAE-Sephadex A-50 columns, indicating that mannan extracts contain individual components having opposing immunomodulatory properties. These components can be separated on the basis of molecular size and charge.

Genes on different chromosomes influence the antibody response to bacterial antigens.

B6.C congenic strains of mice, possessing histocompatibility (H) alleles from high responding BALB/cBy (C) mice on the genetic background of low responding C57BL/6By (B6) mice, were assayed for their ability to make an antibody response to Type III pneumococcal polysaccharide (SSS-III) and the alpha(1----3) epitope of bacterial (Leuconostoc) dextran B-1355. The results affirmed that the antibody response to SSS-III is multigenic and that genes making a positive contribution to responsiveness are located on different chromosomes, i.e., chromosomes 1, 3, 4, 5, and 9. At least one other gene also influences responsiveness to SSS-III; it is linked to the H-17 locus, which has not yet been assigned to a specific chromosome. Genes on chromosomes 1, 4, and 5 influence the magnitude of the antibody response to dextran B-1355. Some of these genes may be antigen-specific in their mode of action; however, others may not since they appear to exert a positive influence on the antibody response to both SSS-III and dextran B-1355.

Influence of multiple genes on the magnitude of the antibody response to bacterial polysaccharide antigens.

Studies conducted with F1 and F2 progeny of crosses between strains of inbred mice that differ greatly in their capacity to make an antibody response to type III pneumococcal polysaccharide, dextran B-1355, and lipopolysaccharide from Escherichia coli 0113 have shown that multiple genes influence the magnitude of the antibody response to these antigens. Other studies with hybrids derived from crosses between C3H/HeJ, CBA/N, and RIIIS/J mice have indicated that the genetic defects characteristic of these strains of mice are dissimilar and unlinked and that autosomal, as well as X-linked, genes control serum immunoglobulin M in unimmunized mice.

Characteristics of amplifier T cells involved in the antibody response to the capsular polysaccharide of type III Streptococcus pneumoniae.

Amplifier T cell activity can be transferred by spleen cells harvested 72 hr after priming with type III pneumococcal polysaccharide (SSS-III) and can be abolished by treating the transferred cells with monoclonal anti-Lyt-1, or anti-Thy-1 antibodies in the presence of complement; thus, amplifier cells represent a distinct subpopulation of T cells. Amplifier T cells were found to be sensitive to irradiation but not to treatment with cyclophosphamide. When amplifier cells were transferred to athymic nude (nu/nu) mice, the enhancement obtained was much greater than that produced in thymus-bearing (nu/+) mice; this is presumably due to the lack of suppressor T cell activity in nu/nu mice that enables amplifier T cell activity to be expressed more fully. Amplifier T cells also were found to be present in peripheral blood; these amplifier T cells were Lyt-2- in phenotype. Although the induction and activation of amplifier T cells appear to be antigen-specific, the product made by amplifier T cells may not be antigen specific in its mode of action. Because amplifier T cells can be induced and activated by exposure to immune B cells, specificity is presumably due in whole or in part to the ability of amplifier T cells to recognize the idiotypic determinants of B cell-associated antibody specific for SSS-III.

Lectin-induced modulation of the antibody response to type III pneumococcal polysaccharide.

Several lectins were tested for their capacity to alter the antibody response to type III pneumococcal polysaccharide (SSS-III). The antibody response was enhanced by concanavalin A (Con A), phytohemagglutinin (PHA), as well as lectins from Phytolacca americana (Pa-2), Pisum sativum (PSA), and Lens culinaris (LCH), when these lectins were given 2 days after immunization with SSS-III; however, suppression was obtained when Con A and Pa-2 were given at the time of immunization. By contrast the lectins from Vicia villosa (VVL) and Bauhinia purpurea (BPA) did not alter the antibody response. Since the lectins PSA and LCH bind to the same monosaccharide as Con A, whereas the other lectins bind to different monosaccharides, these findings indicate that there is no relationship between nominal monosaccharide specificity and the capacity to modulate the antibody response. Substantial increases in the magnitude of the IgG1 antibody response was noted after the administration of Con A whereas profound enhancement of IgG2a antibody response was noted after PHA was given.

Activation of antigen-specific suppressor T cells by B cells from mice immunized with type III pneumococcal polysaccharide.

The transfer of B lymphocytes from mice immunized with type III pneumococcal polysaccharide (SSS-III) results in antigen-specific suppression of the antibody response of recipients immunized with SSS-III. Such suppression shares many features associated with low-dose paralysis, a phenomenon mediated by suppressor T cells; it reaches maximal levels 3 d after the transfer of viable or irradiated immune B cells and can be eliminated by the depletion of SSS-III-binding cells from spleen cell suspensions before transfer. In a two-step cell transfer experiment, purified T lymphocytes, isolated from recipients previously given immune B cells, caused suppression upon transfer to other mice immunized with SSS-III. Also, B-cell-induced suppression could be abrogated in a competitive manner by the infusion of amplifier T lymphocytes, as was previously demonstrated in the case of low-dose paralysis. These findings suggest that B cell surface components, presumably the idiotypic determinants of cell-associated antibody specific for SSS-III, are instrumental in activating suppressor T cells involved in regulating the magnitude of the antibody response to SSS-III.

Cyclic expression of low-dose paralysis.

Prior treatment (priming) with a single injection of a subimmunogenic dose of Type III pneumococcal polysaccharide results in an antigen-specific T-cell-dependent form of unresponsiveness (low-dose paralysis) mediated by suppressor T cells. Although such unresponsiveness persists for several months after priming, it is expressed in a cyclic manner with a periodicity of about 3 days. This cyclic pattern is accompanied by concurrent periods of Velban sensitivity that also are cyclic. This suggests that the maintenance of low-dose paralysis in part requires some degree of cell proliferation which proceeds in an ordered manner in response to a "signal" generated after priming with antigen.

Cell surface antigens and other characteristics of T cells regulating the antibody response to type III pneumococcal polysaccharide.

The administration of a subimmunogenic dose of type III pneumococcal polysaccharide (SSS-III) produces an antigen-specific T cell-dependent phenomenon termed low-dose paralysis (immunologic unresponsiveness). This form of unresponsiveness can be transferred by spleen cells obtained 5 to 24 hr after priming, and the suppressive activity of the transferred cells is abolished by prior treatment with monoclonal anti-Lyt-2 and anti-I-J antibody in the presence of complement, indicating that suppression is mediated by a distinct subset of T cells (suppressor T cells). If primed spleen cells are transferred 24 to 72 hr after immunization with SSS-III, however, the resulting antibody response of immunized recipients is enhanced. Greater enhancement is noted when transferred cells, pretreated with monoclonal anti-Lyt-2 antibody plus complement to remove suppressor T cells, are used; such enhancement is attributed to amplifier T cells. These findings indicate suppressor T cells regulate the antibody response to SSS-III by influencing the expansion of SSS-III-specific clones of B cells as well as the expression of amplifier T cell activity; the latter causes B cells to proliferate further in response to SSS-III.

Direct evidence for the involvement of T suppressor cells in the expression of low-dose paralysis to type III pneumococcal polysaccharide.

Prior treatment (priming) with a subimmunogenic dose of type III pneumococcal polysaccharide results in the development of an antigen-specific state of unresponsiveness termed low-dose paralysis. Such unresponsiveness can be transferred by spleen cells obtained from mice within 5 to 24 hr after priming; the suppressive activity of transferred cells is abolished by treatment with monoclonal anti-Thy-1.2 antibody and complement. These findings show clearly that low-dose paralysis is mediated by T suppressor cells.

Regulation of the antibody response to pneumococcal polysaccharide by thymus-derived cells.

The dose-response relationships in mice immunized with capsular polysaccharide of type 3 Streptococcus pneumoniae (SSS-III) show a distinctive pattern characterized by a single optimal dose for immunization within a relatively narrow range of immunizing doses. Most of the antibody produced is of the IgM class, and the kinetics for the development of both the cellular and serum antibody response to this antigen are parallel up to the peak of the immune response. Although thymus-derived (T) cells are not needed to initiate an antibody response to SSS-III, the magnitude of the antibody response is influenced greatly by the activities of two types of T cells with opposing functions; such regulatory T cells have been termed suppressor and amplifier T cells. The mode of action of suppressor and amplifier T cells as well as the manner in which they might interact during the antibody response to SSS-III are discussed.

Use of the periodate oxidation coupling method for the detection of antibody and antibody-producing cells specific for staphylococcal lipoteichoic acid.

The periodate oxidation and chromium chloride coupling methods were compared for their ability to sensitize indicator erythrocytes with staphylococcal lipoteichoic acid (LTA) for the detection of specific antibody. Erythrocytes, sensitized with periodiate-activated lipoteichoic acid, were found to be superior for use in both passive immune hemagglutination and hemolysis tests as well as in the technique of localized hemolysis-in-gel for the detection of specific antibody-producing cells against LTA.

Production and Properties of Antisera to Membrane Glycolipids of Mycoplasma pneumoniae.

The glycolipid haptens of Mycoplasma pneumoniae became immunogenic when bound to membrane proteins of Acholeplasma laidlawii by reaggregation. This process consisted of the solubilization of lipid-depleted A. laidlawii membranes and M. pneumoniae glycolipids in 20 mm sodium dodecyl sulfate and dialysis of the mixed solutions against 20 mm Mg(2+). The antibodies produced in rabbits to the reaggregated glycolipids inhibited the metabolism of M. pneumoniae, fixed complement with M. pneumoniae glycolipids or whole cells, precipitated M. pneumoniae glycolipids, and agglutinated M. pneumoniae cells. All these antibody activities could be blocked or absorbed by the purified glycolipids but not by a series of carbohydrates containing glucose and galactose. It was concluded that the antiserum to the reaggregated glycolipids may be regarded as a specific serum to membrane glycolipids of M. pneumoniae, since the antibodies to A. laidlawii membrane proteins, present in this serum, did not react with the glycolipids or with any other cell component of M. pneumoniae.