George Caldes

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.

Chemical Studies of Paolin II, an Antiviral Substance from Oysters

Summary An antiviral thermostable substance (paolin II) is isolated from oysters by extraction with acetic acid followed by fractional precipitation with ethanol. The substance shows one peak on ultracentrifugation, has a sedimentation constant of 1.6-1.8 and a molecular weight of approximately 10,000. The material yields 16 amino acids on hydrolysis with a composition of 8.6% nitrogen and 23.4% carbohydrate, indicating the mucoprotein nature of the substance. The authors are indebted to A.M. Young, Division of Biologies Standards, Laboratory of Biophysics and Biochemistry, for his technical assistance with the sedimentation studies.

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.

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 α(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.

Mycoplasma pneumoniae phosphatidyl glycerol.

Summary When the lipids of M. pneumoniae were fractionated by silicic acid column chromatography, the major serologically reactive material was usually eluted with chloroform-methanol, 9:1. Initially or after rechromatography the 9:1 eluates contained primarily a phospholipid moiety which on chemical analysis appeared to be phosphatidyl glycerol. Although this phospholipid did not react with M. pneumoniae antibodies, it acted as an auxiliary lipid to enhance the activity of the glycolipid haptens which were present in low concentration in the 9:1 eluates.

Chemical Studies of an Antitumor Substance from African Onions

Conclusion An antitumor substance has been isolated and fractionated from the bulb of the African onion. Antitumor activity of this material against Walker 256 (intramuscular) carcinosarcoma was demonstrated.

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.

A comparison of the chemical composition of Mycobacterium tuberculosis muris with Mycobacterium tuberculosis bovis (BCG).

Abstract Comparative chemical analyses were performed on Mycobacterium tuberculosis bovis (BCG) and M. tuberculosis muris organisms grown under the same conditions. The amino acid contents were similar. The same carbohydrates were found in both organisms. However, the muris bacillus had twice as much glucose as the BCG. The BCG organism contained more lipid, and had four times more material extractable by chloroform, than the muris bacillus.