The handling of Listeria monocytogenes by macrophages: the search for an immunogenic molecule in antigen presentation

The activation of T lymphocytes for immunity to the intracellular pathogen Listeria monocytogenes requires that Ia-positive macrophages ingest the bacteria. The subsequent handling of Listeria by macrophages was examined in this report and related to antigen presentation to T cells. Macrophages pulsed with radiolabeled Listeria, besides releasing acid-soluble radioactivity--an indication of extensive catabolism of the Listeria-derived proteins--were also found to release acid-insoluble peptides. The rate of release of the peptides was not markedly affected by treatment with chloroquine, ammonia, or monensin and was independent of the state of activation and the level of Ia expression of the macrophage. The peptides were not associated with fragments of membranes and were represented by several molecular species. Listeria-derived peptides were also found associated with the macrophage plasma membrane. The membrane-associated peptides behaved like integral membrane proteins and could be released by proteases or detergents. Their expression was independent of the dose of Listeria and the level of Ia expression of the macrophage, and their presence could not be inhibited by protease inhibitors or chloroquine. The Listeria peptides released by the macrophages were very weakly immunogenic in a T cell proliferation assay. Purified plasma membranes from Listeria-pulsed macrophages, which contained membrane-associated Listeria peptides, were not immunogenic by themselves but could be reprocessed by additional macrophages to subsequently stimulate T cells. Trypsin treatment of Listeria-pulsed macrophages did not cause a significant reduction in their ability to stimulate T cells. No association was found between Ia molecules and either the membrane-associated or the released peptides with the use of several technical approaches. Hence, after internalization of Listeria, potentially immunogenic material can be found at the cell surface as well as in the culture fluid. The release of soluble peptides is a clear indication that proteins can be recycled after their internalization in vesicles.

The handling of Listeria monocytogenes by macrophages: the search for an immunogenic molecule in antigen presentation

The activation of T lymphocytes for immunity to the intracellular pathogen Listeria monocytogenes requires that Ia-positive macrophages ingest the bacteria. The subsequent handling of Listeria by macrophages was examined in this report and related to antigen presentation to T cells. Macrophages pulsed with radiolabeled Listeria, besides releasing acid-soluble radioactivity--an indication of extensive catabolism of the Listeria-derived proteins--were also found to release acid-insoluble peptides. The rate of release of the peptides was not markedly affected by treatment with chloroquine, ammonia, or monensin and was independent of the state of activation and the level of Ia expression of the macrophage. The peptides were not associated with fragments of membranes and were represented by several molecular species. Listeria-derived peptides were also found associated with the macrophage plasma membrane. The membrane-associated peptides behaved like integral membrane proteins and could be released by proteases or detergents. Their expression was independent of the dose of Listeria and the level of Ia expression of the macrophage, and their presence could not be inhibited by protease inhibitors or chloroquine. The Listeria peptides released by the macrophages were very weakly immunogenic in a T cell proliferation assay. Purified plasma membranes from Listeria-pulsed macrophages, which contained membrane-associated Listeria peptides, were not immunogenic by themselves but could be reprocessed by additional macrophages to subsequently stimulate T cells. Trypsin treatment of Listeria-pulsed macrophages did not cause a significant reduction in their ability to stimulate T cells. No association was found between Ia molecules and either the membrane-associated or the released peptides with the use of several technical approaches. Hence, after internalization of Listeria, potentially immunogenic material can be found at the cell surface as well as in the culture fluid. The release of soluble peptides is a clear indication that proteins can be recycled after their internalization in vesicles.

Separation of the immune response genes for LDH-B and MOPC-173. I. Description of an immune response defect in B10.BASR1

By using the intra-I-region recombinant mouse strain, B10.BASR1 (H-2as4), the immune response (Ir) genes for LDH-B and MOPC-173 were genetically and serologically separated, as assayed by T cell proliferation. Previous work demonstrated that the H-2s and H-2b strains respond to LDH-B and MOPC-173, whereas the H-2a and H-2k strains failed to respond due to haplotype-specific suppression of I-Ak-activated T helper cells by I-Ek-activated T suppressor cells. In the experiments reported here, B10.BASR1 mice, which lack I-Ek expression, mounted a significant T cell proliferative response to MOPC-173 but not to LDH-B. Separation of the Ia determinants used in restricting these two antigen responses was further confirmed when pretreatment of B10.S(9R) (A alpha sA beta sE beta sJk) macrophages with A.TL anti-B10.HTT (anti-A beta sE beta sJs) serum absorbed with B10.BASR1 spleen cells blocked the LDH-B response but not the MOPC-173 response. Unabsorbed serum blocked both antigen responses. The primary immunogenic determinant recognized by LDH-B or MOPC-173 immune T cells was not present on both antigens, as MOPC-173-primed T cells and LDH-B-primed T cells responded only to the priming antigen. Lastly, by using the A beta mutant strain, B6CH-2bm12, it was shown that the Ir gene and Ia determinants affected by this mutation had no effect on the LDH-B and MOPC-173 proliferative responses. These results suggest the possibility of an intragenic recombinatorial event in either the A alpha or A beta chain resulting in the separation of these two immune response gene functions.

Separation of the immune response genes for LDH-B and MOPC-173. I. Description of an immune response defect in B10.BASR1

By using the intra-I-region recombinant mouse strain, B10.BASR1 (H-2as4), the immune response (Ir) genes for LDH-B and MOPC-173 were genetically and serologically separated, as assayed by T cell proliferation. Previous work demonstrated that the H-2s and H-2b strains respond to LDH-B and MOPC-173, whereas the H-2a and H-2k strains failed to respond due to haplotype-specific suppression of I-Ak-activated T helper cells by I-Ek-activated T suppressor cells. In the experiments reported here, B10.BASR1 mice, which lack I-Ek expression, mounted a significant T cell proliferative response to MOPC-173 but not to LDH-B. Separation of the Ia determinants used in restricting these two antigen responses was further confirmed when pretreatment of B10.S(9R) (A alpha sA beta sE beta sJk) macrophages with A.TL anti-B10.HTT (anti-A beta sE beta sJs) serum absorbed with B10.BASR1 spleen cells blocked the LDH-B response but not the MOPC-173 response. Unabsorbed serum blocked both antigen responses. The primary immunogenic determinant recognized by LDH-B or MOPC-173 immune T cells was not present on both antigens, as MOPC-173-primed T cells and LDH-B-primed T cells responded only to the priming antigen. Lastly, by using the A beta mutant strain, B6CH-2bm12, it was shown that the Ir gene and Ia determinants affected by this mutation had no effect on the LDH-B and MOPC-173 proliferative responses. These results suggest the possibility of an intragenic recombinatorial event in either the A alpha or A beta chain resulting in the separation of these two immune response gene functions.

Bone marrow-derived macrophage as accessory cells in antigen-induced T cell proliferation. H-2I region requirements for L-glutamic60-L-alanine30-L-tyrosine10 response

Marrow stem cells cultured with L cell-conditioned medium were used to produce large numbers of macrophages free of contaminating lymphoid cells or granulocytes. Experiments were performed by using these bone marrow-derived macrophages (BMDM) as antigen-presenting cells (APC) for the terpolymer antigen L-glutamic60-L-alanine30-L-tyrosine10 (GAT). By using antigen-specific T cell proliferation, it was demonstrated that BMDM were equal to splenic macrophages in their capacity to present GAT. Furthermore, when BMDM were pretreated with alloantibodies specific for Ia antigens of the I-A subregion, the T cell proliferative response to GAT was inhibited. The I-A subregion is known to be the site of Ir gene regulation of the GAT response, and antibodies to other subregions had no inhibitory effect. Monoclonal antibodies recognizing a beta-chain product of the I-A subregion (Ia. 17) also inhibited the BMDM from effective antigen presentation. These results were similar to those obtained with purified splenic macrophages.

Bone marrow-derived macrophage as accessory cells in antigen-induced T cell proliferation. H-2I region requirements for L-glutamic60-L-alanine30-L-tyrosine10 response

Marrow stem cells cultured with L cell-conditioned medium were used to produce large numbers of macrophages free of contaminating lymphoid cells or granulocytes. Experiments were performed by using these bone marrow-derived macrophages (BMDM) as antigen-presenting cells (APC) for the terpolymer antigen L-glutamic60-L-alanine30-L-tyrosine10 (GAT). By using antigen-specific T cell proliferation, it was demonstrated that BMDM were equal to splenic macrophages in their capacity to present GAT. Furthermore, when BMDM were pretreated with alloantibodies specific for Ia antigens of the I-A subregion, the T cell proliferative response to GAT was inhibited. The I-A subregion is known to be the site of Ir gene regulation of the GAT response, and antibodies to other subregions had no inhibitory effect. Monoclonal antibodies recognizing a beta-chain product of the I-A subregion (Ia. 17) also inhibited the BMDM from effective antigen presentation. These results were similar to those obtained with purified splenic macrophages.

Role of I-J-subregion gene products in the regulation of macrophage-T-Lymphocyte interaction

Pretreatment of splenic macrophages with anti-Ia serum specific for the various known I subregions and complement deleted the macrophages required for an in vitro antibody response to burro erythrocytes. Antibodies directed at the gene products of the I-J subregion, however, were unique in that they did not require the presence of complement. When macrophages and macrophage depleted cells were obtained from strains B10.A(3R) and B10.A(5R) differing only at the I-J subregion, they could not be mixed in culture for an effective response. Differences at other I subregions using alternative strain combinations resulted in an enhanced response. These results suggest that the I-J subregion has a critical role in macrophage-T cell interaction.

Ameloblastic fibroma: report of case

A case of ameloblastic fibroma of the mandible in a 7-year-old girl is presented. The case is of interest because of the unusually large size of the lesion. The lesion was treated with conservative surgical enucleation. There has been no evidence of recurrence of the lesion during the 14-mongh postoperative period. The views expressed herein are those of the authors and do not necessarily reflect the view of the United States Air Force or the Department of Defense.

EPSDT- one quarter million screenings in Michigan

Since the spring of 1973, Michigan's EPSDT program has screened more than 300,000 children. The Department of Social Services contracted with the Department of Public Health to design the screening and referral parts of the program; in turn the Department of Public Health contracts with local health departments to do screening with one or more teams composed of a nurse, two technicians, and a clerk. The 72 teams screen 10,000 clients each month. More than one-half of these clients are referred for diagnosis and treatment. The highest percentage (27 per cent) of referral is for dental care; the second highest (26 per cent) is for immunization. Participation in the program of state and local social services departments, local health departments, and all groups of health providers has been excellent. There continues to be a high no-show for screening and a moderate no-show rate to providers for diagnosis and treatment. Evaluation of the program elements is needed.

Distribution and metabolism of diphenylhydantoin in oral and nonoral tissues of ferrets

Tissue distribution of diphenylhydantoin and metabolites in oral and nonoral tissues of the ferret after administration of single and multiple doses revealed that prolonged administration resulted in high concentrations of unmetabolized DPH in oral mucosa, salivary glands, and gingiva. This suggests a direct role of unmetabolized DPH in the induced gingival hyperplasia.

Mechanism of action of the fungicide thiabendazole, 2-(4'-thiazolyl) benzimidazole

Thiabendazole, 2-(4'-thiazolyl) benzimidazole (TBZ) inhibited the growth of Penicillium atrovenetum at 8 to 10 mug/ml. Oxygen consumption with exogenous glucose was inhibited at 20 mug/ml, but endogenous respiration required more than 100 mug/ml. TBZ inhibited completely the following systems of isolated heart or fungus mitochondria: reduced nicotinamide adenine dinucleotide oxidase, succinic oxidase, reduced nicotinamide adenine dinucleotide-cytochrome c reductase, and succinic-cytochrome c reductase at concentrations of 10, 167, 10, and 0.5 mug/ml, respectively. Cytochrome c oxidase was not inhibited. Antimycin A and sodium azide caused the usual inhibition patterns for both fungus and heart terminal electron transport systems. In the presence of antimycin, the fungicide inhibited completely succinate-dichloro-phenolindophenol reductase and succinate-2, 2-di-p-nitrophenyl-(3, 3-dimethoxy-4, 4-biphenylene-5, 5-diphenylditetrazolium)-reductase at 2 and 4 mug of TBZ per ml, respectively. Coenzyme Q reductase required 15 mug/ml. TBZ reduced the uptake by P. atrovenetum of glucose and amino acids and decreased the synthesis of various cell components. At 120 mug/ml, the incorporation of labeled carbon from amino acids-U-(14)C was decreased: lipid, 73%; nucleic acids, 80%; protein, 80%; and a residual fraction, 89%. TBZ did not inhibit peptide synthesis in a cell-free protein-synthesizing system from Rhizoctonia solani. Probably the primary site of inhibition is the terminal electron transport system and other effects are secondary.