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At least 19 recordsLinked to original sources
PubMed1992

Immunization with extracellular proteins of Mycobacterium tuberculosis induces cell-mediated immune responses and substantial protective immunity in a guinea pig model of pulmonary tuberculosis.

We have studied the capacity of a selected fraction of Mycobacterium tuberculosis extracellular proteins (EP) released into broth culture by mid-logarithmic-growth-phase organisms to induce cell-mediated immune responses and protective immunity in a guinea pig model of pulmonary tuberculosis. Guinea pigs infected with M. tuberculosis by aerosol but not uninfected control guinea pigs exhibit strong cell-mediated immune responses to EP, manifest by dose-dependent cutaneous delayed-type hypersensitivity and splenic lymphocyte proliferation. Guinea pigs immunized subcutaneously with EP but not sham-immunized control guinea pigs also develop strong cell-mediated immune responses to EP, manifest by dose-dependent cutaneous delayed-type hypersensitivity and splenic lymphocyte proliferation. EP is nonlethal and nontoxic to guinea pigs upon subcutaneous immunization. Guinea pigs immunized with EP and then challenged with aerosolized M. tuberculosis exhibit protective immunity. In five independent experiments, EP-immunized guinea pigs were consistently protected against clinical illness, including weight loss. Compared with EP-immunized guinea pigs, sham-immunized control guinea pigs lost 12.9 +/- 2.0% (mean +/- SE) of their total weight. EP-immunized guinea pigs also had a 10-fold reduction in viable M. tuberculosis bacilli in their lungs and spleens (P = 0.004 and 0.001, respectively) compared with sham-immunized control animals. In the two experiments in which some guinea pigs died after aerosol challenge, EP-immunized animals were protected from death. Whereas all 12 (100%) EP-immunized guinea pigs survived challenge with aerosolized M. tuberculosis, only 6 of 12 (50%) sham-immunized control guinea pigs survived challenge (P = 0.007, Fisher exact test). This study demonstrates that actively growing M. tuberculosis cells release immunoprotective molecules extracellularly, that a subunit vaccine against tuberculosis is feasible, and that extracellular molecules of M. tuberculosis are potential candidates for a subunit vaccine.

Aerosols↗
PubMed1992

Transmission immunity in malaria: reflections on the underlying immune mechanisms during natural infections and following artificial immunization.

Malaria transmission-blocking immunity has been studied in natural malarial infections in man, during infections in animals and following artificial immunization of animals with sexual stage malaria parasites. Effective immunity, which prevents infectivity of a malarial infection to mosquitoes, has been observed under all of these circumstances. Two general types of effector mechanism have been identified. One is an antibody mediated mechanism which acts against the extracellular sexual stages of the parasite within the midgut of a blood feeding mosquito. The other is a cytokine mediated mechanism which inactivates the gametocytes of the parasites while still in the circulation of the vertebrate host. Both effects have been observed during natural infections and following artificial immunization. The basis of induction of transmission-blocking immunity, including the nature of the memory for such immunity, however, may be very different in different host/parasite systems and during natural infection or following artificial immunization. Following artificial immunization a strong immune memory for transmission blocking immunity has been observed in animal systems. By contrast, following natural infections in man immune memory for transmission blocking immunity has been found to be weak and short lived if it occurs at all. It is suggested that the immunogens which induce natural transmission blocking immunity may be CD4+ independent.

Animals↗
PubMed1977

Immune response to immunization via the anterior chamber of the eye. I. F. lymphocyte-induced immune deviation.

The immunizing abilities of alloantigens placed within the anterior chamber of the eye have been studied in inbred rats. Although intracameral inoculation of F1 hybrid lymphocytes into parental strain recipients elicited both cell- and antibody-mediated immunity, a delimited interval was identified postinoculation during which the systemic cell-mediated immune response was suppressed as indicated by prolonged acceptance of orthotopic skin allografts. The prompt appearance of hemagglutinating antibodies in the serum of immunized rats followed a time course which coincided with the suppression of cell-mediated immunity and suggested that the two events are casually related. Since exposure to allogeneic antigens on lymphoid cells via the anterior chamber elicits a transient suppression in cell-mediated immunity, where humoral immunity is preserved, the phenomenon resembles immune deviation.

Animals↗
PubMed1975

Immune complexes in the spleen. Replacement of immune complexes trapped in spleen follicles by new immune complexes from the circulation.

The fate of intravenously injected 125I-BGG-anti-BGG in the spleen of mice was studied using autoradiography. Part of the labelled immune complexes was trapped in the follicles of the spleen as could be expected. In a first experiment it was found that injections with unlabelled immune complexes were followed by a partial release of the labelled immune complexes from the follicles. In a second experiment unlabelled immune complexes retained in spleen follicles appeared to inhibit the trapping of intravenously injected labelled immune complexes to some degree and for some time. The conclusion was drawn from these experiments that immune complexes, which normally remain in part of the lymphoid follicles for a long period, may be replaced by new immune complexes from the circulation. This seems important since trapping in lymphoid follicles of antigen complexed by antibody is the only known mechanism by which small amounts of antigen may be preserved in the body for a long time after the initiation of antibody production. The bulk of antigen and antigen-antibody complexes is removed by phagocytosis followed by destruction. It appeared also that, although all spleen follicles in the mouse spleen is able to retain the complexes for a longer time. Possible explanations for these individual differences between the follicles of one spleen are discussed.

Animals↗
PubMed1975

Immunity to Toxoplasma gondii induced in vitro in non-immune mouse macrophages with specifically immune lymphocytes.

Male and female CBA mice were used to study in vitro the mechanisms involved in the development and expression of cellular immunity to toxoplasma infection. The lag phase preceding toxoplasma division was delayed in nonimmune macrophages obtained from peritoneal cavities stimulated with thioglycollate. Specific anti-toxoplasma activity was conferred on nonimmune macrophages incubated with toxoplasma-immune spleen lymphocytes and soluble toxoplasma antigen. Treatment of immune spleen cell populations with anti-theta serum plus complement abolished completely their activity of conferring anti-toxoplasma activity on nonimmune macrophages, demonstrating that the essential cells were T lymphocytes. The mediator(s) responsible for the acquisition of immunity to toxoplasma in the nonimmune macrophages were soluble. Heat-inactivated, toxoplasm-immune macrophages of fibroblasts. The findings are related to previous investigations of induced immunity in animals and man.

Animals↗
PubMed1976

Comparison of the humoral and cellular immune response after immunization with live, UV inactivated herpes simplex virus and a subunit vaccine and efficacy of these immunizations.

Antibody and cell-mediated immune responses were measured in rabbits immunized with live, UV inactivated herpes simplex virus or with a subunit vaccine containing envelope proteins. All the types of immunization procedures induced the production of antibody as well as a specific cellular immunity. Furthermore, the subunit vaccine was as effective as the immunization with live or UV inactivated virus to prevent death upon challenge with live HSV. Live HSV induced a transient unresponsiveness of both B and T cells to in vitro stimulation with various mitogens.

Animals↗
PubMed1992

A 2-year follow-up of an anti-HIV immune reaction in HIV-1 gp160-immunized healthy seronegative humans: evidence for persistent cell-mediated immunity.

The first trial of an anti-HIV immunization, using a recombinant vaccinia virus expressing gp160 (rV) for priming and paraformaldehyde-fixed rV-infected PBLs and soluble gp 160 for boosting, clearly showed an in vitro HIV-protective immune reaction. This result led us to carry out an additional 2 year Phase I clinical trial in 25 HIV-seronegative volunteers, using HIV gp 160 antigens for immunization in four different protocols. The 2 year trial showed (a) the safety of the preparations, (b) a transient humoral immunity following each boost, and (c) a long-lasting memory T-cell response. Memory cytotoxic T-lymphocytes (CTLs) induced by gp 160 antigen with or without vaccinia vector lysed HLA class I restricted target cells expressing HIV-1 env antigens. These results are consistent with CTLs being an effective component of an AIDS vaccine to control cell-to-cell viral replication, dissemination in the organism, and subsequent evolution toward AIDS.

AIDS Vaccines↗
PubMedDate not supplied

The immune system and intravenous administration of immune globulin. Part I, The immune system.

Interest in the immune response has greatly increased, mostly because of the discovery of the AIDS virus. An understanding of the basic function of the normal human immune system is vital knowledge for today's nurse. Part 1 of this article describes normal immune response as well as abnormal immune system function, and correlates this information with the clinical picture of the patient.

Antibody Formation↗
PubMed1979

Functional activation of immune lymphocytes by antigenic stimulation in cell-mediated immunity. IV. Role of macrophage and its soluble factor in antigen-induced MIF production of immune T lymphocytes.

Histocompatibility-linked restriction of macrophage-T lymphocyte interaction in antigen-induced MIF production by sensitized lymphocytes was examined, by using combinations of inbred strain 2, strain 13, and JY-1 guinea pigs. The effective interaction of the antigen-bearing macrophages with the immune T lymphocytes was observed when the donor of the antigen-bearing macrophages and that of the immune lymphocytes shared Ia antigens of the major histocompatibility complex. Identities of B antigens and S antigens were not important for this cooperation. It was further demonstrated that the previously reported soluble factor derived from LPS-stimulated peritoneal adherent cells (macrophages) could help antigenic activation of the immune lymphocytes across the strain barrier provided a small number of macrophages (0.01%) from syngeneic strain were present. These results show that the presence of macrophages is absolutely required to present antigen to immune T lymphocytes in a genetically restricted manner and the soluble factor from macrophages appears to give a nonspecific effect on the lymphocyte activation in addition to or in collaboration with antigenic stimulation.

Animals↗
PubMed1975

Immune plasma-dependent cytotoxicity of immune and non-immune peripheral lymphoid cells for target cells coated with bacterial outer unit membrane.

The development of a model system for use in the study of lymphoid cell cytotoxicity to bacterial membrane antigens was attempted. In this system 51 Cr-labelled chicken red blood target cells were coated with pieces of the outer unit membrane of leptospirae rather than with soluble antigens. Using the model system to study dog peripheral immune lymphoid cell cytotoxicity to coated target cells we found that both immune and non-immune lymphocytes are antibody dependent for the expression of their cytotoxicity. It was also found that the unit membrane preparation from leptospirae can serve as a good antigenic stimulant to immune dog lymphoid cells as measured by increased [3H]thymidine uptake.

Animals↗
PubMed1979

Experimental glomerular lesions induced by chronic immune complex formation. I. Formation and elimination of the immune complex (relationship between the immune status and the glomerular changes).

Chronic immune complex formation was induced in rabbits by daily administration of 12.5 g bovine serum. In good antibody producer animals immediate immune complex production and elimination from the circulation were demonstrable. This was followed within a few minutes by the appearance of free 125I in fairly large amounts in blood, as a sign of immediate phagocytosis and disintegration of the 125I-labelled immune complexes. Phagocytic activity decreased in the host animal during chronic heteroprotein administration in every case. The earliest glomerular changes were those of exudative glomerulonephritis, the extent of which depended on the antibody productivity of the animal. Persistent immunocomplexaemia induced by administration of the antigen over 60 and 100 days, respectively, resulted in mesangioproliferative glomerulonephritis in 7, in membranoproliferative glomerulonephritis in 3, and in membraneous glomerulonephritis in 1 out of 11 laboratory animals.

Animals↗
PubMed1978

Immune response to immunization via the anterior chamber of the eye. II. An analysis of F1 lymphocyte-induced immune deviation.

Exposure to alloantigen via the anterior chamber of the eye elicits a transient suppression of cellular immunity, whereas humoral immunity is preserved--i.e. F1 LI-ID. The majority of lymphoid cells inoculated into the anterior chamber are retained within the posterior segment of the eye. The latter serves as a depot of alloantigen, allowing the chronic egress of small numbers of cells into the vascular tree. The persistence of this antigen depot is essential to the development of F1 LI-ID. Since there is a preferential distribution of cells that migrate from the eye to the spleen, the functional integrity of the latter is also necessary to elicit F1 LI-ID. It is concluded that an anatomically intact spleen, i.v. presentation of antigen, and persistence of antigen within the eye are all important to the elicitation of this phenomenon.

Animals↗
PubMed1979

Purification of soluble immune complexes from serum using polymethylmetacrylate beads coated with conglutinin or C1q. Application to the analysis of the components of in vitro formed immune complexes and of immune complexes occurring in vivo during leishmaniasis.

A procedure for the isolation of immune complexes from human sera has been developed. Two steps are involved: (1) lipid-free serum is precipitated by polyethylene glycol; (2) the solubilized precipitate is absorbed on a column of polymethylmethacrylate beads coated with conglutinin (K) or C1q; the column is washed, the complexes are then eluted, using 0.02 M EDTA (for K column) or 0.5 M NaCl (for C1q column). This procedure permitted the purification and the characterization of soluble 125I-BSA-anti-BSA, 125 I-tetanus toxoid-anti-tetanus toxoid, and 125-I-HBsAg-anti-HBsAg complexes made in vitro in the presence of fresh human serum. The isolated complexes were shown to contain antigen, antibody, C1q, C1r, C1s and C3. When normal human serum was submitted to such a procedure, no detectable amount of protein was present in the final eluted fraction. Immune complexes formed in vivo were also purified by conglutinin column from the serum of a patient with disseminated leishmaniasis. The isolated material was found to contain IgM, IgG, C1q, C1r, C1s, C3c and C3d. The purified complexes dissociated at acid pH were found to contain anti-IgG and anti-leishmania antibodies.

Adult↗
PubMed1991

Vaccination with the major secretory protein of Legionella induces humoral and cell-mediated immune responses and protective immunity across different serogroups of Legionella pneumophila and different species of Legionella.

In a previous study, we demonstrated that immunization of guinea pigs with the major secretory protein (MSP) of Legionella pneumophila, serogroup 1 induced humoral and cell-mediated immune responses to MSP and protective immunity against lethal aerosol challenge with this serogroup of L. pneumophila. Although serogroup 1 L. pneumophila cause most cases of Legionnaires' disease, other serogroups of L. pneumophila and species of Legionella cause many cases. In this study, we have examined if immunization with MSP induces humoral and cell-mediated immune responses and protective immunity across different serogroups of L. pneumophila and species of Legionella. By immunoblot analysis, MSP from L. pneumophila serogroup 1 (Lp1 MSP), L. pneumophila serogroup 6 (Lp6 MSP), and Legionella bozemanii (Lb MSP) shared common epitopes recognized by guinea pig anti-Lp1 MSP antiserum. These MSP molecules, however, were not identical as they had different apparent m.w. Immunization of guinea pigs with MSP induced strong cell-mediated immune responses across the different serogroups and species, as indicated by splenic lymphocyte proliferation and cutaneous delayed-type hypersensitivity in response to both homologous and heterologous MSP. Immunization with MSP induced strong protective immunity across two serogroups of L. pneumophila; overall, 9 survived aerosol challenge with L. pneumophila serogroup 1 compared to 0 of 12 (0%) sham-immunized control animals (p = 3 x 10(-4), Cochran-Mantel-Haenzel chi 2 statistic for pooled data). Immunization with MSP also induced protective immunity across species of Legionella but protection was species-specific. Whereas immunization with Lb MSP induced protective immunity against L. pneumophila, neither immunization with Lp1 MSP nor immunization with Lb MSP induced protective immunity against L. bozemanii, which produces MSP. Not surprisingly, immunization with MSP did not induce protective immunity against MSP-negative Legionella micdadei. In the case of both L. bozemanii and L. micdadei, immunization with a sublethal dose did confer protective immunity to aerosol challenge indicating that these species do contain immunoprotective components. This study demonstrates that immunization with MSP induces humoral and cell-mediated immune responses across different serogroups of L. pneumophila and species of Legionella, but that the capacity of MSP immunization to induce protective immunity is species-specific. Nevertheless, an MSP vaccine has the potential to induce protective immunity against the great majority of cases of Legionnaires' disease.

Aerosols↗
PubMed1976

The immune response in cirrhotic rats. Antigen distribution, humoral immunity, cell-mediated immunity and splenic suppressor cell activity.

The immunological disturbances occurring as a result of liver disease have been studied in an animal model of cirrhosis. The mononuclear phagocytic cells of the normal liver phagocytose large amounts of antigen irrespective of whether that antigen is injected directly into the portal or into the systemic circulations. The liver therefore acts as a filter 'in series' and 'in parallel' with the spleen and reduces the immunogenicity of antigens entering the organism by either of these routes. In rats with hepatic cirrhosis, there is a reduction in the capacity of the liver to phagocytose the flagellar antigen of Salmonella adelaide. This results in increased stimulation of splenic lymphoid tissue and in an increased antibody response to this thymus-independent antigen. The increased antigenic stimulus to the spleen may also be responsible for the increased suppressor-cell activity which has been demonstrated in these rats, and may be the mechanism of the diminished cell-mediated immune response both in this animal model of cirrhosis and in the human disease state. These studies suggest that many of the immunological disturbances associated with chronic liver disease may be the result of maldistribution of antigen occurring because of impaired hepatic phagocytic capacity.

Animals↗
PubMed2026

Immune subtyping of colorectal adenoma identifies a subtype with activated adaptive immunity ahead of progressing to cancer.

BACKGROUND: Colorectal adenomas (CRA) represent precursor lesions with varying risks of malignant transformation. However, molecular subtyping, particularly immune-related classification, remains underexplored in adenomas. This study aims to characterize the immune landscape of CRA through immune subtyping and evaluate its association with cancer progression, gene expression signatures, and functional pathways. METHODS: We conducted a retrospective analysis of transcriptomic data from multiple cohorts of CRA samples. Immune subtypes were identified using non-negative matrix factorization (NMF) based on immune-related genes. Diverse deconvolution algorithms were used to estimate immune cell infiltration. The immune status alteration in premalignant lesion was further consolidated by single-cell transcriptome data. Differential gene expression analysis was performed between subtypes, followed by functional enrichment analyses (Gene Ontology [GO] and Kyoto Encyclopedia of Genes and Genomes [KEGG]). RESULTS: Two distinct immune subtypes were identified: an immune-enriched subtype characterized by high lymphocyte infiltration and elevated expression of immune-related genes, and an immune-deficient subtype with suppressed immune activity. Differential expression analysis revealed significant upregulation of immune response genes (e.g., CD4, CD86, HLA-DRA) in the immune-enriched subtype. GO and KEGG analyses highlighted enrichments in leukocyte transendothelial migration, chemokine signaling, and antigen processing and presentation pathways. Single-cell result revealed an early occurrence of TIGIT activation and exhausted CD8 T cell features in adenoma when compared to normal tissue. CONCLUSION: This study delineates distinct immune subtypes within CRAs. The immune-enriched subtype demonstrates activated adaptive immunity and may reflect a higher potential for immune surveillance, while the immune-deficient subtype exhibits stromal features suggestive of progressive transformation. These findings provide insights into early immune microenvironment alterations and may inform strategies for risk stratification and immunoprevention in colorectal carcinogenesis.

Colorectal adenoma↗
PubMed1992

Defence mechanisms and immune evasion in the interplay between the humane immune system and Plasmodium falciparum.

Immunity to P. falciparum malaria is developed as a result of long term exposure to the parasite and depends on immunological memory. The key directors in immune recognition and regulation of the immunological responses are the T-cells. It seems reasonable to propose that immunity is acquired when a critical mass of T-cells, recognizing relevant malaria antigens, has been developed. These T-cells mediate immunity by regulating macrophage and B-cell activity, but they may also act directly as cytotoxic cells on infected hepatocytes and through production of parasite-toxic cytokines. The potential immune effector mechanisms against P. falciparum are many. The relative importance of each in protection is unknown and protection seems to be mediated through different mechanisms according to the degree of exposure to malaria and the pattern of malaria transmission. Since immunity to malaria is not an absolute phenomenon, many effector mechanisms are probably working together in (partially) protected individuals. Immunity to P. falciparum is acquired after years of exposure to the parasite and several disease episodes. The protracted course to clinical immunity indicates that the parasite interfere with development of immunity. Several mechanisms seem to be operating. 1) Induction of the immune response to some macromolecules is avoided because the parasites are living inside host cells during part of their life cycle, and the reaction to other molecules is apparently avoided by mimicry of host molecules. 2) Immune recognition is hampered by the extraordinary diversity of antigen phenotypes in the parasite population. 3) Immune regulation is obstructed by immune suppression. During P. falciparum malaria such suppression is characterized by a profoundly diminished in vitro proliferative response to malaria antigens, which probably is precipitated by defects in the early events of T-cell activation and inhibition of IL-2 function elucidated, but soluble factors secreted either by the parasites, or by host cells as a result of exposure to the parasite, seem to be involved. 4) Immune effector mechanisms in the liver and the spleen are avoided by sequestration of the mature parasites to the vascular endothelium. The interplay between the human defence system and the malaria parasite governs the symptomatology, the pathology and the development of immunity to the disease. These interactions are extremely complex, and only partly understood. Figure 1 summarizes my view on how these interactions could explain the characteristics of acquired immunity to P. falciparum.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗