The role of non-type-specific protein antigens of the cell wall in Streptococcus group A in developing delayed hypersensitivity

The role of the type-nonspecific (TNS) cell-wall antigens of group A streptococci has been determined. The study has been made on guinea pigs sensitized with whole microbial cells or HCl extracts containing TNS antigens. To determine delayed hypersensitivity, the in vitro cytotoxic test on adhering lymph-node cells in the autologous system has been used. The study has shown that sensitization with group A streptococci of different types or with TNS antigens induces the development of delayed hypersensitivity to TNS antigens (or antigen), common for different types of group A streptococci, but specific for this group. HCl extracts containing TNS antigens can be recommended as the preparation for testing delayed hypersensitivity to antigens, specific for group A streptococci.     

Ultraviolet radiation and the contact hypersensitivity reaction in mice

The article reviews the application of the contact hypersensitivity assay in mice to the science of photoimmunology. The contact hypersensitivity (CHS) reaction, which is suppressed by UV irradiation in mice similarly to their ability to respond immunologically to skin tumors, has been used very profitably to reveal many of the regulating factors that control photoimmunosuppression, such as the identity of the photoreceptors that initiate immunosuppression, the defects induced in the cutaneous antigen presenting pathway, the local cytokine imbalance, and the protective intervention by various molecules, drugs, or interacting UV wavebands. Technical hints to optimize the measurement of the CHS response are suggested, including information on UV radiation wavebands and dosages and sensitivities of different mouse strains.     

Migration Inhibition Studies on Peripheral Leukocytes and Lymph Node Cells from Ruminants with Fascioliasis

Delayed type hypersensitivity against antigens of Fasciola hepatica has been repeatedly documented in infected hosts. Evidence has been presented to suggest that the delayed reactivity may develop earlier in the regional lymph nodes of the parasitized organ than in other lymph nodes of the body (Soulsby 1971).     

The nonspecific changes in the immune system to the administration of the membrane-ribosomal fraction of the causative agent of pseudotuberculosis

Nonspecific changes in different elements of the immune system of animals under the action of Y. pseudotuberculosis membrane-ribosomal fraction (MRF) with high protective potency have been studied for the purpose of the analysis of the preparation for immunological safety. MRF has been shown to produce no changes in humoral immune response to antigens of different nature or to enhance this response, to produce no essential effect on the intensity of the reaction of delayed hypersensitivity to sheep red blood cells and to stimulate phagocytic processes in peritoneal macrophages and polymorphonuclear leukocytes.     

Comparative characteristics of the diagnostic properties of staphylococcal allergens in an experiment

The diagnostic value of five staphylococcal allergens prepared from a single S. aureus strain by different methods and in different institutions has been tested on the experimental models of delayed, immediate and mixed (immediate and delayed) hypersensitivity in guinea pigs. The advantages of the allergens prepared in Kazan (USSR) for the detection of delayed hypersensitivity and the ultrasonicated allergen, as well as the allergen made in Czechoslovakia, for the detection of immediate hypersensitivity have been noted.     

Delayed hypersensitivity to the antigens of the herpes simplex virus and herpetic resistance induced in mice by the administration of xenogeneic lymphocytic ultrafiltrates

Experiments on mice have shown that ultrafiltrates, prepared from lymphocytes obtained from the spleen of horses immunized with herpes vaccine and from human tonsils, contain herpes-specific transfer factor inducing delayed hypersensitivity. The antiherpetic resistance of mice has been found to achieve its maximum if herpes simplex antigens are introduced after the injection of the preparation of transfer factor.     

Heterologous antigenic stimulation in induction of delayed hypersensitivity.

An influence of a delayed hypersensitive reaction to a primary antigen on the induction of delayed hypersensitivity to a second unrelated antigen was observed in guinea pigs immunized with azobenzenearsonate-N-acetyl-L-tyrosine (ABAT), and injected intradermally 3 weeks later with a mixture of ABAT and secondary antigen. Animals so treated developed delayed hypersensitivity to sheep red blood cells (SRBC) or Type II pneumococcal polysaccharide as secondary antigens, as measured by skin test reactivity and inhibition of macrophage migration, whereas ABAT unsensitized control groups did not. However, attempts to induce delayed reactivity to proteins as secondary antigens were unsuccessful. The injection of secondary antigen into a mineral oil-induced inflammatory lesion did not induce delayed hypersensitivity, suggesting that specific reactivity to ABAT is a prerequisite for heterologous induction. Possible mechanisms for the observed phenomenon, including a role for macrophages, are discussed.     

Immunity to Epstein-Barr virus in Hodgkin's disease preceded by infectious mononucleosis

A patient who developed Hodgkin''s disease four years after infectious mononucleosis had elevated serum antibody titres to Epstein-Barr virus and delayed hypersensitivity reactions to membrane antigens prepared from fresh autologous spleen, from spleen cells of another Hodgkin''s patient, and from cell lines known to carry the Epstein-Barr virus genome. Additional studies in more lymphoma patients will be needed to determine the significance of the reactivity against tumour and virus-associated antigens which has been documented in this patient.     

Specific immunoprophylaxis in experimental tumour-host systems.

A variety of animal species have been rendered resistant to syngeneic tumours of many histologic types of immunoprophylaxis. Among the types of preparation of tumour-associated antigens that have merit as vaccines are tumour cells treated with radiation, mitomycin C, certain viruses, neuraminidase, sulfhydryl blocking agents and lipoidal reagents. Alternatively, tumour-associated antigens of the cell membrane may be solubilized and used for vaccination. Recent studies with dimethyldioctadecylammonium bromide (DDA) indicate that it both modifies tumour cells and serves as an immunologic adjuvant in that it enhances protective responses to iodoacetamide-treated lymphoma cells and acts as a potent macrophage activator. By judicious application of DDA either delayed hypersensitivity or antibody response may be selectively enhanced. Several advantages of DDA over other adjuvants are its water solubility, the fact that it does not produce deleterious lesions at the site of injection and the fact that it eliminates the risk of systemic infection that exists with the use of live bacteria.     

Relationship of the sensitizing and protective properties of pertussis antigens

When comparing delayed hypersensitivity (DN) to B. pertussis corpuscular antigens with the agglutinogenic composition of B. pertussis, as well as to its histamine-sensitizing, leukocyte-sensitizing, adjuvant and hemagglutinating activity, no correlation was detected between the specific sensitizing properties of these antigens and the serotype and studied nonspecific properties of B. pertussis. The DH level correlated with the protective activity of B. pertussis corpuscular antigens and the ultrasonic fractions of B. pertussis. The close correlation of these two phenomena suggest that DH-inducing and protective B. pertussis antigens are identical, though their action has different manifestations, depending on the method of administration of the antigen preparation. On these grounds a new method for evaluating the immunogenicity of B. pertussis antigens is proposed. This method consists in comparing the sensitizing activity of the antigen under test and that of the national standard.     

Exposure to ultraviolet radiation causes dendritic cells/macrophages to secrete immune-suppressive IL-12p40 homodimers

UV-induced immune suppression is a risk factor for sunlight-induced skin cancer. Exposure to UV radiation has been shown to suppress the rejection of highly antigenic UV-induced skin cancers, suppresses delayed and contact hypersensitivity, and depress the ability of dendritic cells to present Ag to T cells. One consequence of UV exposure is altered activation of T cell subsets. APCs from UV-irradiated mice fail to present Ag to Th1 T cells; however, Ag presentation to Th2 T cells is normal. While this has been known for some time, the mechanism behind the preferential suppression of Th1 cell activation has yet to be explained. We tested the hypothesis that this selective impairment of APC function results from altered cytokine production. We found that dendritic cells/macrophages (DC/Mphi) from UV-irradiated mice failed to secrete biologically active IL-12 following in vitro stimulation with LPS. Instead, DC/Mphi isolated from the lymphoid organs of UV-irradiated mice secreted IL-12p40 homodimer, a natural antagonist of biologically active IL-12. Furthermore, when culture supernatants from UV-derived DC/Mphi were added to IL-12-activated T cells, IFN-gamma secretion was totally suppressed, indicating that the IL-12p40 homodimer found in the supernatant fluid was biologically active. We suggest that by suppressing DC/Mphi IL-12p70 secretion while promoting IL-12p40 homodimer secretion, UV exposure preferentially suppress the activation of Th1 cells, thereby suppressing Th-1 cell-driven inflammatory immune reactions.     

Studies on circulating gonococcal antibodies and antigens.

One hundred human sera obtained from acute gonococcal disease and 100 sera from nongonococcal diseases or healthy persons were concentrated four times and examined for the presence of circulating gonococcal antigens and antibodies by means of a counterimmunoelectrophoresis (CIE) and delayed hypersensitivity assay. Antibodies reacting with cytoplasmic gonococcal antigens were detected by CIE in 92% of sera received from patients suffering from acute gonococcal disease. Gonococcal antigens were found in the concentrated sera of 82.3% of patients on the basis of dermal reactions observed upon injections of these sera into the skin of rabbits sensitized with disrupted gonococci; 51.8% of the patients' sera gave delayed hypersensitivity reactions in rabbits sensitized with cytoplasmic antigens of N. gonorrhoeae. Control sera from healthy people and those with non-gonococcal diseases did not react with any of the preparations tested.     

Radiation-Sensitive Mutants of Arabidopsis Thaliana

Five Arabidopsis mutants have been isolated on the basis of hypersensitivity of leaf tissue to UV light. For each mutant, the UV-hypersensitive phenotype (uvh) was inherited as a single recessive Mendelian trait. In addition, each uvh mutant represented a separate complementation group. Three of the mutations producing the UV hypersensitive phenotype have been mapped relative to either genetic markers or physical microsatellite polymorphisms. Locus UVH1 is linked to nga76 on chromosome 5, UVH3 to GL1 on chromosome three, and UVH6 to nga59 on chromosome 1. Each uvh mutant has a characteristic pattern of sensitivity based on UV sensitivity of leaf tissue, UV sensitivity of root tissue, and ionizing radiation sensitivity of seeds. On the basis of these patterns, possible molecular defects in these mutants are discussed.     

Detection of antibody responses and delayed dermal hypersensitivity with Blastomyces dermatitidis yeast and mycelial lysate antigens

Yeast cell lysate and mycelial lysate antigens prepared from one strain (T-58) of Blastomyces dermatitidis were evaluated with respect to the detection of antibodies and delayed dermal hypersensitivity. Comparable ELISA sensitivity values were evidenced with the two antigens when assayed against serum specimens from dogs with blastomycosis, sera from non-infected dogs residing in endemic and nonendemic areas for blastomycosis and sera from rabbits that were hyperimmunized with B. dermatitidis antigens. Specificity determinations with anti -Histoplasma capsulatum rabbit sera indicated that both reagents exhibited only minimal cross-reactivity; the mycelial antigen was slightly more specific than the yeast phase reagent. Similar sensitivity and specificity results were experienced when the two antigens were used to detect delayed dermal hypersensitivity in guinea pigs previously sensitized with B. dermatitidis or H. capsulatum.     

Immunoregulatory activity of the lungs in relation to corpuscular and soluble antigens

The immunoregulatory activity of the lungs in normal Wistar rats has been evaluated by difference between primary and secondary immune response to the same dose of the antigen introduced into the respiratory tract or intravenously. As shown in this investigation, intratracheal immunization with corpuscular antigens is accompanied by faintly pronounced antibody formation and a high degree of delayed hypersensitivity, while the introduction of soluble antigens into the respiratory tract leads to the active production of antibodies. The immunoregulatory activity of the lungs is T-dependent. The preliminary introduction of corpuscular or soluble antigen into the respiratory tract is accompanied by the formation of the local mechanism in the lungs for suppressing immune response to the subsequent intratracheal immunization.     

Mutants of Yeast Sensitive to Ultraviolet Light

Six uvr mutants of Saccharomyces cerevisiae with hypersensitivity to ultraviolet (UV) light were isolated after mutagen treatment with ethylmethanesulfonate. UV sensitivity ranges from moderate to extreme, and four of the mutants are also sensitive to nitrous acid. Ranking in terms of UV sensitivity does not parallel ranking in terms of nitrous acid sensitivity. Homozygous diploid mutant strains are somewhat less sensitive than the corresponding haploids. All mutations are recessive. None of the mutants is sensitive to gamma rays, and each shows photoreactivation after UV radiation. Complementation tests and tetrad analysis indicate that each strain represents mutation in a different gene. Two of the uvr genes are linked, and two others are centromere-linked.     

Delayed reproductive death and ROS levels in the progeny of irradiated melanoma cells

The cell death and survival of proliferating (clonogenic) cells were investigated in two human melanoma cell lines to assess the optimal conditions for preparation of apoptotic bodies from melanoma cells. After 50 J/m2 UVB+UVC the maximal levels of apoptotic cells assayed by Trypan blue staining, nucleosomal DNA fragmentation, MTT, and TUNEL tests were observed within 2-3 d of radiation. In 100 Gy gamma-irradiated cultures these apoptosis indicators were delayed for up to 3 weeks. In addition, clonogenic cells were observed only in exponentially growing cultures irradiated with UV at high cell density but not in gamma-irradiated cultures. The response of melanoma cultures after high UV radiation doses contrasted to the response in lethally gamma-irradiated cultures. UV-irradiated melanoma cultures were recovered within two weeks. Most of the clonogenic cells in the recovered colonies contained micronuclei. ROS levels determined by DCF fluorescence and a modified MTT test were also normalized obviously due to the extensive antioxidant defense system of melanoma cells. UV radiation of tumor cells might be the preferential method for preparation of apoptotic bodies. The presence of clonogenic cells in the suspension of apoptotic bodies from melanoma cells used for pulsing of dendritic cells with tumor antigens might compromise this protocol for preparation of cell vaccines.     

Dds20 operates in cds1-independent mechanism of tolerance to UV-induced DNA damage in Schizosaccharomyces pombe cells

Repair of DNA double-stranded breaks caused by ionizing radiation or cellular metabolization, homologous recombination, is an evolutionary conserved process controlled by RAD52 group genes. Genes of recombinational repair also play a leading role in the response to DNA damage caused by UV light. Cells with deletion in gene dds20 of recombinational repair were shown to manifest hypersensitivity to the action of UV light at lowered incubation temperature. Epistatic analysis revealed that dds20+ is not a member of the NER and UVER gene groups responsible for the repair of DNA damage induced by UV light. The Dds protein has functions in the Cds1-independent mechanism of UV damage tolerance of DNA.     

不同纯度、剂量白喉类毒素对迟发型超敏反应的影响

研究不同剂量及不同白喉类毒素纯度引起的迟发型超敏反应的状况,用于指导疫苗的生产,提高疫苗的质量。以豚鼠为动物模型,采用迟发型超敏试验法,对原制白喉类毒素、精制白喉类毒素、纯化精制白喉类毒素、高纯度的精制白喉类毒素的剂量与超敏反应试验。试验结果表明,注射白喉类毒素剂量的大小与超敏反应成正相关,与纯度成负相关。剂量越大,超敏反应越强;纯度越高,超敏反应愈弱。