Ultrastructural Features of Host-Parasite Relationship in Oral Candidiasis

In oral candidiasis, many keratinized epithelial cells and cells of Candida albicans are shed. Scales from patients with oral candidiasis were used for electron microscopic study of the epithelial-fungal relationship. Scales, scraped from the tongue and oral mucosa, were fixed for fungi. Electron microscopic observations showed cells of C. albicans outside, penetrating, or within the epithelial cells. Extracellular fungi possessed a floccular material adherent to the outer surface of the cell wall. Intracellular fungi lacked the floccular material which appeared to detach as fungi invaded the epithelial cells. Large vacuoles, which sometimes contained myelin figures, occupied the cytoplasm of fungal cells. Epithelial cells frequently contained several fungi. Discontinuous plasma membranes marked sites of fungal entry. Cytoplasmic areas devoid of fungi showed many tonofibrils, but the cytoplasm adjacent to fungi often lacked tonofibrils. Micrographs suggested that fungal cells lysed the tonofibrils. Bacteria were abundant in the scrapings, but always occupied an extracellular position.     

Control of Tissue Reactions in Monkeys Vaccinated with Viable Coccidioides immitis by Prevaccination with Killed Coccidioides immitis.

Converse, J. L. (U.S. Army Biological Laboratories, Fort Detrick, Frederick, Md.), G. A. Deauville, E. M. Snyder, J. G. Ray, and M. E. Seaquist. Control of tissue reactions in monkeys vaccinated with viable Coccidioides immitis by prevaccination with killed Coccidioides immities. J. Bacteriol. 90:783-788. 1965.-Control of undesirable tissue reactions resulting from the subcutaneous injection of 150 viable arthrospores of Coccidioides immitis (strain D-76) was obtained by four injections of formalin-killed arthrospores 14, 12, 8, and 4 weeks (total dose, 36 mg) before injection of the viable arthrospores. Only 6 and 12% of these vaccinated animals exhibited ulceration and lymphadenopathy, respectively, as compared with 100 and 83% of the animals receiving only the viable vaccine. Agar-gel immunodiffusion precipitin titers of approximately 1:64 were evident 3 months after vaccination in animals receiving both vaccines, as compared with 1:128 in those injected with the viable vaccine alone. The above data indicated that somatic reactions to injection of a viable vaccine could be eliminated by preinjection of a killed vaccine. However, 6 months after vaccination, respiratory challenge (7,500 strain Cash arthrospores) indicated that this treatment also impaired the protective effect of the viable vaccine. All animals receiving both vaccines developed mild pulmonary coccidioidomycosis, whereas only 50% of the animals receiving only the viable vaccine were infected. In addition, the group receiving both vaccines demonstrated a more rapid and higher postchallenge precipitin titer. All vaccinated animals (those receiving the killed, the viable, or a combination of the two vaccines) survived for 4 months after challenge, as compared with 88% mortality (50% within 14 days) in the nonvaccinated controls.     

Host-Parasite Relationship in a Susceptible and a Resistant Rose Cultivar Inoculated with Sphaerotheca pannosa.

Young leaves of two rose cultivars, one susceptible (rose Cardinal) and the other moderately resistant (rose Q. Elizabeth) to mildew infection, were either inoculated with Sphaerotheca pannosa or wounded with glass or metal needles. At different times after these treatments the presence of callose, lignin and phenolics in the infected or wounded cells was revealed by histochemical reactions. After either treatment no difference was found between the cultivars in the amount or earliness of deposition of callose or lignin, while phenolics were present in far larger amounts in the resistant cultivar. It is therefore suggested that one of the factors of rose resistance to powdery mildew might be the capacity to synthesize large amounts of phenolic compounds, also in view of the fact that the vacuoles of healthy epidermal cells are strongly electron opaque in rose Q. Elizabeth, while they are much more transparent in rose Cardinal.     

Host-Parasite Relationship in a Susceptible and a Resistant Rose Cultivar Inoculated with Sphaerotheca pannosa: I. Fungal Growth, Mechanical Barriers and Hypersensitive Reaction

Conidial germination and development of Sphaerotheca pannosa were studied on a susceptible and a resistant cultivar (rose Cardinal and rose Queen Elisabeth, respectively) in relation to the morphology of the leaf surface which was examined by scanning and transmission electron microscopy. Conidial germination was completed within 24 h in both cultivars and seemed to be higher in the resistant cultivar; fungal development, however, was stopped when the haustoria containing cells became necrotic. The only morphological difference between the leaves of the two cultivars is a thinner cuticle in rose Cardinal. Wax deposits on the leaf surface are similar; a layer of substances reacting to rhutenium red, most likely glycoproteins or protein-polysaccharide complexes, also are similar.     

丙型肝炎病毒多表位抗原在恒河猴中的免疫应答及保护性试验

利用ＨＣＶ抗原多表位来研制ＨＣＶ疫苗是目前的一个新方向。本研　究利用ＨＣＶ的ＨＣＶ的５个保守表位串联,并加入破伤风类毒素上的一个Ｔ细胞激活位点,设计成　一个ＨＣＶ多表位抗原基因ＰＣＸ,在大肠杆菌中表达,用此蛋白免疫恒河猴,诱导猴体产生了较　高的抗体水平,滴度达１∶１０００以上,在免疫后的６０周抗体滴度仍达１∶４０以上。同时,在免　疫后６周用人ＨＣＶ阳性血清攻击猴子,免疫ＰＣＸ的猴子出现一过性ＡＬＴ升高,在攻击后三周内用　ＲＴ－ＰＣＲ检测到猴血清内ＨＣＶ的ＲＮＡ阳性。结果表明,免疫多表位的ＰＣＸ蛋白可以诱导机体产生　高水平的免疫应答。     

丙型肝炎病毒多表位抗原在恒河猴中的免疫应答及保护性试验

利用HCV抗原多表位来研制HCV疫苗是目前的一个新方向.本研究利用HCV的HCV的5个保守表位串联,并加入破伤风类毒素上的一个T细胞激活位点,设计成一个HCV多表位抗原基因PCX,在大肠杆菌中表达,用此蛋白免疫恒河猴,诱导猴体产生了较高的抗体水平,滴度达11000以上,在免疫后的60周抗体滴度仍达140以上.同时,在免疫后6周用人HCV阳性血清攻击猴子,免疫PCX的猴子出现一过性ALT升高,在攻击后三周内用RT-PCR检测到猴血清内HCV的RNA阳性.结果表明,免疫多表位的PCX蛋白可以诱导机体产生高水平的免疫应答.     

Postconflict Behavior of Spectacled Leaf Monkeys (Trachypithecus obscurus). I. Reconciliation

Studies of postconflict behavior have focused on Old World primates, particularly on members of the cercopithecines and chimpanzees. We present data on patterns of reconciliation in two captive groups of spectacled leaf monkeys, members of the Colobinae. Reconciliation occurred at a high rate relative to that in other primate species and within the first minute following a conflict. Friendly postconflict contact was usually initiated by aggressors in one group, and by recipients in the other. But, there was no difference in postconflict initiative to contact in comparison with MCs. These two groups showed behavioral specificity in the context of postconflict reunions. Ventroventral embracing was a common, explicit (de Waal, 1993) form of reconciliation. The intensity of aggression and situations in which the victim responded aggressively had no effect on the likelihood of reconciliation occurring. The postconflict behavior of both groups lends further support to the relationship-quality hypothesis (Aureli et al., 1989). Kinship and rank distance and had no effect on reconciliation, though affiliation levels correlated positively with the tendency to reconcile. These results indicate that spectacled langurs are among the more tolerant of the species studied so far.     

Recall of Immunity in Mice Vaccinated with Salmonella enteritidis or Salmonella typhimurium

Mice were immunized with living Salmonella enteritidis or S. typhimurium and then were reinfected 8, 30, 60, and 150 days later with streptomycin-resistant strains of S. enteritidis, S. typhimurium, or a mixture of the two organisms. The level of resistance at the time of challenge and the rate at which resistance was recalled in late convalescence was determined by daily liver and spleen counts of the challenge population. An immediately effective specific antibacterial immunity was maintained only while the vaccinating strain could still be detected in the liver and spleen. Reinfection of vaccine-free mice with the homologous organism caused a rapid recall of antibacterial immunity (within 3 days), but the response to the heterologous organism was much slower (5 to 8 days). Simultaneous injection of both pathogens into the vaccinated mice resulted in liver and spleen growth curves which resembled those obtained when the two organisms were administered separately. The implications of these growth studies in the development of specific cellular immunity to Salmonella infections are discussed.     

Host-Parasite Relations In Initiation Of Infection: I. Occurrence Of Listeriosis In Arctic Mammals,With A Note On Its Possible Pathogenesis

A lemming colony maintained at Fort Churchill was examined for the possibility of the presence of L. monocytogenes in latent form, but the organism was not isolated. Following transfer of the lemmings from Churchill to Kingston, L. monocytogens was isolated. In speculation on the pathogenesis of Listerosis, the author suggests that an upset carbohydrate metabolism may be involved in the trigger mechanism. The isolation of L. monocytogenes from a seemingly ill Arctic fox caught at Fort Churchill is reported for the first time.     

Host-Parasite Relations in Loose Smut of Wheat: II. The Distribution of 14C-Labelled Assimilates

The effect of infection by Ustilago nuda on the distributionof ¹⁴C-assimilates in spring wheat plants at several stagesof growth was examined Only small differences were detectedbetween healthy and infected plants at the early stages, butthere were marked differences between the older plants The amountof assimilate exported by the fed leaf appeared to be dependenton the demand for assimilates in all plants, and was greatestduring a period of rapid growth of host or parasite, such asthe sporulation of the fungus in the infected ear The distributionof exported assimilates from the fed leaf of healthy plantsvaried with the position of the fed leaf, its stage of development,and the age of the plant, the pattern was very similar to thatfound in other plant diseases This pattern was altered by thepresence of the pathogen, which acted as an alternative siteof accumulation Totally different sites received ¹⁴C-labelledassimilates in infected plants, in some cases assimilates weretranslocated over unusually long distances, for example fromthe main shoot flag leaf to infected tiller ears. The differencein distribution correlated well with the differences in growthcaused by the pathogen. In addition, the ratio between the radioactivityin alcohol-insoluble and that in alcohol-soluble compounds wasaffected by the infection, in young infected plants more radioactivitywas present in the insoluble fraction and in older infectedplants in the soluble fraction     

Role of the Phagocyte in Host-Parasite Interactions XI. Relationship Between Stimulated Oxidative Metabolism and Hydrogen Peroxide Formation, and Intracellular Killing

The increased respiratory and hexose monophosphate activities noted in phagocytizing cells results in the formation of hydrogen peroxide. This is brought about by the oxidation of reduced nicotinamide adenine dinucleotide phosphate by its oxidase. Evidence is presented which indicates that this H(2)O(2) is involved in the intracellular killing of bacteria. When molecular oxygen was excluded from phagocytizing leukocytes by anaerobiosis, thus inhibiting H(2)O(2) formation, reduced intracellular killing was observed. In some cases the impairment of leukocytic bactericidal activity by anaerobiosis could be partially reversed by the addition of H(2)O(2). Exogenous catalase also could reduce intracellular killing. In addition, when leukocytic isolates were dialyzed so as to reduce endogenous H(2)O(2), the bactericidal activity of the leukocytes was significantly decreased under both aerobic and anaerobic conditions. These results occurred with both guinea pig and human leukocytes and with several test microorganisms.     

Host-Parasite Relations in Loose Smut of Wheat: III. The Utilization of 14C-Labelled Assimilates

Infection of wheat by Ustilago nuda caused an increased rateof export of radioactivity from the sixth leaf of infected plantsas compared with healthy plants. The ear acted as the most important‘sink’, in both infected and healthy plants. Erythntol,mannitol, and trehalose were present in the infected ears andnodes, but were not present in the healthy plants. Radioactivitywas incorporated into these compounds in the infected ear, andthis was reflected in a lower percentage in the insoluble fractionthan in the healthy ear.     

3D Analysis of the TCR/pMHCII Complex Formation in Monkeys Vaccinated with the First Peptide Inducing Sterilizing Immunity against Human Malaria

T-cell receptor gene rearrangements were studied in Aotus monkeys developing high antibody titers and sterilizing immunity against the Plasmodium falciparum malaria parasite upon vaccination with the modified synthetic peptide 24112, which was identified in the Merozoite Surface Protein 2 (MSP-2) and is known to bind to HLA-DRβ1*0403 molecules with high capacity. Spectratyping analysis showed a preferential usage of Vβ12 and Vβ6 TCR gene families in 67% of HLA-DRβ1*0403-like genotyped monkeys. Docking of peptide 24112 into the HLA-DRβ1*0401–HA peptide–HA1.7TCR complex containing the VDJ rearrangements identified in fully protected monkeys showed a different structural signature compared to nonprotected monkeys. These striking results show the exquisite specificity of the TCR/pMHCII complex formation needed for inducing sterilizing immunity and provide important hints for a logical and rational methodology to develop multiepitopic, minimal subunit-based synthetic vaccines against infectious diseases, among them malaria.