Immune response to BCG-Moreau (Rio de Janeiro) strain. Spectrum of delayed hypersensitivity in genetically defined mice

Abstract Generation of delayed hypersensitivity (DTH) in genetically defined mice immunized with Mycobacterium bovis BCG of the Moreau (Rio de Janeiro) strain was studied. This vaccine strain has been reported as the most virulent and able to induce strong tuberculin sensitivity. Mice were selected by the expression of Bcg gene trait, by responsiveness to mycobacterial antigens and H2 haplotype. DTH was evaluated by the ear-swelling test of mice immunized subcutaneously with live BCG at doses ranging from 1 μg to 1000 μg. A survey of inbred strains of mice showed H2b and H2q mice as high responders, H2d as an intermediate responder, H2k as a low responder and H2a as a non-responder. Study of H2-congenic pairs of high and non-responder strains showed significant DTH in all mice independently of the genetic background and H2 haplotype. A mouse strain expressing Bcg (r) trait displayed DTH superior to a Bcg (s) strain. Comparison of DTH response of strains expressing Bcg (r) or (s) trait showed no relationship between the Bcg locus and DTH to mycobacteria. These data suggest DTH is under polygenic control including the major histocompatibility complex but excluding the Bcg locus.     

Vectorial competence of Aedes aegypti (Linnaeus 1762) Rio de Janeiro strain, to Dirofilaria immitis (Leidy 1856)

Dirofilaria immitis (Leidy 1856), a nematode parasite, is the etiologic agent of canine heartworm disease and mosquitoes are essential intermediate hosts. Mosquito susceptibility to the worms differ with species, strains and also among individuals of the same strain. To evaluate the degree of susceptibility of Rio de Janeiro laboratory raised strain of Aedes aegypti, we fed mosquitoes on canine blood with different densities of microfilariae (mf). There was no significant difference in the rate of development among the three different densities of mf. Infective larvae were found in the head and proboscis of all mosquitoes provided bloodmeals with different densities of mf after the 11th day post-infection. The infection rate of mosquitoes after ingestion of blood containing 3,000 mf/ml, 5,000 mf/ml and 7,000 mf/ml were 55.3%, 66.7% and 100%, respectively. The vector efficiency indices ranged from 1.6 to 9.3. The finding of L3 stage larvae, high infection rates and vector efficiency indices suggest that Ae. aegypti, Rio de Janeiro laboratory strain, is a potential vector of D. immitis, although of low efficiency.     

Prevalence of paracoccidioidomycosis in hospitalized adults in Rio de Janeiro (RJ) Brazil

Double immunodiffusion were used as screening test for the diagnosis of paracoccidioidomycosis. Five hundred hospitalized adults from general (150 patients — group I) and from a specialized chest disease hospital (350 patients — group II), were tested. All of them were without definitive etiological diagnosis and clinical specimens were obtained from the patients with positive serology. Testing sera obtained from 150 patients of the group I, fifty six cases of paracoccidioidomycosis were diagnosed. Specimens for mycological examination were subsequently obtained from 50 of these patients; P. brasiliensis could be recovered in 49 (98%). Fundamental importance was the finding of 17 (4.8%) cases of paracoccidioidomycosis among the 350 patients referred from a chest disease hospital (group II). Serological evidence of paracoccidioidomycosis found in 73 (14.6%) of the 500 screened patients, indicates a relatively high prevalence of this mycosis in adults patients admitted to several hospitals in RJ. These data probably do not reflect the real prevalence of paracoccidioidomycosis in RJ and should be considered as a gross underestimation. Thus, attention should also be paid to juvenile forms and DID could be of a great value in screening these cases too.This work forms part of the thesis A importância das técnicas de imunoprecipitação na triagem e diagnóstico da paracoccidioidomicose, histoplasmose e aspergilose. Estudo em população hospitalar do RJ. M. Phil. on Parasite Biology, Instituto Oswaldo Cruz, RJ — 1984.     

Primary antibody and delayed type hypersensitivity response of mice to ovalbumin

The control of the ability to respond to three doses of ovalbumin has been studied in an attempt to find the minimum dose of antigen necessary for activation of primary antibody response and delayed type hypersensitivity response. In seven of the ten mouse strains studied, concordance of the minimum dose needed to elicit the two responses was observed. Discordance is found in the other strains, suggesting that the ability to respond to ovalbumin is independently controlled in several cells. The antibody and delayed type hypersensitivity responses to ovalbumin are controlled by at least two genes, one localized in the major histocompatibility complex.     

Dengue virus type 3 in Rio de Janeiro, Brazil.

Dengue virus type 3 was isolated for the first time in the country as an indigenous case from a 40 year-old woman presenting signs and symptoms of a classical dengue fever in the municipality of Nova Igua?u, State of Rio de Janeiro. This serotype has been associated with dengue haemorrhagic epidemics and the information could be used to implement appropriate prevention and control measures. Virological surveillance was essential in order to detected this new serotype.     

Some aspects of lead pollution in Rio de Janeiro

Lead concentrations in drinking water and air have been measured.Houses with lead inlet pipes had between 30 and 1000 μg l⁻¹, with a mean of about 100 μg l⁻¹. Houses without lead pipes had no detectable lead (< 10 μg l⁻¹).Average annual concentrations of airborne lead at six different collecting sites varied from 0·3 to 1·7 μg m⁻³. Measurements at street level, however, showed much higher values, from 1 to 100 μg m⁻³. The implications of these results are discussed briefly.     

Ecological segregation of woodcreepers (Dendrocolaptidae) in the state of Rio de Janeiro, Brasil

The 48 Neotropical woodcreepers feed in a variety of ways, such as among Mauritia palm fronds (e.g., Cinnamon-throated Woodcreeper Dendrexetastes rufigula ), as obligate ant followers (e.g., White-chinned Woodcreeper Dendrocincla merula ) or by probing the ground (e.g., Scimitar-billed Woodcreeper Drymornis bridgesii). However the typical foraging method of a member of this group, which lacks obvious ecological counterparts in the rainforests of South-East Asia and Africa (Pearson 1977, G. H. Orians, pers. comm.), is to glean bark-living arthropods while ascending a tree trunk, rather in the manner of a Certhia treecreeper. The bird then crosses, often by a descending glide, to begin the ascent of another trunk. Determinants of a species' preferred feeding station are thus likely to include height Above ground and trunk diameter, both of which are readily measured, and bark characteristics. The woodcreepers are therefore potentially admirable (and hitherto unused) subjects for quantitative studies of niche overlap. I report here on the overlap of the woodcreepers of the rainforests of South-East Brasil.     

Nonantibody-mediated suppression of delayed hypersensitivity to human gamma-globulin in mice.

Development of delayed hypersensitivity (DHS) to human γ-globulin (HIgG) in mice was documented by histological analysis, by the kinetics of footpad swelling in animals exhibiting humoral or delayed responses, and by the failure of sera to transfer delayed reactions to normal, syngeneic recipients. Since cyclophosphamide (CY) treatment resulted in diminished humoral and augmented delayed reactions, we used this as a tool to explore the nature of the regulatory mechanisms which affect expression of this type of cell-mediated immunity. In order to evaluate the effect which the presence or absence of antigen-specific cells might exert on expression of DHS, we subjected mice to experimental regimes which would result in lymphocyte proliferation or depletion, respectively (see Bachvaroff, R., and Rapaport, F. T., Cell. Immunol. 15, 336, 1975). Cell proliferation was induced by injection of 80 μg of aqueous antigen on Day ?4; this was followed by sensitization with HIgG-CFA (Freund's adjuvant) on Day 0, and footpad challenge on Day 13. These mice exhibited strong humoral reactivity; three of six died of anaphylaxis following footpad challenge, and the remaining three showed a diminished delayed response. Similarly treated mice that, in addition, received 6 mg of CY 3 days after injection of aqueous antigen and, therefore, would have antigen-specific cells present showed greatly diminished humoral reactivity, due to B-cell depletion. However, they also exhibited a marked diminution in delayed responsiveness. The data clearly demonstrate that a nonantibody-mediated, possibly cell-directed, regulatory influence is exerted on DHS where cell proliferation has occurred. We next examined the impact which the depletion of proliferating cells would exert on the expression of DHS. Cell depletion was attempted by giving one injection of aqueous antigen (Day 0) early in a regime of chronic CY administration (Days ?1 through +3) ; antigen-induced proliferating cells would be susceptible to CY and, therefore, depleted under these conditions. The results show that mice receiving both aqueous antigen and CY have depressed humoral and markedly diminished delayed reactivity compared to animals that were injected with CY alone. Thus, the augmenting effect which CY exerts on DHS is abrogated by stimulation with aqueous antigen. One interpretation is that CY removes a regulatory cell population in the normal animal, thereby allowing enhanced expression of delayed responsiveness. Clearly, regulatory function cannot be attributed solely to bumoral antibody production.     

The invasion of urban forest by dengue vectors in Rio de Janeiro.

The invasion of a secondary forest within the city of Rio de Janeiro by Aedes aegypti and Ae. albopictus was evaluated from July 1997 to June 1998 through collections of immature stages in ovitraps set at 1 m, 10 m, 100 m, 500 m, and 1,000 m into the forest from houses on the periphery. Both mosquito species were much more abundant close to houses (1-10 m). Aedes aegypti was not collected beyond 100 m, while Ae. albopictus was the most abundant species overall and in ovitraps at all distances from houses. Abundances of Ae. albopictus were significantly correlated with time-lagged rainfall and with abundances of Ae. aegypti. Co-occurrences of Ae. albopictus in traps with Ae. aegypti and Limatus durhami, but not with Culex dolosus, were more likely close to houses. The results suggest that the urban forest is a refuge for both Aedes species, but especially for Ae. albopictus, whose abundance both near houses and in the forest raises concern that this invader may transmit arboviruses to humans that are presently restricted to the sylvan environment.     

Chironomids on Leaves of Typha domingensis in a Lagoon of Rio de Janeiro State (Brazil)

In Imboacica Lagoon, near Rio de Janeiro, chironomid larvae of the genera Endochironomus Kieffer, Goeldichironomus Fittkau, Polypedilum Kieffer and Monopelopia Fittkau occurred on senescent, submerged leaves of Typha domingensis.     

Yeasts associated with Drosophila in tropical forests of Rio de Janeiro, Brazil.

The distribution and diversity of yeast species vectored by and from the crop of eight species groups of Drosophila is described for two rain forest sites and an urban wooded area in Rio de Janeiro, Brazil. The typical forest Drosophila groups guarani, tripunctata, and willistoni showed a higher diversity of yeasts than the cosmopolitan melanogaster species group, suggesting different strategies of utilization of substrates. Apiculate yeasts, including Kloeckera apis, Kloeckera javanica, and Kloeckera japonica, were the prevalent species. Geotrichum spp. and Candida citea were also frequent isolates in the forest sites. Similarities between the yeasts from the external surfaces and crops of Drosophila suggested that the feeding substrates were the main source of the yeasts vectored by these flies. Most of the yeasts were strong fermenters and assimilated few compounds, usually sucrose, cellobiose, and glycerol. This indicated a preference of the flies for food sources such as fruits. Some yeasts were primarily isolated from one group of Drosophila; for example, Kloeckera javanica from the melanogaster group, Debaryomyces vanrijiae var. yarrowii from the tripunctata group, and Kluyveromyces delphensis from the willistoni group. These associations and differences in the yeast communities among the fly groups suggested a differentiation of diets and specialization of the yeast-Drosophila association in the tropical forests.     

Delayed-type hypersensitivity response in mice to Pneumocystis carinii.

Resistance to Pneumocystis carinii infection appears to be mediated by T lymphocytes but the mechanism and subsets of T cells involved are poorly understood. We used the BALB/c mouse model to study the delayed-type hypersensitivity (DTH) response to rat P. carinii. Mice were sensitized to P. carinii for seven days and then challenged with P. carinii antigens in the right rear footpads and normal rat lung antigens in the left rear footpads. A typical DTH response was observed in the right footpads as evidenced by significant swelling and substantial mononuclear cell infiltration at 24-h post-challenge. The DTH response could be transferred to naive syngeneic mice by adoptively transferring spleen cells from P. carinii-sensitized mice. In addition, by using anti-thy-1, anti-mouse Ig, anti-L3T4 and anti-Lyt-2.2 monoclonal antibodies in in vitro cytolysis experiments, we were able to demonstrate that the DTH response was dependent upon T lymphocytes. The response appeared to require cooperation between both L3T4+ and Lyt 2+ subsets of T lymphocytes.     

Parity and ovarian development of Aedes aegypti and Ae. albopictus (Diptera: Culicidae) in metropolitan Rio de Janeiro.

Vector blood-feeding frequency, parity, and ovarian development are important factors that can influence pathogen transmission. Parity rates of the dengue vectors Aedes aegypti and Ae. albopictus were determined from females collected from August 2002 to July 2004 in metropolitan Rio de Janeiro. A high frequency of parous Ae. aegypti (92.9%, n = 550) and Ae. albopictus (99.1%, n = 320) females suggested high survivorship of both species. A total of 69% of wild-caught Ae. aegypti females had blood in the midgut compared to 19% of Ae. albopictus. For Ae. aegypti, red-colored midgut contents were associated with ovaries in early stages of development, and brown-colored midguts were associated with ovaries in late stages of maturation. Ovaries of Ae. aegypti females without blood in the midgut were most frequently in stages I and V of Christophers.     

Distribution of Micropogonias furnieri (Pisces: Sciaenidae) in Sepetiba Bay,Rio de Janeiro,Brazil

Distribution of Micropogonias furnieri in the Sepetiba Bay, an ecosystem highly important as rearing ground for this species that represents 5.8% of the numerical catches by otter trawling, was analyzed based in monthly and bi-monthly samplings from two programmes (beach seines = continental margin; and otter trawl = inside of the Bay), over three annual cycles, between 1993 and 1997. Spatial comparisons were assessed by dividing the Bay in two zones for the beach seines (inner and outer Bay) and three zones for the otter trawl (inner, central and outer Bay), following depth, salinity and transparency gradient, as well as for the influence of the sea. Beach seines (30 m extension, a 10 m length x 2.5 m of height x 7 mm mesh) and otter trawls were used. Trawls covered 1.5 km and the boat (net mouth 8 m, mesh size 12 mm between opposites knots in the cod). Temperature (degree C) and salinity (p.s.u.) were taken in each sampling; depth (m) and transparency (m) were measured during the trawl. Fish from beach seine were basically young-of-the-year; in the trawl they were individuals of larger size with total length varying from 70 mm to 300 mm. Spatially, highest CPUEs were found for the continental margin in the inner Bay, and for the inside Bay, in the inner and central zones. Highly significant correlations were detected among M. furnieri abundance and low salinity, transparency and depth in the inner Bay, with no defined pattern for the continental margin. Temporally, differences in fish abundance were shown only for the second annual cycle (1996) for the continental margin, with peaks in September/October.     

Yeast communities associated with sugarcane in Campos, Rio de Janeiro, Brazil.

Yeast communities associated with sugarcane leaves, stems and rhizosphere during different phases of plant development were studied near Campos, in Rio de Janeiro, Brazil. Atmospheric temperature, soil granulometry and pH, and sugar cane juice degree Brix and pH were determined. Yeast communities associated with sugarcane were obtained after cellular extraction by shaking, blending and shaking plus sonication, and cultured on Yeast Nitrogen Base Agar plus glucose (0.5%) and Yeast Extract-Malt Extract Agar. No significant differences in yeast counts were found among the cellular extraction treatments and culture media. 230 yeast cultures were identified according to standard methods, and distinct yeast communities were found for each substrate studied. The prevalent species isolated from sugarcane were Cryptococcus laurentii, Cryptococcus albidus, Rhodotorula mucilaginosa and Debaryomyces hansenii.