Competitive interactions between species of fresh-water snails: I. Laboratory. IC. Comparative survival of Biomphalaria glabrata and B. Straminea kept out of water

Biomphalaria glabrata and B. straminea were submitted to an out-door laboratory experiment for testing their comparative ability to resist desiccation. Results have shown that B. straminea is significantly higher resistant than B. glabrata. After five months under such distressing condition the survival ratios were: B. glabrata 8.1 per cent and B. straminea 18.4 per cent.

Ectoparasitos de roedores da região urbana de Belo Horizonte, MG: II. Oscilações dos índices de infestação em Rattus norvegicus norvegicus

Os índices de infestação proporcionados pelo ácaro Echinolaelaps echidninus e Laelaps nuttalli, pelo piolho Polyplax spinulosa e pela pulga Xenopsylla cheopis, obtidos mensalmente no período de junho de 1980 a setembro de 1982, em Rattus norvegicus da região urbana de Belo Horizonte, Minas Gerais, Brasil, foram relacionados com períodos estacionais, sexo dos hospedeiros e áreas de captura. Acaros e insetos apresentaram comportamento diferente face a estas variáveis, já que apenas as pulgas e os piolhos exibiram associações significativas entre a infestação nos roedores e os períodos estacionais, ou entre a infestação e o sexo dos roedores, ou ainda uma variação da distribuição pelas áreas onde as capturas foram mais freqüentes. Enquanto as pulgas infestaram um maior número de roedores na estação chuvosa-quente (outubro a março), a infestação proporcionada pelo piolho foi mais intensa na estação seca-fria. Os fatores climáticos mais relacionados com a infestação nos hospedeiros foram, em ordem decrescente, a precipitação pluviométrica, a temperatura e a umidade relativa do ar. Tanto pulgas como piolhos apresentaram infestações preferenciais por roedores machos, sendo a proporcionada por X. cheopis, altamente significativa.

Ectoparasitos de roedores da região urbana de Belo Horizonte, MG: III. Indices pulicidianos, anoplurianos e acarianos em Rattus Norvegicus norvegicus

Indices pulicidianos, anoplurianos e acarianos, globais e específicos foram determinados para os ectoparasitos de Rattus norvegicus norvegicus capturados em zona urbana de Belo Horizonte, Minas Gerais, Brasil, no período de junho de 1980 a setembro de 1982. Tendo-se em vista os valores limites ou críticos atribuídos aos índices pulicidianos, sobretudo ao índice "cheopis" e propostos por diversos autores como medida complementar de vigilância epidemiológica para peste bubônica, a comunidade de Belo Horizonte poderia ter estado exposta a esta infecção, uma vez que os índices globais anuais de 0,3 a 2,4 e a pulga prevalente foi Xenopsylla cheopis (99,2%), com os maiores índices coincidindo com o final da estação seca-fria. Em duas ocasiões, a comunidade poderia ter permanecido altamente exposta à infecção, já que os índices-limites tolerados foram suplantados: 8,8 (outubro 1980) e 6,2 (setembro 1982). Sugere-se que medidas profiláticas como anti-ratização e desinsetização sejam eficazmente aplicadas ao final da estação seca-fria, ou anteriormente à chegada das chuvas, sendo sucedidas pela desratização. Informações sobre índices anoplurianos e acarianos são importantes para que se possa, no exclusivas de roedores

Comparative ELISA reagents for detection of hepatitis B surface antigen (HBsAg)

Conjugates of goat anti-HBs IgG and horseradish peroxidase (HRP) prepared by two different methods, one using NaIO4 and the other SPDP, were compared. Anti-HBs antibodies obtained from goat, rabbit and guinea-pig were tested as capture serum. The ELISA showed a sensitivity similar to RIA and a level of antigen captation ranging from 4.37 to 8.75 nanograms/ml was obtained when rabbit or guinea-pig captures were used combined with both NaIO4 or SPDP conjugates.

A novel anti-CD19 monoclonal antibody (GBR 401) with high killing activity against B cell malignancies.

BACKGROUND: CD19 is a B cell lineage specific surface receptor whose broad expression, from pro-B cells to early plasma cells, makes it an attractive target for the immunotherapy of B cell malignancies. In this study we present the generation of a novel humanized anti-CD19 monoclonal antibody (mAb), GBR 401, and investigate its therapeutic potential on human B cell malignancies. METHODS: GBR 401 was partially defucosylated in order to enhance its cytotoxic function. We analyzed the in vitro depleting effects of GBR 401 against B cell lines and primary malignant B cells from patients in the presence or in absence of purified NK cells isolated from healthy donors. In vivo, the antibody dependent cellular cytotoxicity (ADCC) efficacy of GBR 401 was assessed in a B cell depletion model consisting of SCID mice injected with healthy human donor PBMC, and a malignant B cell depletion model where SCID mice are xenografted with both primary human B-CLL tumors and heterologous human NK cells. Furthermore, the anti-tumor activity of GBR 401 was also evaluated in a xenochimeric mouse model of human Burkitt lymphoma using mice xenografted intravenously with Raji cells. Pharmacological inhibition tests were used to characterize the mechanism of the cell death induced by GBR 401. RESULTS: GBR 401 exerts a potent in vitro and in vivo cytotoxic activity against primary samples from patients representing various B-cell malignancies. GBR 401 elicits a markedly higher level of ADCC on primary malignant B cells when compared to fucosylated similar mAb and to Rituximab, the current anti-CD20 mAb standard immunotherapeutic treatment for B cell malignancies, showing killing at 500 times lower concentrations. Of interest, GBR 401 also exhibits a potent direct killing effect in different malignant B cell lines that involves homotypic aggregation mediated by actin relocalization. CONCLUSION: These results contribute to consolidate clinical interest in developing GBR 401 for treatment of hematopoietic B cell malignancies, particularly for patients refractory to anti-CD20 mAb therapies.

B and T lymphocyte attenuator regulates CD8+ T cell-intrinsic homeostasis and memory cell generation.

B and T lymphocyte attenuator (BTLA) is a negative regulator of T cell activation, but its function in vivo is not well characterized. Here we show that mice deficient in full-length BTLA or its ligand, herpesvirus entry mediator, had increased number of memory CD8(+) T cells. The memory CD8(+) T cell phenotype resulted from a T cell-intrinsic perturbation of the CD8(+) T cell pool. Naive BTLA-deficient CD8(+) T cells were more efficient than wild-type cells at generating memory in a competitive antigen-specific system. This effect was independent of the initial expansion of the responding antigen-specific T cell population. In addition, BTLA negatively regulated antigen-independent homeostatic expansion of CD4(+) and CD8(+) T cells. These results emphasize two central functions of BTLA in limiting T cell activity in vivo.

Restriction in the repertoire of detectable autoantibodies in polyclonal B cell activations and the mimicry of autoantigens by idiotopes

Despite the existence of erythrocyte-autoreactive B cells in normal animals, erythrocyte-autoantibodies could not be detected during polyclonal B-cell activation (PBA) both in patients with visceral leishmaniasis and in bacterial lipopolysacharide (LPS) - injected mice. The failure to detect these autoantibodies in mice with PBA di not seem to be due to suppressor-cell activity, since (1) transfer of spleen cells from LPS-treated mice to naive recipients did not affect the erythrocyte-autoantibody response elicited by subsequent injections of rat erythrocytes and (2) low doses of X-radiation did no lead to erythrocyte-autoantibody detection in LPS-treated mice. The possibility that the detection of erytrocyte-autoantibodies could be affected by autoantibodies with idiotopes mimicring erythrocyte epitopes, the synthesis of which would also be triggerred in PBA, is discussed. Indirect evidence for the existence in normal animal of an expanded lymphocyte population with DNP-binding. Ia-mimicring antigen receptors is presented.

Notch signaling in T- and B-cell development.

The Notch family of evolutionarily conserved proteins regulates a broad spectrum of cell-fate decisions and differentiation processes during fetal and post-natal development. The best characterized role of Notch signaling during mammalian hematopoiesis and lymphopoiesis is the essential function of the Notch1 receptor in T-cell lineage commitment. More recent studies have addressed the roles of other Notch receptors and ligands, as well as their downstream targets, revealing additional novel functions of Notch signaling in intra-thymic T-cell development, B-cell development and peripheral T-cell function.

Competitive displacement of Biomphalaria glabrata by B. straminea

Data on the interaction between populations of closely related species of Biomphalaria, B. glabrata and B. straminea, are presented in the current paper. Laboratory and field observations and experiments have shown that B. straminea has competitive advantages over B. glabrata.

Resistência de Biomphalaria peregrina de Santa Rita do Sapucaí, Minas Gerais, a infecção com três cepas de Schistosoma mansoni

Descendentes do planorbídeo Biomphalaria peregrina, coletados em Santa Rita do Sapucaí, Minas Gerais, Brasil, foram expostos a miracídios de três cepas de Schistosoma mansoni: "LE" de Belo Horizonte, MG; "SJ" de São José dos Campos, SP e "AL" do Estado de Alagoas. Dentre 300 exemplares expostos, nenhum se infectou com as três cepas do trematódeo. Por outro lado, 300 exemplares de B. glabrata, dos grupos de controle, apresentaram taxas de infecção de 61,1 a 95,3% com as três cepas do trematódeo. As taxas de mortalidade de B. peregrina e de B. glabrata foram de 20,0 e de 28,0%, respectivamente.

Prevalence of nits and lice in sampls of cut hair from floors of barbershop and beauty parlors in Belo Horizonte, Minas Gerais state, Brazil

A louse survey based on samples of cut hair collected from floors of barbershops and beauty parlors was conducted in Belo Horizonte, Minas Gerais State, Brazil, from October 1984 to April 1985, as an alternative way to determine the prevalence of pediculosis capitis in the population. Of 475 samples examined for nits, nymphs, or adults of Pediculus capitis, 140 were infested (29.5%). A total of 58 lice and 3.553 nits were found in 33.632.9 g of hair collected, giving a ratio of 0.10 nit/g. Almost 29% of the nits were viable and capable of being transmitted after hatching. There was significant difference among the infestation rates by socioeconomic levels, and samples from barbershops with male customers were the most infested. based upon the number of haircuts in each sample, we estimated that 5 or 6% of the population might be infested by this species.

B cell dependent T lymphocyte responses in leishmaniasis

The activation of B cell dependent T cells during Leishmania infection cannot be considered a trivial event, because their removal profoundly alters the course and outcome of infection within genetically susceptible and resistant mouse strains. The demonstration that idiotype recognizing T cells also appear within human populations sensitized to leishmanial antigens as a result of asymptomatic or subclinical infections supports a role for these cells in immunity. These cells are not demonstrable in patients with active visceral disease, so that their role in promoting specific unresponsiveness has not been extended to humans. Whether B cell dependent, idiotype specific T cells represent a functionally distinct T lymphocyte subset with unique regulatory activities remains to be determined.