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Biomedical subjects

O L Oliveira

Publications and source records attributed to O L Oliveira.

At least 19 recordsLinked to original sources
PubMed1986

Autoimmunity to Thy-1.

Conditions are described for the induction of autoimmunity to Thy-1 and a large panel of monoclonal CBA and AKR autoantibodies has been characterized. These reveal a hitherto unrecognized complexity at the Thy-1 locus and evidence for intragenic control. Epitopes recognized by the autoantibodies differed in species and tissue distribution from alloantigenic determinants but their specificity was confirmed by transfection studies with the cloned Thy-1b gene. The quantitative and qualitative differences in epitope expression between Thy-1a and Thy-1b alleles were inherited as single Mendelian traits and in the absence of recombinants, suggesting translational control.

Animals↗
PubMed1985

A new thymocyte membrane differentiation antigen for mouse and rat.

A new thymocyte membrane-brain antigenic system is defined for the mouse and rat. Monoclonal antibody NIM-M129 recognizes a membrane antigen that has a similar size to Thy-1 (20-23 kd) but entirely different tissue distribution. It is absent from cortisone-resistant thymocytes, murine peripheral T cells, T-cell blasts, and T-cell lymphomas, or rat bone marrow. However, the determinant exhibits a quantitative difference in expression on thymocytes of Thy-1a (low) and Thy-1b (high) mice, with intermediate values for their F1 progeny. Backcross and F2 segregation tests between CBA and CBA-Thy-1a congenic lines established firm genetic linkage between Thy-1 and the level of epitope expression on the thymocyte cell surface.

Animals↗
PubMed1980

Humoral suppression in Trypanosoma cruzi infection in relation to the timing of antigen presentation.

(CBA x C57 B1/10)F1 mice infected intraperitoneally with 100 parasites of Trypanosoma cruzi strain Y developed an infection with acute and chronic phases. Humoral suppression to sheep red blood cells was evident in both phases but enhancement of the response was achieved only at the beginning of the infection. A mitogen secreted by the parasite could explain both phenomenons.

Acute Disease↗
PubMed1980

A fraction (FAd) from Trypanosoma cruzi epimastigotes depresses the immune response in mice.

The primary immune response to SRBC in BALB/c mice was depressed when they were injected with a fraction (FAd) obtained from Trypanosoma cruzi epimastigotes grown in LIT medium. Plaque-forming cell (PFC) number was 50% less than controls when FAd was injected i.v. 15 min before antigen in doses ranging from 70 microgram up to 400 microgram of protein. Similar depression was observed when 100 microgram FAd was injected up to 6 h before antigen. There was no shift in the peak response to SRBC, neither was depression detected, when a total of 100 microgram FAd protein was given in 20 microgram amounts twice a day before immunization. Mice injected with FAd fraction only showed no increase in background PFC. Both secondary IgM and secondary IgG PFC were depressed when FAd was given before the boosting injection. However, only IgG PFC were depressed when FAd was injected before the priming dose. The delayed-type hypersensitivity reaction to DNFB was depressed when animals were injected either during the 3 days after sensitization or with a single dose of 100 microgram of protein of FAd on day of challenge. Bone marrow colony-forming units in spleens of mice injected with FAd were depressed and nodules in the treated animals were smaller than in controls. We conclude that FAd affects humoral and cell-mediated immune responses by interfering with cell division at some stage of the cell cycle.

Animals↗
PubMedDate not supplied

Restricted expression of LW antigen on subsets of human B and T lymphocytes.

NIM-M8 is a monoclonal IgM antibody, specific for the LWab antigen as shown by its reaction with red cells of all donors except those lacking LWa, LWb and LWab. Indirect immunofluorescent staining and cell sorter analyses have shown that LWab is present on a subpopulation of human lymphocytes. Cell fractionation studies indicate that subsets of both B and T cells express LWab and it may, therefore, provide a further marker for heterogeneity in these lymphocyte populations.

Antibodies, Monoclonal↗