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B Bonavida

Publications and source records attributed to B Bonavida.

At least 181 records · Page 10Linked to original sources
PubMed1981

Expression of hybrid Ia molecules on the cell surface of reticulum cell sarcomas that are undetectable on host SJL/J lymphocytes.

SJL/J (H-2 (8)) lymphocytes, primed in vitro against primary, cultured, and transplantable syngeneic reticulum cell sarcomas (RCS) were found to recognize and bind to the tumor without subsequent cytolysis. Additional data showed that the recognition was also directed against Ia molecules of the H-2(d), but not H-2(k), haplotype. Normal spleen cells of DBA/2, B 10.D2, and B 10.OL mice were bound, whereas those of CBA, B 10.BR, B 10.A, B 10.GD, and D2.GD were not. Furthermore, the Ia molecules were in the form of a hybrid, because spleen cells from F(1) progeny of a B10.A and a B10.GD parent were recognized and bound as effectively as the RCS. Recognition was not restricted solely to the H-2(d) haplotype. Spleen cells from B10.S(9R) mice were also significantly bound. This result suggested that the RCS expresses a hybrid Ia molecule containing a beta-chain of the H-2(8) haplotype. Recognition of this hybrid Ia molecule by the host resulted in a cross- reactive recognition of H-2(d) specificities. Further analysis revealed that the RCS express on their cell surface an alpha-chain of the hybrid Ia molecule which is involved in host anti-tumor recognition. Preincubation of the RCS with monoclonal antibody directed against the Ia.7 specificity on the alpha-chain could block lymphocyte-to-tumor cell binding. The blocking activity could be removed by preabsorption of the antibody on the RCS, as well as normal Ia.7-bearing lymphocytes, but not on lymphocytes that do not express Ia.7, such as SJL/J. The data suggest that the hybrid Ia molecules expressed on the RCS, and recognized by tumor-primed syngeneic lymphocytes, are composed of both a syngeneic and an alien chain. The component alien to the SJL/J host is the Ia.7-bearing alpha-chain. Normal SJL/J cells synthesize but do not express the beta-chain. In the RCS, however, alien alpha-chain synthesis permits expression of the syngeneic beta-chain in the form of a hybrid Ia molecule.

Animals↗
PubMed1981

Detection and characterization of lymphocytes bearing receptors for peanut agglutinin by a specific rosetting technique.

Murine lymphocytes bearing receptors for peanut agglutinin (PNA) have been visualized using a specific rosetting technique. The lymphocytes were incubated with PNA and mixed with neuraminidase-treated sheep red blood cells. The percentage of the PNA rosetting lymphocytes found in the various organs studied was dependent upon the PNA concentration. In the spleen, the PNA rosetting lymphocytes were primarily T cells with low PNA concentration while both T and B lymphocytes were rosetted with high PNA concentration. In the fetal liver and thymus PNA rosetting lymphocytes were present in small amounts early in fetal life, increasing and reaching adult levels by late fetal life. The present study shows that the rosetting technique is more sensitive than previously described techniques for the detection of various lymphocyte subpopulation having receptors for PNA.

Animals↗
PubMed1980

Frequency determination of K cells by a single cell cytotoxic assay.

This report describes a highly reproducible single cell cytotoxic assay which can measure the frequency of K cells in human peripheral blood lymphocytes. This assay is based on the ability of FcR-bearing lymphocytes to bind to antibody sensitized target cells via their FcR. Approximately 30% of lymphocytes which bound antibody sensitized target cells via their FcR. Approximately 30% of lymphocytes which bound antibody sensitized P815 cells (P815-AB) were K cells. Cytolysis of the conjugated P815-AB fulfilled all the criteria for ADCC. Furthermore, an excellent correlation was observed between the frequency of K cells and % cytotoxicity as measured by the ADCC 51Cr-release assay. The mean frequency of human k cells in peripheral blood lymphocytes from 20 volunteers was measured to be 3.2% of the total lymphocyte populations.

Antibody Formation↗
PubMed1980

Inappropriate alloantigen-like specificities detected on reticulum cell sarcomas of SJL/J mice: characterization and biologic role.

SJL/J (H-2s) reticulum cell sarcomas (RCS) of different origins (spontaneous, transplantable, and cell lines) carry antigens that cross-react with BALB/c (H-2d) and C57BL/6 (H-2b) alloantigens in tests measuring cell-mediated cytotoxicity, antibody-dependent cytotoxicity, and immunofluorescence. These inappropriate antigens on RCS cells were not detected on normal SJL/J splenocytes. Immunochemical analysis of the inappropriate antigens by two-dimensional gel electrophoresis was performed with SJL/J anti-BALB/c and monospecific anti-H-2Dd sera. These sera precipitated 45,000 molecular weight molecules from BALB/c lymph node cells and from SJL/J in vivo and in vitro RCS tumor that appeared very similar. The sera also precipitated molecules from SJL/J lymph node cells that resemble the BALB/c and RCS molecules. Because of the highly immunogenic nature of RCS in vivo, we examined antigen-reactive cell opsonization (ARCO) as a possible mechanism of tumor enhancement. 125IUdR-labeled SJL/J anti-RCS lymphocyte (*ARC) were diverted to the liver (opsonized) when injected i.v. into syngeneic tumor-bearing mice. Furthermore, SJL/J anti-BALB/c *ARC were opsonized in mice with BALB/c positive spontaneous tumors but not in mice with H-2d negative tumors. Our results show that RCS tumors express inappropriate alloantigens (cryptic on normal cells) that are immunogenic in vivo. Specific antitumor ARC are opsonized in tumor bearers provoking ineffective immunity and survival of antigenic spontaneous RCS tumors.

Animals↗