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Biomedical subjects

B Rubin

Publications and source records attributed to B Rubin.

At least 181 records · Page 10Linked to original sources
PubMed1976

Induction of specific anti-guinea pig T cell sera in rabbits.

In an attempt to increase the specificity of antisera raised in rabbits against strain 2 guinea pig thymocytes and brain, the rabbits were screened for titres of natural antibodies to thymocytes and other lymphocytes. Although unimmunized rabbits commonly had moderate titres of cytotoxic antibodies to guinea pig thymocytes, occasional animals had low titres to thymocytes and moderate titres to bone marrow cells. Intravenous immunization of this latter group of rabbits with thymocytes led to the production of high titred anti-thymocyte sera which were easily made specific for thymus-derived lymphocytes (T cells) by absorption with L2 C lymphoma, a bone marrow-derived lymphoma of strain 2 guinea pigs. Sera raised against guinea pig brain in complete Freund's adjuvant which had high titres of antibodies to both thymocytes and bone marrow cells could be made specific for T cells only with great difficulty. The cytotoxic activity of the anti-T cell serum could be absorbed by strain 2 thymocytes and brain homogenates, while high dilutions of this serum inhibited the formation of spontaneous rosettes between guinea pig lymphoid cells and normal rabbit erythrocytes.

Absorption↗
PubMed1976

Impact of Ig-anti-Ig column fractionation on T-lymphocyte functions.

C57Bl/6 anti-Pe15-immune spleen cells were fractionated on immunoglobulin (Ig)-anti-Ig antibody columns in medium containing EDTA or in EDTA-free medium. The antigen-specific cytotoxic potential of immune cells in vitro was only slightly enriched after passage through the columns in the absence of EDTA, whereas immune cells passed through the columns in the presence of EDTA displayed a cytotoxic potential enriched about three times compared with unfractionated cells; this is similar to the enrichment in theta-positive cells. The lack of increase of the cytotoxic potential of immune cells after passage through the columns in the absence of EDTA was shown to be due to the adsorption of subpopulations of cytotoxic T lymphocytes. These cytotoxic cells could be eluted with EDTA-containing medium, and the findings suggest that their adsorption may be mediated via the interaction between cell-bound Fc receptors and the column antigen-antibody complexes.

Animals↗
PubMed1976

Regulation of helper cell activity by specifically adsorbable T lymphocytes.

Mice immunized with soluble proteins such as human serum albumin (HSA) or ovalbumin (OA) develop in their spleens antigen-specific T and B lymphocytes. These populations of lymphocytes can be separated from each other by different means; e.g. treatment with anti-theta-antiserum and complement removes selectively T lymphocytes, whereas passage through glass bead columns coated with mouse immunoglobulin (Ig): anti-Ig complexes creates a relatively pure population of T lymphocytes. During the course of such separation studies it was observed that the helper capacity of HSA (or OA) immune mouse spleen cells after Ig:anti-Ig column passage frequently was higher than expected from the enrichment in theta-positive cells. In addition, after adsorption onto antigen coated Bio-Gel beads this effect was even more pronounced, i.e., and increase in the relative helper capacity of about 3 or 4 times compared with an increase in the content of theta-positive cells from about 30% to 40 to 50% after adsorption. The present results will demonstrate that the increased helper capacity was a specific phenomenon which was regulated by theta-positive cells. The regulatory cells specifically adsorbed onto antigen-coated Bio-Gel beads have not been successfully eluted by EDTA or excess-free antigen so far, and they were still adsorbed after pre-incubation with anti-Ig antibodies under conditions where specific B lymphocyte adsorption was almost prevented.

Adsorption↗
PubMed1975

H-2 private specificity of in vivo-sensitized lymphocytes studied by adsorption on fibroblast monolayers.

Spleen cells or thymocytes immune to one H-2 genotype are cytotoxic to allogeneic target cells of a third-party genotype, provided the target shares private specificities determined by either the H-2K or the H-2D locus of the H-2 complex with the H-2 genotype used for sensitization in vivo. The present results on elimination of cytotoxicity to specificities determined by one of the H-2 loci after adsorption of the immune lymphoid cells onto fibroblasts bearing this specificity suggest a state of diversity among effector lymphocytes reactive to the antigens determined by either the H-2K or the H-2D locus of the H-2 complex. Thymus cells activated in vivo were less specifically adsorbable than spleen cells of tumor-allografted mice.

Adsorption↗
PubMed1975

Biological significance of Fc receptor-bearing cells among activated T lymphocytes.

Lethally irradiated mice injected with syngeneic thymocytes and immunized with protein antigens develop specific helper T cells. If injected with semiallogeneic thymocytes, such mice generate H-2 antigen-specific cytotoxic T cells. Most spleen cells from these chimeric mice possess Fc receptors. The present results demonstrate that the development of Fc-receptor-bearing cells in thymocyte-injected irradiation chimeras seemingly is due to the physiological conditions in the mice rather than to the specific immunization. As a corollary, both helper T cells and cytotoxic T cells did not have Fc receptors, at least not in their effector state. Thus, Fc receptors on T cells would seem irrelevant to their immune function.

Animals↗
PubMed1975

The activity of T and B lymphocytes in immunity and tolerance to the lymphocytic choriomeningitis virus in mice.

Treatment with anti-theta serum and the Wigzell column technique for cell separation was employed to study the separate functions of the B and T lymphocytes in the late states of immunity to the LCM virus in mice. The cell preparations examined were mixtures of spleen and lymph node cells from immune mice. The results revealed that the anti-viral effect of such cells after transfer to virus carriers was unimpaired in T cell-enriched and B cell-deprived cell preparations. The anti-viral effect was also retained in cell preparations deprived so much of B cells that no antibody was produced in the virus carrier mice receiving transplants of these cells. The results strongly indicate that the anti-viral effect of late immune cells is not only T cell-dependent but that it is also mediated solely by T cells and, moreover, that antibodies have no or very little influence on the virus elimination. The observation that antibody production could be caused neither by column-passed cells nor by anti-theta serum-treated cells, but was obtained by mixtures of these cells, demonstrates that co-operation between T and B cells is crucial for the LCM antibody response. Accordingly, the convincing demonstration of the absence in the persistent virus carriers of cells which, in respect of antibody production, are able to co-operate either with column-passed or with anti-theta serum-treated immune cells, implies that such animals are extremely deficient as regards immune function of both B and T LCM-primed lymphocytes.

Animals↗
PubMed1975

Aneurysm of a polar renal artery.

A patient with a saccular aneurysm arising from the left superior polar renal artery is presented together with a review of two further reports from the literature. The importance of selective arteriography and the interpretation of the "naked calyx" sign in the diagnosis of supernumerary renal arteries has been emphasized. We feel that this is the only report of an aneurysm of a polar artery successfully treated by excision and end-to-end arterial anastomosis.

Adult↗
PubMed1974

Lymphocyte proliferation in vitro induced by hapten autologous protein conjugates. I. A study on the class of lymphocytes responding in vitro and on the nature and specificity of their receptors.

Immune lymph node cells from guinea pigs respond to soluble antigen in vitro by an increase in DNA synthesis. Optimal conditions for this proliferative response were studied in the present article. Under such conditions, immune cells showed increasing responses with increasing antigen concentration in vitro, the threshold dose of activation frequently being as low as 0.02 microg per culture. In contrast, normal lymph node cells (from FCA-stimulated animals) did only respond to antigen at very high doses (20 mg/culture), and immune cell dilution studies could be performed in normal cells without changing the kinetics of the antigen specific response of immune cells. Fractionation on anti-Ig columns indicated that purified, immune T lymphocytes were quite capable of proliferating in vitro upon antigen stimulation. However, our attempts to adsorb the proliferating cells onto chemically defined immunoadsorbants failed despite the fact that immune B cells (as measured by the rosette assay) were retained almost completely by such a procedure. Purified, immune T lymphocytes from guinea pigs immunized with different antigen concentrations in vivo and/or obtained at different times after immunization were tested for a differential sensitivity toward antigen-induced DNA synthesis in vitro. However, we were not able to demonstrate any regular increase in sensitivity to antigen in vitro, and if found, it seemed to be more dependent upon the number of antigen reactive cells in the population studied rather than upon differences in the average avidity of the receptors on the cells proliferating in vitro. The results in the present article are discussed in relation to current knowledge and hypotheses on T-lymphocyte receptors.

Animals↗
PubMed1974

Cytotoxic immune cells with specificity for defined soluble antigens. IV. Antibody as mediator of specific cytotoxicity.

Spleen cells from mice immunized against ovalbumin (OA) or dinitrophenylated mouse serum albumin (DM) were found to be specifically cytotoxic in vitro towards target cells (chicken red blood cells) coated with these antigens. Inhibition of specific cytotoxicity was observed when free soluble antigen was added to the incubation mixtures. DM-immune cell cytotoxicity could be specifically and completely inhibited by DNP-lysine and was thus shown to be hapten specific. Complete and specific inhibition was also observed for OA-immune cell cytotoxicity using OA as inhibitor, but compared with the inhibition curves obtained with DNP-lysine, the OA cytotoxicity inhibition curves were shifted by a factor of about one hundred towards lower molar inhibitor concentrations. Very similar results were observed when the serum antibodies of DM- and OA-immune animals were analyzed by passive hemagglutination inhibition. With increasing time after immunization, both cytotoxicity inhibition curves and agglutination inhibition curves, shifted to lower antigen or hapten concentrations. Specific cytotoxicity against antigen-coated target cells was induced in nonimmune spleen cells (a) by serum from immune animals, and (b) by supernatants from in vitro immune cell cultures. In both instances, the factor which induced antigen-specific cytotoxic activity could be absorbed on anti-mouse Ig columns, thus demonstrating its immunoglobulin nature. The ability of target cell bound antibodies to induce cytotoxicity in nonimmune spleen cells was restricted to the 7S antibody class.

Animals↗
PubMed1973

The immune response against hapten-autologous protein conjugates in the mouse.

Mice immunized with hapten-autologous serum albumin conjugates (DNP-mouse serum albumin) were shown to contain immune B and T cells with specificity for the conjugate. Fractionation on antigen-coated Sepharose beads showed that B cells could be subdivided in two major groups: those reacting against the haptenic group (DNP) and those reactive against the new antigenic determinants (NADs) introduced into the protein carrier by the hapten coupling. It was shown previously that humoral antibodies formed against hapten-mouse serum albumin conjugates also were directed against these two groups of antigenic determinants and that the immune response to the NADs does not follow the genetic rules of high or low response against the hapten used. All together these findings support the distinct nature of the NADs over the haptenic groups, as recognized both at the humoral and cellular level. Absorption of mouse cells immune to hapten-autologous serum albumin conjugates on antigen-coated Sepharose beads using a variety of incubation conditions resulted in no specific retention of T cells. Therefore we had to resort to specificity studies of T cells in relation to T cell function. Relatively pure immune T cell suspensions were obtained using fractionation on anti-immunoglobulin-coated columns. DNP-MSA-specific T cells were shown to be very specific for the DNP-MSA conjugate with only one exception: they cross-reacted with antigenic determinants on DNP-rat serum albumin. As DNP-specific help was excluded in the present transfer system (as shown by the inability of cells from DNP-skin-painted mice and DNP-heterologous protein conjugate specific T cells [anti-immunoglobulin column purified] to help a DNP-MSA response), these results demonstrate the NAD specificity of the DNP-MSA-reactive T cells. The cross-reactivity pattern of DNP-MSA-specific T cells was similar to that found for humoral anti-NAD antibodies produced against the same immunogen. Whether B and T cells are activated by the same antigenic determinants is discussed.

Animals↗