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J Sprent

Publications and source records attributed to J Sprent.

At least 235 records · Page 13Linked to original sources
PubMed1972

A receptor for antibody on B lymphocytes. I. Method of detection and functional significance.

Evidence is presented for the existence on all B lymphocytes, but not on T lymphocytes, of a membrane-associated receptor for antibody. The receptor was detected by a radioautographic technique in which lymphoid cells were incubated with antibody followed by the corresponding radioiodinated antigen. The ease with which antibody eluted during washing indicated that the bond between antibody and cell was weak. The formation of an antibody-antigen complex on the cell surface, however, stabilized the bond and permitted accurate quantitation of cells with adherent antibody. The ability of several combinations of antibody and antigen to adhere to the cells demonstrated the nonspecificity of the phenomenon and emphasized the need for care in interpretation of antigen-binding studies particularly when immune cells are being used. The identity of antibody-binding lymphocytes was established by two different approaches. In the first, mouse lymphocyte populations greatly enriched for either T cells or B cells were examined. Their T cell content was assessed by means of well-established markers such as the theta C3H isoantigen. When this was compared with the number of antibody-binding cells, an inverse relationship was obtained in each instance; thus almost all thoracic duct cells from athymic mice labeled with an immune complex although none were theta positive. The striking reduction in antibody-binding cells observed in bursectomized chickens provided a second and independent line of evidence suggesting that B cells, not T cells, bind antibody. The ability of B cells from primed animals to bind antibody in vivo made it important to test whether this phenomenon was related to the carriage of immunological memory. No correlation was, however, found between membrane-bound antibody and memory. It was proposed that the existence of a receptor of this kind may provide a rational explanation for antibody-dependent killing of target cells and may prove of importance in antigen concentration particularly during the secondary response.

Animals↗
PubMed1972

Quantitative features of a sandwich radioimmunolabeling technique for lymphocyte surface receptors.

The present study was designed to devise and characterize an indirect or sandwich radioimmunolabeling technique for the study of lymphocyte surface receptors of immunoglobulin nature. Mouse lymphocytes from various sources were treated by the method of Shortman et al. to remove debris and damaged cells. This was an important preliminary step, as without it, little meaning could be attached to bulk scintillation counting of labeled cell suspensions, in view of the marked tendency of dead or damaged cells to adsorb protein nonspecifically. Next, cells were reacted at 0 degrees C for 30 min with graded dilutions of unlabeled rabbit antisera against defined mouse Ig chains. After washing, the cells were reacted with a sheep anti-rabbit globulin reagent labeled with (125)I, again at graded concentrations. After further washing, lymphocyte labeling was quantitated by both bulk scintillation counting and radioautography. Conditions were defined in which nonthymus-derived cells (B cells) but not thymus-derived cells (T cells) could be labeled. Most B cells displayed kappa- and micro-chains on their surface, but some also displayed alpha- and gamma(2)-chains, though in smaller amounts. When the concentration of both the first and the second reagents were raised considerably, conditions were defined under which virtually all T cells could be labeled by polyvalent antiglobulin sera, anti-kappa sera, or, with more difficulty, by anti-micro sera. A large series of control experiments confirmed the serologic specificity of this labeling. It was shown that under equivalent conditions, B cells bind 100-400 times more antiglobulin than do T cells. The theoretical implications of the results are briefly discussed. It is argued that the sandwich approach offers certain technical advantages over direct labeling procedures for further analyses of T cell receptors and for studies of receptor metabolism.

Animals↗
PubMed1972

Antigen-binding specificity of isolated cell-surface immunoglobulin from thymus cells activated to histocompatibility antigens.

Lactoperoxidase-catalyzed radioiodination of cell-surface proteins was used in the isolation of cell-surface immunoglobulin from thymus-derived thoracic duct lymphocytes activated to histocompatibility-2 antigens. Immunoglobulin was identified by specific precipitation with antiserum to mouse immunoglobulin. Polyacrylamide gel electrophoresis of reduced and alkylated precipitates showed that the immunoglobulin molecules possessed mu-type heavy chains and light chains. Cell-surface immunoglobulin isolated from thymus-derived cells activated to histocompatibility-2 antigens possessed binding specificity for the activating antigens.

Alkylation↗
PubMed1971

Cell-to-cell interaction in the immune response. VII. Requirement for differentiation of thymus-derived cells.

Experiments were designed to test the possibility that thymus-derived (T) cells cooperate with nonthymus derived (B) cells in antibody responses by acting as passive carriers of antigen. Thoracic duct lymphocytes (TDL) from fowl gammaG-tolerant mice were incubated in vitro with fowl anti-mouse lymphocyte globulin (FALG), which was shown not to be immunosuppressive in mice. On transfer into adult thymectomized, irradiated, and marrow protected (TxBM) hosts together with a control antigen, horse RBC, a response to horse RBC but not to fowl gammaG was obtained. By contrast, TxBM recipients of nontolerant, FALG-coated TDL responded to both antigens and the antibody-forming cells were shown to be derived from the host, not from the injected TDL. These findings suggested that, under the conditions of the experiment, triggering of unprimed B cells in the spleens of TxBM hosts was not achieved with antigen-coated tolerant lymphocytes. Another model utilized the ability of B cells to bind antibody-antigen complexes. Spleen cells from TxBM mice, incubated in vitro with anti-fowl gammaG-fowl gammaG.NIP, were injected with or without normal TDL (a source of T cells) into irradiated hosts. Only mice given both cell types could produce an anti-NIP antibody response. In a further experiment, spleen cells from HGG.NIP-primed mice were injected together with NIP-coated B cells (prepared as above) into irradiated hosts. A substantial anti-NIP antibody response occurred. If, however, the T cells in the spleens of HGG.NIP-primed mice were eliminated by treatment with anti-theta serum and complement, the NIP response was abolished. It was concluded that antigen-coated B cells could not substitute for T cells either in the primary or secondary response. Treatment of T cells from unprimed or primed mice with mitomycin C impaired their capacity to collaborate with B cells on transfer into irradiated hosts. Taken together these findings suggest that before collaboration can take place T cells must be activated by antigen to differentiate and in so doing may produce some factor essential for triggering of B cells.

Animals↗
PubMed1971

Surface immunoglobulins on thymus and thymus-derived lymphoid cells.

Lymphoid cells from thymus, thoracic duct lymph (TDL), and thoracic duct lymph in irradiated animals reconstituted with allogeneic thymus cells (TTDL) were labeled with radioiodinated anti-immunoglobulins using radioautographic techniques. Thymus and TTDL were labeled (14.4 and 37.0%, respectively) with anti-light chain protein after prolonged exposures (30-60 days). No labeling was observed on thymus and TTDL with anti-polyheavy chain globulin. In contrast 18.5-19.0% of TDL labeled on short exposure (6 days) with anti-polyheavy chain and anti-light chain materials. It is proposed that the difference between the labeling observed on short exposures versus long exposures can be related to the difference in surface density of immunoglobulins between nonthymus-derived (B) and thymus-derived (T) cells. The distribution of labeled cells in the thymus was preferentially among the larger cells (greater than 10 micro diameter). The TTDL population was mostly composed of a larger, blast-like population and the distribution of label was independent of size. As the thymus and TTDL preparations contain almost exclusively T cells, this represents a direct demonstration of surface immunoglobulin light chains on T lymphoid cells.

Animals↗
PubMed1971

Cell-to-cell interaction in the immune response. VI. Contribution of thymus-derived cells and antibody-forming cell precursors to immunological memory.

Collaboration between thymus-derived lymphocytes and nonthymus-derived antibody-forming cell precursors occurs in the primary antibody response of mice to heterologous erythrocytes and serum proteins. The purpose of the experiments reported here was to determine whether collaboration took place in an adoptive secondary antibody response. A chimeric population of lymphocytes was produced by reconstituting neonatally thymectomized CBA mice soon after birth with (CBA x C57BL)F(1) thymus lymphocytes. These mice could be effectively primed to fowl immunoglobulin G (FgammaG) and their thoracic duct lymphocytes adoptively transferred memory responses to irradiated mice. The activity of these cells was impaired markedly by preincubation with CBA anti-C57BL serum and to a lesser extent by anti-theta-serum. Reversal of this deficiency was obtained by adding T cells in the form of thoracic duct cells from normal CBA mice. Cells from FgammaG-primed mice were at least 10 times as effective as cells from normal mice or from CBA mice primed to horse erythrocytes. These results were considered to support the concept that memory resides in the T cell population and that collaboration between T and B cells is necessary for an optimal secondary antibody response. Poor antibody responses were obtained in irradiated mice given mixtures of thoracic duct cells from primed mice and of B cells from unprimed mice (in the form of spleen or thoracic duct cells from thymectomized donors). In contrast to the situation with T cells, the deficiency in the B cell population could not be reversed by adding B cells from unprimed mice. It was considered that memory resides in B cells as well as in T cells and that priming probably entails a change in the B cell population which is fundamentally different from that produced in the T cell population.

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