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Biomedical subjects

I Green

Publications and source records attributed to I Green.

At least 217 records · Page 12Linked to original sources
PubMed1969

Transfer of responsiveness to hapten conjugates of poly-L-lysine and of a copolymer of L-glutamic acid and L-lysine to lethally irradiated nonresponder guinea pigs by bone marrow or lymph node and spleen cells from responder guinea pigs.

Hartley guinea pigs genetically unresponsive to hapten-PLL (poly-L-lysine) conjugates were lethally irradiated and given allogeneic bone marrow from Hartley responder animals. Many of the animals died of graft versus host disease before their response to 2,4-dinitrophenyl-PLL (DNP-PLL) could be measured. The immune response of the surviving recipient animals was evaluated by anti-DNP antibody production, development of delayed hypersensitivity to DNP-poly-L-lysine, as well as by lymph node cell stimulation in vitro by this antigen. 12 of 14 recipient animals thus treated made an immune response as measured by 2 of the 3 parameters. Strain 13 guinea pigs, genetically unable to respond immunologically to DNP-PLL and to DNP-GL (2,4-dinitrophenyl-L-glutamic acid L-lysine copolymer) were lethally irradiated and given bone marrow from (2 x 13) F(1) responder animals or strain 13 bone marrow and (2 x 13) F(1) lymph node and spleen cells. A high proportion of the animals survived this procedure; no evidence of graft versus host disease was observed. Three of three strain 13 animals irradiated and, given strain 13 bone marrow and (2 x 13) F(1) lymph node and spleen, and then immunized with DNP-PL, made a specific immune response. 7 of 10 irradiated strain 13 animals given strain 13 bone marrow and (2 x 13) F(1) lymph node and spleen made an immune response to DNP-GL. However, only one of six irradiated strain 13 animals made a vigorous immune response to DNP-GL after reconstitution with (2 x 13) F(1) bone marrow alone. The ability to transfer the immune response to PLL antigens from responder to nonresponder animals demonstrates unequivocally that the defect in the non-responder animals is immunological rather than due to some other type of non-immunological mechanism. The bone marrow contains all the immunological cells necessary for the expression of the PLL gene. However, the finding that (2 x 13) F(1) lymph node and spleen cells were more effective than (2 x 13)F(1) bone marrow cell populations (known to be a rich source of monocyte precursors) suggests that the cells in which the PLL gene function is expressed may be lymphocytes rather than monocytes and macrophages.

Animals↗
PubMed1969

A quantitative study of the stimulation of DNA synthesis in lymph node cell cultures by anti-lymphocyte serum, anti-gamma globulin serum, specific antigen, and phytohemagglutinin.

Rabbit anti-guinea pig lymphocyte serum is an efficient stimulus of the synthesis of DNA by guinea pig lymph node cells in vitro. The ability of ALS to stimulate lymphocytes is characterized by its lack of dependence on prior sensitization, the magnitude of the response it elicits, and the stimulation of all sensitive lymph node cells simultaneously within a very narrow range of ALS concentrations. In contrast to this homogeneous response to ALS, the stimulation of lymph node cells by antigen proceeds in graded fashion over a wide range of concentrations, thus reflecting the heterogeneity of the response of sensitized cells to antigen. PHA gives a response which is intermediate between that of ALS and antigen. ALS appears to have specificity for membrane determinants shared by lymphocytes but not found on other tissues. This specificity does not involve cell-bound gamma globulin. The serum activity mediating lymphocyte stimulation as well as cytotoxicity is readily removed by absorption with lymph node cells.

Animals↗
PubMed1969

Genetic control of immunological responsiveness in guinea pigs to 2,4-dinitrophenyl conjugates of poly-L-arginine, protamine, and poly-L-ornithine.

The ability of guinea pigs to respond immunologically to dinitrophenyl (DNP)-poly-L-arginine, DNP-protamine, DNP polyornithine, and to unsubstituted poly-L-arginine and protamine is linked to the presence of the poly-L-lysine gene. This gene has previously been demonstrated to control the immune response of guinea pigs to poly-L-lysine, to a copolymer of L-glutamic acid and L-lysine and to haptenic derivatives of these materials. Although the ability to respond to each of these highly charged compounds is linked to the presence of the poly-L-lysine gene, the cellular immune responses to these antigens is highly individually specific.

Animals↗
PubMed1969

Phospho-beta-glucosidases and beta-glucoside permeases in Streptococcus, Bacillus, and Staphylococcus.

The presence of phospho-beta-glucosidases and beta-glucoside permeases was found in strains of Streptococcus, Bacillus, and Staphylococcus. In streptococci, the phospho-beta-glucosidase activity depends on the antigenic group. The highest activity was found in strains of group D. In group D strains, phospho-beta-glucosidase activity is induced by beta-methyl glucoside and cellobiose but not by thiophenyl beta-glucoside (TPG). With the exception of four strains isolated in Japan, all strains of B. subtilis tested possess an inducible phospho-beta-glucosidase activity, beta-methyl glucoside, cellobiose, and TPG acting as inducers. S. aureus strains possess phospho-beta-glucosidase A but not phospho-beta-glucosidase B, whereas most S. albus strains show no detectable phospho-beta-glucosidase activity. The prompt fermentation of beta-methyl glucoside by S. aureus strains could serve as an additional criterion for their differentiation from S. albus. A comparative investigation of the active uptake of (14)C-TPG showed that a Streptococcus group D strain and a B. subtilis strain posses two inducible permeases with characteristics similar to the beta-glucoside permeases I and II of Enterobacteriaceae. In S. aureus, TPG is accumulated by a constitutive permease with high affinity for aromatic beta-glucosides and glucose. The active uptake of TPG by S. aureus appears to depend on the activity of the phosphoenol pyruvate-dependent phosphotransferase system.

Bacillus↗
PubMed1968

Distribution of antibody-forming cells of different specificities in the lymph nodes and spleens of guinea pigs.

The distribution of antibody-forming cells of different specificities in the lymph nodes and spleens of guinea pigs immunized with two separate antigens or with antigens bearing two determinants was studied. When animals were immunized with two soluble protein antigens or antigens in which the two antigenic determinants were on the same molecule, antibody-forming cells of different specificities were always randomly intermixed. However, when animals were immunized with two heat-aggregated particulate protein antigens and then boosted with soluble protein antigens, cells of different specificities were often seen to occur in groups. These results suggest that antibody-forming cells may not arise by the antigen-stimulated proliferation of precommitted antibody-forming cells, but rather antibody-forming cells arise by a transformation of uncommitted precursor cells as the result of their interactions with a locally produced material derived from the processing of antigen.

Animals↗
PubMed1968

Hapten carrier relationships in the DNP-PLL foreign albumin complex system: induction of tolerance and stimulation of cells in vitro.

Genetic nonresponder guinea pigs made tolerant to BSA and then immunized with DNP-PLL.BSA failed to make anti-DNP-PLL antibodies. Thus, tolerance to a carrier protein renders animals unresponsive to the hapten which it bears. The addition in vitro of DNP-PLL or DNP-GL to lymph node cell cultures derived from genetic responder animals immunized with these materials led to a significant stimulation of (3)H-thymidine incorporation into DNA. However, the addition of DNP-PLL or DNP-GL to lymph node cell cultures from nonresponder animals immunized with these materials failed to produce any stimulation of DNA synthesis. Furthermore, the addition of DNP-PLL to lymph node cell cultures from nonresponder animals immunized with DNP-PLL.BSA or DNP-PLL.OVA also failed to stimulate cell proliferation in spite of the fact that the lymph node cells of these animals were producing anti-DNP-PLL antibodies. The above facts suggest that the function of the PLL gene product is to act at an early crucial step in the immune mechanism to form an antigen-inducer complex. The specificity of this early step may be of a simple order and different than that of the antibody which is later produced in the immune response.

Animals↗
PubMed1967

A study of the passive transfer of delayed hypersensitivity to DNP-poly-L-lysine and DNP-GL in responder and nonresponder guinea pigs.

A study of the passive transfer of delayed hypersensitivity to DNP-poly-L-lysine and to DNP-GL was performed in Hartley guinea pigs. Delayed hypersensitivity to DNP-PLL and DNP-GL could be transferred successfully only by means of sensitized cells from genetic responder guinea pigs and in most cases, only into those guinea pigs genetically capable of responding to PLL. The inability to transfer delayed hypersensitivity to DNP-PLL or DNP-GL to genetic nonresponder guinea pigs is not the result of the early destruction of the transferred cells by an incompatible host, since it was shown that delayed hypersensitivity to ovalbumin could be successfully transferred from guinea pigs with the PLL gene into genetic nonresponder animals. The requirement of active participation of specific and genetically controlled host mechanisms in the successful passive transfer of delayed sensitivity to DNP-PLL and DNP-GL has been demonstrated.

Animals↗
PubMed1967

Specificity of the antibodies produced by single cells following immunization with antigens bearing two types of antigenic determinants.

A combination of double immunofluorescent technique and radioautographic localization of radioactive antigens was used to investigate the question whether single antibody-producing cells can make antibodies of more than one specificity after immunization with antigens bearing more than one determinant. When guinea pig gamma(2)-globulins, containing the F(ab')(2) and Fc determinants, were used to immunize rabbits, a small percentage of cells (3.7%) were stained with both the anti-F(ab')(2) and anti-Fc reagents. These results were shown to be due to the lack of absolute specificity of the detecting antigen and antibody reagents which can be obtained for use in this system. However, when immunological systems such as hapten-protein conjugates were used, and where completely specific antigen and antibody reagents could be prepared, the results were unequivocal. The individual lymph node cells from rabbits or guinea pigs immunized with hapten-protein conjugates produced antibodies against the hapten or antibodies against the antigenic determinants of the carrier molecule, never antibodies against both specificities.

Animals↗
PubMed1967

Cellular localization of anti-DNP-PLL and anticonveyor albumin antibodies in genetic nonresponder guinea pigs immunized with DNP-PLL albumin complexes.

Genetic nonresponder guinea pigs incapable of an immune response to DNP-PLL alone were immunized with DNP-PLL complexed to ovalbumin or bovine serum albumin. Under these circumstances the animals produce both anti-DNP-PLL antibodies and antibodies directed against the conveyor albumin. Thus immune response to DNP-PLL complexed to conveyor albumin molecules can serve as a simple model of hapten-carrier relationships. To explore these relationships the question whether these two types of antibody are synthesized by the same or by different plasma cells was investigated by a combination of a double immunofluorescent technique and radioautographic localization of radioactive antigen. It was shown that the anti-DNP-PLL antibodies and the antibodies against the carrier albumin molecule were produced in separate cells. No cell-producing antibodies with both specificities were detected out of 526 cells studied.

Animals↗