bluuebunny/crossref_metadata_2025 huggingface dataset:
Rat T lymphocyte antigens comparable with mouse Lyt-1 and Lyt-2,3 antigenic systems: characterization by monoclonal antibodies.
Authors: Matsuura A , Ishii Y , Yuasa H , Narita H , Kon S , Takami T , Kikuchi K
Published: December 2022

Rat T lymphocyte antigens were defined by using two distinct monoclonal antibodies (R1-3B3 and R1-10B5). R1-3B3 antibody, when tested for its reactivity with rat lymphoid cells by immunofluorescence, stained almost all of thymus and T cells but not the majority of B cells and bone marrow cells. The antigen defined by R1-3B3 existed more abundantly on medullary thymocytes and peripheral T cells than on cortical thymocytes. Immunochemical data showed that R1-3B3 antibody recognized a single glycoprotein with a m.w. of 67,000, showing marked electric charge heterogeneity with isoelectric points ranging from 5.4 to 7.3. R1-10B5 antibody, on the other hand, had more restricted reactivity with rat T cells and labeled approximately 85% of thymus cells and 30% of the peripheral T cells but neither B cells nor bone marrow cells. These T cells positive for R1-10B5 appeared to be negative for W3/25 antigen, which has been shown to be the marker for the rat T cell subset associated with helper function. R1-10B5 antibody detected a basic glycoprotein complex consisting of sulfhydryl-linked subunits with 30,000 and 34,000 m.w. Although the antigen defined by R1-3B3 was resistant to trypsin digestion, the one detected by R1-10B5 was much more sensitive to trypsin cleavage. All of these data obtained with either R1-3B3 or R1-10B5 are quite comparable to those reported for mouse Lyt-1 or Lyt-2,3 antigens, and thus suggest that the antigens defined by R1-3B3 and R1-10B5 antibodies represent rat homologues of Lyt-1 and Lyt-2,3 antigens in the murine system, respectively.
Presence of an antigenic determinant common to rat IgE-potentiating factor, IgE-suppressive factor, and Fc epsilon receptors on T and B lymphocytes.
Authors: Huff T F , Yodoi J , Uede T , Ishizaka K
Published: December 2022

Polyclonal antibodies against purified IgE-potentiating factor were prepared in guinea pigs, and mouse monoclonal antibodies were prepared against inactive IgE-binding factor from a T cell hybridoma. The polyclonal antibodies and two of the monoclonal antibodies bound the IgE-potentiating factor, the IgE suppressive factor, and the inactive IgE-binding factor. The results indicate that the three IgE-binding factor molecules share a common antigenic determinant. The polyclonal antibodies and the monoclonal antibody bound intracellular IgE-binding factors that did not have affinity for either lentil lectin or peanut agglutinin, which suggests that the antibodies were directed against the peptide portion of IgE-binding factors. Pretreatment of Fc epsilon R+ T hybridoma cells and Fc epsilon R+ B cells with either the monoclonal or the polyclonal anti-IgE-binding factor (anti-IgE-bF) antibody prevented rosette formation of the cells with IgE-coated erythrocytes, whereas the same treatment failed to affect rosette formation of Fc gamma R+ cells with IgG-coated erythrocytes. Specific binding of the guinea pig anti-IgE-bF antibodies to Fc epsilon R on both B and T cells was confirmed by immunofluorescence. The results indicate that Fc epsilon R on B and T cells share a common antigenic determinant with IgE-binding factors. The F(ab')2 fragments of the guinea pig anti-IgE-bF induced the expression of Fc epsilon R on Fc gamma R+ lymphocytes and the formation of IgE-binding factors. The capacities of not only IgE, but also anti-IgE-bF, to induce both Fc epsilon R expression and IgE-binding factor formation indicate that Fc epsilon R on lymphocytes, rather than IgE, transmit the signal for the formation of IgE-binding molecules.
Leukotrienes: positive signals for regulation of gamma-interferon production.
Authors: Johnson H M , Torres B A
Published: December 2022

Leukotrienes B4, C4, and D4 were capable of replacing the helper cell or interleukin 2 requirement for gamma-interferon (IFN gamma) production by Lyt-1-,2+ cells from C57BL/6 mouse spleen cells at leukotriene concentrations as low as 0.002 microM. An antioxidant inhibitor (butylated hydroxyanisole) of lipoxygenase metabolism of arachidonic acid suppressed IFN gamma production. The suppression was significantly reversed by leukotriene C4, which further suggests that leukotrienes and possibly other substances produced by the lipoxygenase pathway of arachidonic acid metabolism play an important role in the regulation of IFN gamma production. All of these events may be related to activation of guanylate cyclase activity, since cyclic GMP also significantly reversed the suppressor effects of butylated hydroxyanisole in IFN gamma production. The leukotriene help for IFN gamma production was independent of DNA synthesis or cellular proliferation. The data are consistent with the hypothesis that lipxoygenase products of arachidonic acid metabolism may play a role in the mediation of interleukin 2 help in IFN gamma production. Cells that are rich sources of leukotrienes, then, should play important roles in positive regulation of lymphokine production.
In vitro and in vivo studies on protective and inhibitory antibodies against Plasmodium falciparum in the Saimiri monkey.
Authors: Fandeur T , Dubois P , Gysin J , Dedet J P , da Silva L P
Published: December 2022

Immunoglobulins (Ig) were purified from serum or ascitic fluids of Saimiri monkeys infected with Plasmodium falciparum and with differing levels of functional immunity. Their protective activity was assessed in studies of passive transfer of immunity in vivo, and their neutralizing activity was measured in studies of parasite inhibition in vitro in cultures of human or Saimiri RBC. Although protective and inhibitory antibodies were detected in different Ig preparations, the levels of these activities were not directly correlated. Some Ig preparations, showing high protective activity, provide little or no inhibition of the parasite in vitro. Conversely, inhibitory activity was present in Ig preparations unable to confer protection in vivo. These results indicate that protective antibodies are active through a more complex immune mechanism than simple neutralization probably involving cellular immunity.
Role of IgE receptors in effector function of human eosinophils.
Authors: Capron M , Spiegelberg H L , Prin L , Bennich H , Butterworth A E , Pierce R J , Ouaissi M A , Capron A
Published: December 2022

After analysis of the technical parameters of the rosette assay with human IgE-coated erythrocytes, Fc epsilon receptors for IgE (Fc epsilon R) on human peripheral blood eosinophils were compared to Fc epsilon R on lymphocytes and monocytes. Antibodies directed against Fc epsilon R on lymphocytes and monocytes inhibited the IgE rosettes formed by eosinophils from hypereosinophilic patients, which suggests that Fc epsilon R on eosinophils were antigenically related to Fc epsilon R on lymphocytes and monocytes. Fc epsilon R on human eosinophils were shown to participate in the killing effect of Schistosoma mansoni schistosomula in vitro in the presence of purified eosinophils from highly hypereosinophilic patients (blood counts greater than 3000/mm3) and anti-schistosomula IgE antibodies present in S. mansoni-infected patient sera. Similar levels of inhibition of cytotoxicity were obtained after preincubation of eosinophils with aggregated human IgE or with anti-Fc epsilon R antibodies, whereas preincubation with aggregated IgG or with anti-C3b receptor antibodies did not decrease the killing effect for schistosomula targets. This IgE-dependent cytotoxic capacity seemed restricted to eosinophils with an abnormally low density ("hypodense" cells) present only in highly hypereosinophilic patients. These observations might be related to nonparasitic situations in which increased levels of IgE and tissue or blood eosinophils are observed.
Natural killer activity in the rat. III. Characterization of transplantable large granular lymphocyte (LGL) leukemias in the F344 rat.
Authors: Reynolds C W , Bere E W , Ward J M
Published: December 2022

Six transplantable large granular lymphocyte (LGL) tumor lines in F344 rats were examined for natural killer (NK) and antibody-dependent cell-mediated cytotoxicity. Tumor cells from all six lines were highly cytotoxic, even at low effector to target ratios, when tested against NK-susceptible targets, but were unreactive against an NK-resistant target (C58NT)D) and a macrophage-susceptible target (P815). Three lines showed significant levels of lysis against antibody-coated tumor cells. After in vivo transplantation, the levels of cytotoxicity steadily increased in three lines and decreased in one. The cytotoxic activity of one line (RNK-16) remained high through 12 transplant generations. Tumor cells injected i.p. spread via the lymphatics to regional lymph nodes, mediastinal nodes, blood, and eventually the bone marrow. Leukemia occurred concurrently with organ enlargement and increased levels of NK. Studies in (F344 X W/Fu)F1 rats clearly demonstrated that the cytotoxic cells from leukemic animals were the transplanted tumor cells themselves and not merely the activation of normal host LGL. These results demonstrate that naturally occurring, transplantable LGL leukemias are an easily obtainable and excellent source of materials for those studies requiring a large number of functionally active LGL.
Phenotypic modulation of chronic lymphocytic leukemia cells by phorbol ester: induction of IgM secretion and changes in the expression of B cell-associated surface antigens.
Authors: Gordon J , Mellstedt H , Aman P , Biberfeld P , Klein G
Published: December 2022

Freshly explanted neoplastic populations from 22 cases of phenotypically well-characterized chronic type B lymphocytic leukemia were studied for their capacity to respond to the phorbol ester TPA in vitro. In all but four cases the secretion of IgM was either induced or increased, often to a high level. In contrast, the export of free immunoglobulin (Ig) light chains, an almost consistent feature of the B lymphocytic leukemias, remained relatively constant after TPA treatment. Parallel changes in leukemic cell surface phenotype were probed with both "conventional" and monoclonal antibodies, revealing some modulation of markers in every case investigated. A diminution in the level of surface Ig (preferentially IgD) and the accumulation of cytoplasmic Ig observed after phorbol ester treatment were accompanied by a corresponding reduction or loss of the B1 antigen and usually of B2 when present. The most consistent change induced by TPA was the appearance of BB-1, a marker of activated B lymphocytes, which was rarely expressed on fresh leukemic cells. Another marker of activated lymphocytes, LB-1, was also often induced or increased in its expression after exposure of the cells to TPA. The magnitude of the TPA response appeared to relate to the stage of maturation arrest of the individual leukemic clones rather than to any clinical parameter explored. The significance of the findings to normal B cell differentiation and their potential clinical utility are discussed.
Age-associated decline in precursor frequency for different T cell-mediated reactions, with preservation of helper or cytotoxic effect per precursor cell.
Authors: Miller R A
Published: December 2022

We have begun to apply limiting dilution methods to address the cellular interactions that underlie age-associated changes in the immune response. By 18 mo of age, mice of the long-lived (BALB/c X C57BL/6)F1 strain are found to have a consistent, three to fivefold decline in precursor frequency for several different T cell-mediated responses: a) IL 2 response to T cell mitogens; b) antigen-nonspecific CTL production in mitogen-stimulated, IL 2-supplemented responses; and c) proliferation in response to concanavalin A. We also find a diminished precursor frequency for IL 2-secreting, KLH-specific helper T cells in the draining lymph nodes of KLH-immunized mice. Despite the decline in the fraction of responding precursor cells, the amount of "effect" (cytotoxicity, IL 2, or proliferation) generated per responsive cell is not altered by age. We speculate that the decline in all of these assays may reflect a common, underlying defect, one that reduces the proportion of T cells that can generate a sizeable clone of proliferating cells. This defect seems to act in several different T cell subsets, and in responses to several activating stimuli: alloantigens, soluble proteins, or mitogens.
Differential recovery of circulating T cell subsets after nodal irradiation for Hodgkin's disease.
Authors: Haas G S , Halperin E , Doseretz D , Linggood R , Russell P S , Colvin R , Barrett L , Cosimi A B
Published: December 2022

To better understand the immunologic effects of lymphoid irradiation (LI), blood levels of T cell subsets were sequentially monitored in 15 patients before, during, and after irradiation treatment for Hodgkin's disease. Blood levels of all lymphocytes, T cells, and T cell subsets (defined by OKT4 and OKT8) fell dramatically and in similar proportions during early therapy, reaching levels less than 20 to 25% of control by the completion of mantle irradiation, and continuing at very depressed levels through the completion of therapy. Blood levels of OKT8-reactive (OKT8+) cells returned to pretreatment levels (402 +/- 38/mm3 vs 360 +/- 32/mm3 pretreatment) between 6 to 8 mo after LI, whereas blood levels of OKT4-reactive (OKT4+) cells returned to only 42% of previous values (242 +/- 22/mm3 vs 584 +/- 34/mm3 pretreatment) over the same period. The pre-LI ratio of OKT4+ to OKT8+ cells was 1.85 +/- 0.24 and fell to 0.65 +/- 0.05 between 6 to 8 mo after LI. During the recovery period, discrepancies of 208 +/- 32 cells/mm3 (3 to 5 months post LI) and 198 +/- 32 cells/mm3 (6 to 8 mo post LI) developed between the blood levels of OKT3+ cells and the sum of OKT4+ and OKT8+ cells. This suggests the emergence of OKT4+/OKT3-, OKT8+/OKT3-, and/or OKT4+/OKT8+ cells. In five patients, the sum of OKT4+ and OKT8+ cells was compared with the number of cells simultaneously co-stained by OKT4 and OKT8. It appeared that a significant proportion of the cells were OKT4+/OKT3- and OKT8+/OKT3- lymphocytes. We concluded that LI is similarly cytotoxic to peripheral blood T cell subpopulations. The reversed ratio after LI is a result of a slower repopulation of the peripheral blood by OKT4+ cells relative to OKT8+ cells. T cells after LI show a high degree of antigenic immaturity. It is postulated that the bone marrow that lies outside the fields of treatment and contains predominantly immature OKT8+/OKT3- cells is a major source of T cells repopulating the peripheral blood after LI.
Reduced in vitro immune responses of purified human Leu-3 (helper/induced phenotype) cells after total lymphoid irradiation.
Authors: Field E H , Engleman E G , Terrell C P , Strober S
Published: December 2022

Patients treated with total lymphoid irradiation (TLI) for intractable rheumatoid arthritis showed marked decreases in the in vitro proliferative responses of peripheral blood mononuclear cells (PBM) to antigens and mitogens. To determine whether an intrinsic deficit in helper/inducer cell proliferation contributed to decreased responses, cells of the helper/inducer phenotype were purified from the PBM of treated patients by using monoclonal anti-Leu-3 antibody and a modified panning procedure. The purified Leu-3 cells obtained after TLI showed a marked reduction in [3H]thymidine incorporation in response to allogeneic lymphocytes, PHA, Con A, and several protein antigens, as compared with that of cells from the same patients obtained before TLI. In addition, the quantity of Leu-3 surface antigen on the panned cells was reduced after TLI. The results suggest that TLI induces prolonged qualitative as well as quantitative changes in circulating Leu-3 T cells. These changes may contribute to the clinical effects of TLI.
Molecular identifications of HLA-DR4, MT3, and TB21 antigens on HLA-DR4 homozygous B cell lines.
Authors: Maeda H , Hirata R
Published: December 2022

The HLA-DR locus in the human major histocompatibility complex determines a series of polymorphic cell surface antigens; these antigens are composed of two noncovalently associated glycoproteins of 34,000 daltons and 29,000 daltons and are predominantly expressed on B cells, monocytes, and activated T cells (1). To date, 10 HLA-DR specificities have been well characterized by using alloantisera obtained from multiparous women (2). In addition to these DR antigens, two other B cell alloantigen systems (MT and MB) were proposed on the basis of the serologic data (3,4); the MB1 or MT1 specificities are found in association with DR1, DR2, and DRw6, whereas MT2 is associated with DR3, DR5, DRw6, and DRw8; MT3 is associated with DR4, DR7, and DRw9, and MB3 or MT4 is associated with DR4, DR5, and DRw8, respectively (3, 4). We have also described that the TB21 antigen is expressed in association with DR4, DR5, and DRw9 (5). The HLA-DR, MB, MT, or TB antigens are collectively referred to as class II antigens. The number of human class II antigens has been of primary concern because of their similarity to murine Ia antigens and especially because of their close relationship to certain diseases. With the aid of immunochemical means and alloantisera, it has been demonstrated that at least two loci control human class II molecules (6-10). The data presented in this report show the existence of three class II molecules carrying well-known allospecificities, DR4, MT3, and TB21, on HLA-DR4 homozygous cell lines.
Mouse alloantibodies capable of blocking cytotoxic T cell function. V. The majority of I region-specific CTL are Lyt-2+ but are relatively resistant to anti-Lyt-2 blocking.
Authors: Shinohara N , Kojima M
Published: December 2022

In an attempt to solve the conflict concerning the correlation between the Lyt-2 phenotype of T cells subsets and the type of the MHC antigens involved in the recognition by T cells, class 2 (I region) antigen-specific CTL were studied for their Lyt phenotypes and the sensitivity to the blocking effects of anti-Lyt-2,3 antibodies. To avoid contamination by CTL to class 1 antigens such as Qa antigens, A.TH anti-A. TL attackers and A.TH anti-A attackers were tested on LPS blasts of the A strain and the A.TL stain, respectively. By using these combinations, it was shown that the majority of I region-specific killers were Thy-1+, Lyt-1+23+. Specific target cell lysis by these cells were, however, found to be far less sensitive to the blocking effects of various monoclonal antibodies to the Lyt-2,3 antigens than conventional class 1-specific CTL. This conclusion was drawn by directly comparing the sensitivity of the I region-specific and K region-specific killing by identical numbers of the same attacker cells (A.TH anti-A). No significant difference was seen between the primary and the hyperimmune CTL. Lyt-2-, Thy-1+ killer cells with I region specificity could be induced when Lyt-2-depleted A.TH responder cells were stimulated in vitro. Such Lyt-2- killer cells were not induced to the H-2K alloantigen.
Influence of 2'-deoxyguanosine upon the development of DTH effector T cells and suppressor T cells in vivo.
Authors: Bril H , van den Akker T W , Molendijk-Lok B D , Bianchi A T , Benner R
Published: December 2022

Subcutaneous (s.c.) immunization of mice with allogeneic spleen cells can induce delayed-type hypersensitivity (DTH) to both major and minor histocompatibility antigens. Intravenous immunization with allogeneic spleen cells, however, induces a poor state of DTH. Furthermore, i.v. immunization with allogeneic spleen cells, especially if they have been irradiated, induces suppressor T lymphocytes. These suppressor T cells are capable of suppressing the host-vs-graft (HvG) DTH reactivity that normally arises after s.c. immunization. Moreover, they can suppress the development of anti-host DTH effector T cells during graft-vs-host (GvH) reactions. These models for HvG and GvH DTH reactivity were used to study the influence of 2'-deoxyguanosine (dGuo) and guanosine (Guo) on the generation of DTH-reactive T cells and suppressor T cells in vivo. It was found that daily i.p. administration of 0.01 mg dGuo to mice immunized i.v. partially prevented the generation of suppressor T cell activity, whereas daily administration of 0.1 or 1 mg dGuo resulted in a complete abolition. Administration of dGuo has no effect on the anti-host DTH reactivity by spleen cells from nonsuppressed donors except for when a daily dose of 10 mg is administered. This dose proved to be toxic for precursors of DTH effector T cells. Daily i.p. injection of Guo had no effect on the generation of suppressor T cells nor on the generation of DTH effector T cells. The effect of dGuo was found to be due to a direct effect on suppressor T cells and not to the induction of contrasuppressor cells. These data suggest a differential sensitivity of DTH-reactive T cells and suppressor T cells for dGuo. Because suppressor T cells and DTH-reactive T cells require proliferation for expressing maximal functional activity in the systems used, both cell types probably have different enzyme activities involved in the purine metabolism and similar deoxycytidine kinase activities, but have different nucleotidase (5'NT) activities, those in suppressor T cells being the lowest. If so, suppressor T cells will accumulate deoxyguanosine triphosphate, which causes an inhibition of the ribonucleotide reductase activity and thus of the DNA synthesis by these cells.
Cross-linking of B lymphocyte Fc gamma receptors and membrane immunoglobulin inhibits anti-immunoglobulin-induced blastogenesis.
Authors: Phillips N E , Parker D C
Published: December 2022

The Fc portion of rabbit anti-mouse immunoglobulin (Ig) antibodies interferes with anti-Ig-induced B lymphocyte activation as measured by DNA synthesis on day 3 of culture or maturation to Ig-secreting cells in the presence of soluble helper factors on day 4 or 5. To investigate this Fc-dependent effect at an earlier stage in B cell activation, rabbit IgG anti-mouse mu-chain- or delta-chain-specific antibodies were compared with their F(ab')2 fragments for the ability to induce mouse B cells to undergo blast transformation, as defined by an increase in cell volume during the first 24 hr of culture. Both F(ab')2 anti-Ig reagents induce blast transformation, although F(ab')2 anti-mu antibodies induce a greater size change than F(ab')2 anti-delta antibodies. Whole anti-mu or anti-delta antibodies do not induce blast transformation; however, in the presence of a monoclonal anti-mouse Fc gamma receptor antibody that blocks IgG binding to Fc gamma receptors (Fc gamma R), whole anti-mu or anti-delta antibodies induce blast transformation as well as their F(ab')2 fragments. Because the anti-Fc gamma R antibody alone has no effect on blast transformation, it appears that the simultaneous binding of membrane IgM (or IgD) and Fc gamma R by whole anti-Ig antibodies prevents this early event in membrane Ig-induced B cell activation.
Monoclonal antibodies specific for Ia glycoproteins raised by immunization with activated T cells: possible role of T cellbound Ia antigens as targets of immunoregulatory T cells.
Authors: Janeway C A , Conrad P J , Lerner E A , Babich J , Wettstein P , Murphy D B
Published: December 2022

Two monoclonal antibodies, Y-3P and Y-8P, specific for conventional mouse Ia glycoprotein antigens are described. Both were raised by repeated immunization of primed mice with activated T cells over a period of 1 yr, and both detect a new and broad public Ia specificity. Both of the antibodies react with I-A subregion-controlled A alpha:A beta complexes of all mouse strains apart from the responder strain (H-2d), as well as the equivalent of A alpha:A beta complexes in rats carrying seven independent haplotypes. These antibodies have great utility as almost universal Ia reagents. On the basis of these results, we propose that Ia antigens presented to the immune system bound to activated T cells are immunogenic, and may induce the production of Ia antibodies of novel and broad specificity. In addition, we propose that such bound Ia glycoproteins could be a target for immunoregulatory T cells, and could account for the specificity of suppression of graft-vs-host reactions and Ia-restricted helper T cells observed by others in F1 animals injected with parental T cells.
Class I restricted interaction between suppressor and cytolytic cells in the response to minor histocompatibility antigens.
Authors: Rammensee H G , Juretic A , Nagy Z A , Klein J
Published: December 2022

Inoculation of 10(8) unirradiated, minor H antigen-incompatible spleen cells into recipients leads to a failure of the induction of cytolytic T lymphocytes (CTL) specific for these antigens. In contrast, a strong CTL response against minor H antigens is obtained when the inoculated cells are irradiated or treated with Thy-1-, Lyt-1- or Lyt-2-specific antibody and complement. Thus the failure of CTL induction is probably due to suppression mediated by radiosensitive, Lyt-1+2+ T cells in the immunizing inoculum. We demonstrate here that the inoculated cells must share class I MHC loci with the recipients for the suppression to occur. Thus, the interaction between the suppressor T (Ts) cells and their targets (presumably the CTL precursors) is restricted by class I molecules. A disparity at class II loci between the inoculated cells and the recipients overrides the class I-restricted suppression, possibly through a positive allogeneic effect. The simplest interpretation of the class I restriction of Ts cell-target cell interaction is that the CTL precursors recognize minor H antigens in the context of class I molecules on the surface of the Ts cells themselves.
The T4 surface antigen is involved in the induction of helper function.
Authors: Rogozinski L , Bass A , Glickman E , Talle M A , Goldstein G , Wang J , Chess L , Thomas Y
Published: December 2022

The OKT4 monoclonal antibody reacts with a 62K m.w. glycoprotein present on a subset of human T cells with the capacity to help or induce B cell differentiation. The present studies were undertaken to determine whether the T4 molecule itself plays any role in the helper function mediated by T4+ cells. Using a series of monoclonal antibodies (OKT4, OKT4A-E), which react with distinct noncompeting epitopes of the T4 molecule, we found that OKT4A and OKT4E, but not OKT4, antibodies inhibited the induction of B cell differentiation by T4+ cells. This inhibition was apparent when using nonirradiated or irradiated T4+ cells, and was noted over a wide range of concentrations. Importantly, inhibition occurred only if the antibody was present during the first 24 hr of cell culture, and the presence of antibody did not alter the kinetics of induction of B cell differentiation. Thus, these data suggest that the T4 molecule plays an early, critical role in cellular interactions required for helper cell function.
Epitope mapping of the human surface suppressor/cytotoxic T cell molecule Tp32.
Authors: Martin P J , Ledbetter J A , Clark E A , Beatty P G , Hansen J A
Published: December 2022

The complexity of the suppressor/cytotoxic subset marker of human T lymphocytes was demonstrated by biochemical analysis, cross-blocking experiments, phylogenetic comparisons, and functional studies. At the biochemical level, the antigen was shown to be a heteromultimer of at least three polypeptide chains covalently associated into four different higher m.w. species. Sixteen different murine monoclonal antibodies were used to map epitopes of this heteromultimeric complex. Cross-blocking experiments undertaken with six directly labeled reference antibodies identified at least seven spacially distinct epitopes. Flow microfluorometric analysis of peripheral blood lymphocytes showed two distinct subpopulations of bright and dull-stained cells that differed approximately 10-fold in antigen density. The distribution of epitopes on bright and dull cells was not uniform because in several combinations, blocking was observed on bright cells only. Studies with nonhuman primate T cells demonstrated a high degree of phylogenetic heterogeneity in the antigen. The combined cross-blocking and primate data divided the 17 antibodies into 15 groups. Each of the antibodies was capable of blocking lysis by alloreactive cytotoxic T lymphocytes, indicating that the mechanism of inhibition may not necessarily involve hindrance of an active site.
Elimination of intestinally absorbed antigen into the bile by IgA.
Authors: Brown T A , Russell M W , Mestecky J
Published: December 2022

Polymeric serum IgA has been shown to transport antigens in the form of IgA immune complexes from the circulation into the bile. To test the hypothesis that this mechanism could aid in the clearance of intestinally absorbed antigens, mice were gastrically intubated with trinitrophenylated human serum albumin (TNP-HSA). After 3 hr, two groups were injected i.v. with either MOPC 315 (IgA, anti-TNP) or control ascitic fluid. One hour later, blood and bile samples were taken. Small amounts of antigen (0.0008% of the intubated dose) were detected in the serum of control animals by solid phase radioimmunoassay. In animals receiving anti-TNP IgA, serum levels were decreased significantly and intact antigen appeared in the bile, whereas no antigen was detectable in the bile of control mice. These results suggest that IgA-mediated hepatobiliary transport can function as one of the mechanisms for the elimination of intestinally absorbed antigens.
The murine lymphocyte receptor for IgE. I. Isolation and characterization of the murine B cell Fc epsilon receptor and comparison with Fc epsilon receptors from rat and human.
Authors: Conrad D H , Peterson L H
Published: December 2022

The Fc receptor for IgE (Fc epsilon R) on murine B lymphocytes was studied by using BALB/c mice infected 12 to 18 days previously with Nippostrongylus brasiliensis. B cells were enriched in the Sephadex G-10-passed lymphocytes by treating with anti-Thy-1.2 and complement (C). After stripping any cytophilic Ig with low pH, the B cells were 125I surface labeled; subsequently the membranes were solubilized with nonionic detergent, and putative Fc epsilon R components were allowed to bind to IgE-coated adsorbents. Bound radiolabel was eluted with low pH, and when examined by SDS-PAGE, was found to consist primarily of a relatively broad band centered at 49,000 m.w. (49K). Fluid-phase IgE could prevent the binding of the 49K component to the IgE solid-phase adsorbents. Rebinding studies further indicated that the 49K component exhibited a specificity for IgE, thus confirming that the 49K component was the murine B lymphocyte Fc receptor for IgE (Fc epsilon R). Some rebinding to rabbit IgG was observed, and by using 2.4G2, the monoclonal anti-Fc gamma 2b receptor (Fc gamma 2bR) antibody to isolate the IgG2b receptor, a clear distinction between the FC gamma 2bR and the 49K IgE receptor was demonstrated by SDS-PAGE analysis. Rabbit IgG was thus found to interact with both the 49K Fc epsilon R and the 59K FC gamma 2bR. The murine B lymphocyte Fc epsilon R was compared with the human B cell Fc epsilon R from the RPMI 8866 cell line and with the high affinity Fc epsilon R on rat basophilic leukemia cells by one- and two-dimensional gel analyses. The lymphocyte Fc epsilon R from mouse and human was found to be quite similar with respect to m.w. (45 to 50K) and isoelectric point (pI 4.5 to 5.0), whereas the basophil Fc epsilon R differed in both aspects.
Killing of Leishmania tropica amastigotes by factors in normal human serum.
Authors: Hoover D L , Berger M , Nacy C A , Hockmeyer W T , Meltzer M S
Published: December 2022

Amastigotes of Leishmania tropica and L. donovani were incubated with fresh or heat-inactivated normal human serum. Viability was estimated by amastigote conversion to promastigote forms and by the ability of serum-treated amastigotes to infect human monocytes. L. tropica, a parasite that causes local skin infection, was killed by fresh but not by heat-inactivated serum. The serum cytotoxic effect on L. tropica was inhibited by EDTA but not by Mg-EGTA. C2-deficient serum killed normally; C6-deficient serum was ineffective. These data indicate that L. tropica is killed by the complement membrane attack complex, in a sequence of reactions initiated by components of the alternate pathway. In contrast, L. donovani, a parasite that causes systemic visceral leishmaniasis, was 10-fold less susceptible to the cytotoxic effects of normal serum. Thus, a profound difference exists in the susceptibility of amastigotes of two species of Leishmania to a defense mechanism present in human serum. Serum complement factors may play an important role in limiting L. tropica to the skin. The resistance of L. donovani to such factors may be the primary reason for its ability to escape from the site of inoculation and cause catastrophic, disseminated disease.
Cloned cytotoxic T lymphocytes recognize cells expressing discrete fragments of the SV40 tumor antigen.
Authors: O'Connell K A , Gooding L R
Published: December 2022

Thirteen cloned long-term lines of H-2k anti-SV40 cytotoxic T lymphocytes were established by limiting dilution and analyzed for functional specificity. All thirteen clones are H-2Kk-restricted and require expression of the SV40 early region in target cells for cytolysis. By using adeno-SV40 hybrid virus-infected or plasmid-transfected target cells expressing known fragments of T antigen, we found that lysis by ten of these clones requires expression in target cells of determinants within the carboxy-terminal 185 amino acids of T antigen, whereas lysis by the three remaining clones requires expression in target cells of amino-terminal determinants on a 33K fragment of T antigen. None of the clones require determinants in the "mid-region" (amino acids approximately 246 to approximately 523) of the molecule. No correlation was observed between recognition by these clones and expression in target cells of the 53K cellular protein that binds to T antigen.
Thymus cell migration: analysis of thymus emigrants with markers that distinguish medullary thymocytes from peripheral T cells.
Authors: Scollay R , Wilson A , Shortman K
Published: December 2022

Peripheral T cells and cells from the thymic medulla have many phenotypic characteristics in common, and both populations are quite distinct from cortical thymocytes. The cells that migrate out of the thymus (thymus migrants) may be detected in the periphery as fluorescent cells shortly after intrathymic injection of fluorescein isothiocyanate. Our previous work has established that they resemble T cells and medullary thymocytes rather than cortical thymocytes, and are fully functional. In this report, we consider several phenotypic characteristics that differ between medullary thymocytes and peripheral T cells, namely size, buoyant density, and sensitivity to a new monoclonal antibody (B2A2) and complement. By these criteria, the fluorescence-labeled thymus migrants in spleen and lymph node tend to resemble medullary thymocytes and are distinct from the majority of T cells that surround them. This suggests, but does not prove, that migrants originate in the medulla. After adult thymectomy, the small population of medullary-thymocyte-like cells disappears from spleen and lymph node, further supporting the idea that cells leave the thymus with a medulla-like phenotype, and acquire normal peripheral T cell phenotype only after their arrival in the periphery. Thus, although thymus migrants appear to leave the thymus in an immunocompetent state and are phenotypically mature by most criteria, there are a few final maturation steps that occur after arrival in the periphery.
Cellular mechanism of primary anti-Thy-1 antibody responses in vitro induced by uniquely immunogenic thymocyte antigens.
Authors: Isobe K I , Nakashima I , Nagase F , Kato N , Mizoguchi K , Kawashima K , Lake P
Published: December 2022

Thy-1 antigens are the only cell membrane antigens known to be able to induce primary antibody responses in vitro. We have shown that antigens from the thymocytes of mice and rats were highly immunogenic in cultures of murine spleen cells for the induction of Thy-1.1-specific plaque-forming cell responses, whereas antigens from other tissues, including brains and bone marrow, were poorly immunogenic, if at all. The thymocyte-specific Thy-1 immunogenicity was carried by disrupted cell membranes, and the specific activity for inducing responses was closely linked to Thy-1. We then tried to determine the mechanism of anti-Thy-1 antibody responses in vitro that were induced by the uniquely immunogenic thymocyte antigens. The thymocyte Thy-1 antigens behaved as T cell-independent class 2 (TI-2) antigens: they induced responses in athymic nude mice but not in CBA/N mice with a B cell defect. The apparent TI-2 responses to thymocyte Thy-1 did, however, require Thy-1+ cells in the responder, similar to anti-DNP-Ficoll responses. The full development of the anti-Thy-1 responses required the participation of splenic adherent cells (SAC). Nevertheless, the mechanism of the SAC dependency of anti-Thy-1 responses did not involve antigen presentation to lymphocytes by antigen-pulsed SAC, which contrasted with the finding that the presentation of antigen by live SAC to lymphocytes was indispensable for responses to DNP-Ficoll. The poor Thy-1 responsiveness of SAC-depleted spleen cells was fully restored by the addition of soluble factors (IL 1-like molecules) released from SAC into the culture, which did not replace the SAC-requirement of responses to DNP-Ficoll. It was concluded from these results that Thy-1 or Thy-1-linked structures on thymocyte membranes have an intrinsic activity to directly signal either TI-2 B cells or immature T cells, or both, for activation in the presence of soluble factors released from adherent accessory cells. This conclusion is discussed in relation to a hypothetical view that the thymocyte Thy-1 would physiologically mediate cell-to-cell interactions among special subsets of lymphocytes under thymic influence.
Immunoregulation by monoclonal sheep erythrocyte-specific IgG antibodies: suppression is correlated to level of antigen binding and not to isotype.
Authors: Heyman B , Wigzell H
Published: December 2022

Six different monoclonal IgG antibodies with specificities for sheep erythrocytes (SRBC) were tested for immunosuppressive ability. Four of them, one IgG3, two IgG2a, and one IgG1, could yield suppression of more than 90% of the anti-SRBC response. The remaining two antibodies, which were both IgG2a, were found to have no significant effect. The degree of suppression correlated well with the amount of antibodies used that could bind to SRBC, as measured by an ELISA assay. High avidity for SRBC was also a factor making the monoclonal antibody more efficient as an immunosuppressor. The response against antigenic determinants on the SRBC other than those for which the monoclonals were specific, was suppressed to an equal degree. This was established by immunizing mice with SRBC using monoclonal anti-SRBC antibodies that did or did not bind to goat RBC (GRBC). The PFC responses against both SRBC and GRBC were then measured. The anti-SRBC and GRBC responses were suppressed in parallel regardless of whether or not the monoclonal reacted with GRBC. None of the tested antibodies displayed any significant ability to enhance the anti-SRBC response. Thus, IgG1 is not the only murine isotype that can efficiently suppress the immune response against SRBC, but IgG2a and IgG3 can also exert this capacity. The mechanism of IgG-mediated suppression is not one of merely blocking single epitopes but involves the immunogenicity of the entire SRBC.
Mechanisms of the failure of resting B cells to present tetanus toxoid antigen to T cells.
Authors: Brozek C , Umetsu D , Schneeberger E , Geha R S
Published: December 2022

The present study examines the failure of resting B cells to present tetanus toxoid (TT) antigen to T cells. A hybrid antibody directed against TT and against human IgM was prepared from immunosorbent-purified rabbit anti-TT and rabbit anti-human IgM. Peripheral blood B cells were prepared by double rosetting with sheep red cells and were depleted of monocytes by double adherence over plastic plates and by passage over a Sephadex G-10 column followed by treatment with OKM1 and complement. B cells were preincubated with medium or with hybrid antibody (60 micrograms/ml) for 1 hr at 4 degrees C, washed, irradiated (2500 R), and tested for their capacity to present TT to an autologous TT-specific T cell clone. B cells coated with the hybrid antibody took up equivalent amounts of 125I-TT as monocytes or EBV-B cells and they internalized fluorescein-labeled TT. In contrast, in the absence of hybrid antibody B cells took up negligible amounts of TT antigen. However, B cells preincubated with the hybrid antibody failed to induce proliferation of autologous TT-specific T cell clones in response to TT. This was not corrected by the addition of partially purified human interleukin I. EBV-B cells sequentially pulsed with hybrid antibody and then with TT for 1 hr at 4 degrees C were equivalent in their capacity to induce T cell proliferation to EBV-B cells presenting soluble TT to the T cells. In contrast EBV-B cells pulsed with TT alone at 4 degrees C failed to take up and present TT. Thus the failure of hybrid antibody-coated resting B cells to present TT reflects an intrinsic inability of the resting B cells to present antigen. Monolayers of hybrid antibody-coated B cells pulsed with TT were prepared on anti-human Fab-coated dishes and were compared with monolayers of TT-pulsed monocytes for their capacity to adsorb TT-specific autologous T cells. In contrast to TT-pulsed monocytes, TT-pulsed hybrid antibody-coated B cells completely failed to bind TT-specific T cells. These results suggest that in addition to their poor antigen uptake resting B cells are incapable of processing antigen and generating the immunogenic moiety recognized by the T cells.
Human antigen-specific IgA responses in blood and secondary lymphoid tissue: an analysis of help and suppression.
Authors: McCaughan G W , Adams E , Basten A
Published: December 2022

Antigen-specific IgA responses to influenza virus were obtained from lymphocytes derived from human secondary lymphoid tissue but not from the circulating pool (blood). T helper cells for IgA were present in both the circulating pool and secondary lymphoid tissue, were of the Leu-3A+ subset, and were relatively radioresistant. In addition, T alpha cells were shown to be important, but not crucial, for IgA helper responses. T cell-dependent suppression of IgA responses was demonstrated with T cells from both mucosal and systemic lymphoid tissue and was mediated by a radiosensitive Leu-2a+ cell. In contrast to T cells, functional B cell precursors for antigen-specific IgA responses were found only in secondary lymphoid tissue and not in the circulating pool.
Identification of HBsAg determinants in immune complexes from hepatitis B virus-associated vasculitis.
Authors: Gupta R C , Kohler P F
Published: December 2022

Circulating immune complexes were characterized from 25 sera obtained from five patients with polyarteritis nodosa and three with cutaneous venulitis associated with hepatitis B virus infection. Complexes were isolated by polyethylene glycol and conglutinin-anticonglutinin precipitation methods and were analyzed for HBsAg and anti-HBsAg. Low pH was used to dissociate the complexes, and components were separated into antigen and antibody fractions by using immobilized protein A. In this study, three observations were significant: 1) complexes were frequent and quantitatively more in cutaneous venulitis than in polyarteritis; 2) the levels of HBsAg in the antigen fractions of polyarteritis were greater and correlated with the clinical improvement of the disease; the serum levels of HbsAg remained the same throughout the course of the disease; and 3) complexes from polyarteritis were not completely dissociable at pH 2.6 compared with those from patients with cutaneous venulitis and chronic active hepatitis. The antigen fractions electrophoresed in polyacrylamide gel with SDS demonstrated 6 to 10 protein bands with m.w. ranging between 17,000 and 120,000 daltons. To precisely define the polypeptide antigen moiety involved in the immune complex formation, a transfer blotting technique was used employing human anti-HBsAg globulin as probe. Polypeptides with m.w. 97,000, 49,000, and 23,000 were found to form complexes in both groups of patients.
Monocyte antibody-dependent cellular cytotoxicity in splenectomized subjects.
Authors: Gill P G , De Young N J , Kiroff G K , Leppard P I , McLennan G
Published: December 2022

Monocyte antibody-dependent cellular cytotoxicity (ADCC) was determined in normal subjects by using human A1 erythrocytes and immune human anti-A1 antiserum. The experimental data were fitted to a mathematical model and the values for maximal cytotoxicity and monocyte numbers required to produce 15% specific cytotoxicity (MD15) were subsequently computed and compared with the values for these two parameters estimated from the dose response curves. The values for both were significantly associated, and the mathematical model permitted precise quantitation of cytotoxicity in instances where this was impossible by standard methods. Maximal monocyte ADCC was significantly reduced in a group of splenectomized subjects, whereas the MD15 was increased. These findings emphasize the possible influences of the method of quantitation of ADCC and provide one explanation for the apparent conflict of published data.
Interferons as modulators of human monocyte-macrophage differentiation. I. Interferon-gamma increases HLA-DR expression and inhibits phagocytosis of zymosan.
Authors: Becker S
Published: December 2022

The development of HLA-DR (Ia) expression in the presence and absence of interferon-gamma was monitored in monocyte-macrophage cultures. Overnight incubation with doses as low as 5 U/ml gave elevated values for Ia expression and the maximum increase was obtained with 200 U/ml. In contrast interferon-alpha had only a slight effect on the expression of Ia at doses as high as 2000 U/ml. The increase seen at 24 hr was maintained during the first 2 days of culture. The interferon-gamma-treated cells expressed four to five times more Ia than fresh monocytes. During the same time, monocytes cultured in the absence of interferon expressed approximately two times the amount of fresh monocytes. When the surface density of Ia was calculated, the interferon-gamma-treated monocytes expressed twice that of the untreated cells. Major changes in morphology and size occurred between days 3 and 4 of monocyte to macrophage development. Consequently a rapid increase in Ia expression took place; however, when the surface density was calculated this value increased only slightly when the monocytes matured to macrophages. The interferon-gamma-treated cells continued to express more total Ia as well as having increased surface density of this antigen. Interferon-gamma was also added to monocyte-macrophages several days after culture initiation (days 3, 4, and 5). Despite being in different stages of maturation, the cells responded to the interferon with increased Ia expression and surface density. The phagocytic activity of opsonized zymosans was also monitored. In contrast to Ia expression, this activity was downregulated by interferon-gamma, and the lower levels of phagocytosis were maintained through the 7 days of observation. Thus, interferon-gamma appears to change the differentiation pathway of the monocyte. The signal stimulates an increased level of Ia that may assist in the initiation of immune responses, and at the same time downregulates the scavenger role of removing opsonized particles. Once the monocyte has received this specific signal it continues to develop in a pathway different from that of the nontreated monocytes.